https://doi.org/10.1344/GeologicaActa2025.23.13 Casas J.M., Díez-Montes A., Pujol-Solà N., Beranoaguirre A., Proenza J.A., SÁnchez-García T., Álvaro J.J. & Murphy J.B. (2025).- From the Upper Ordovician unconformity to the core-mantle boundary: A review of the Ordovician events in the Canigò massif, Pyrenees.- We present a review of the stratigraphical, structural, geochemical, isotopic and geochronological data that document Ordovician events in the Canigò massif, eastern Pyrenees. Voluminous felsic magmatism, 15-20my in duration, occurred in the Mid to Late Ordovician, in two magmatic pulses that produced several laccolithic bodies, up to ca. 2000m in thickness, which became the protoliths of the various lithologies of the Canigò gneisses. There is also evidence of coeval basalt (now metabasites) with E-MORB affinities. Mid Ordovician uplift and erosion produced an Upper Ordovician (Sardic) unconformity. Synchronous extensional faults built propagation cleavage-free folds affecting a pre-Upper Ordovician succession and caused the erosion of up to 1500m of the underlying Cambrian-Lower Ordovician succession. Early Late Ordovician synsedimentary normal faults produced significant thickness variations in the Upper Ordovician successions. Compiled data match the Ordovician evolution described in Sardinia, Mouthoumet and Montagne Noire (Occitan Domain), but differs from the evolution of neighbouring areas, such as the Iberian, Armorican and Bohemian massifs, where thermal doming and magmatism developed earlier, in Furongian-Early Ordovician times, linked to the Toledanian unconformity. In the study area, uplift, erosion and extensional tectonics argue for a lithospheric uplift coeval with the development of felsic and basaltic (with E-MORB affinities) magmatism, and strongly suggests Mid to Late Ordovician plume activity beneath this segment of NW Gondwanan. The proposed plume would be one of a cluster of plumes impacting the Gondwana periphery that probably migrated inwards into Gondwana. Plume activity may be related to an early Palaeozoic superplume event, that contributed to the birth and development of the Rheic Ocean throughout the Gondwana margin breakup. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 09:59:24 GMT https://doi.org/10.1344/GeologicaActa2025.23.14 Corradini C., Corriga M.G., Pondrelli M., Spalletta C., Zocchi C. & Corradetti A. (2025).- Record of a sea level drop in the lower Mississippian limestones near Passo di Monte Croce Carnico (Carnic Alps, Italy).- The lower Carboniferous succession of the Carnic Alps represents the best-preserved example of such stratigraphic interval within the Alps, thus providing crucial insights for paleogeographic and paleoclimatic reconstructions. This research focuses on the combined biostratigraphic and sedimentological analyses of a stratigraphic section near Passo di Monte Croce Carnico (central Carnic Alps). The presence of two polygonal sedimentary structure-bearing levels suggests a sea level drop. Conodont biostratigraphy places these events within the lower part of the Gnathodus interregnum, correlating with the latest Tournaisian. These data, combined with insights from coeval sedimentary records within the Carnic Alps and from other basins worldwide, indicate that higher-frequency sea-level fluctuations, superimposed on an overall regressive trend, influenced the late Tournaisian evolution of the Carnic Basin. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.23.15 Mancini, A., Brandano, M., Gaglianone, G., Mannetta, D. & Ferràndez-Cañadell, C. (2025).- Coralgal buildup in a mixed carbonate-siliciclastic succession of the upper Eocene Sant Martí Xic Formation (Orís, Vic, SE Ebro Basin, Spain).- Coralgal buildups from the mixed carbonate siliciclastic succession of the upper Eocene Sant Martí Xic Formation (Orís, Vic, SE Ebro Basin, Spain) were studied. During the upper Eocene, the sedimentation in the Orís area was strongly influenced by global and local factors associated with the evolution of the Ebro Basin. The stratigraphic series in Orís shows first a transgressive sedimentary sequence characterized by floatstone to rudstone limestone with Discocyclina and Nummulites, which developed in a deeper and oligophotic environment and in a general context of humid climate conditions. The second sequence is formed by progradational deltaic deposits rich in Nummulites and developed under more arid climate conditions. Coralgal buildups occur interdigitated with these deltaic deposits forming two different lens-shaped bioherms that resulted in a coalescent buildup, with coral colonies sparse in a skeletal matrix of different grain-size. Corals grew in the mesophotic zone of the deltaic system affected by light fluctuations during periods of low siliciclastic input. The coralgal buildups of Sant Martí Xic Formation were thus influenced both by climatic changes and by the local detrital input from a deltaic system, associated with the uplift of the Catalan Coastal Range, highlighting the resilience of Eocene corals to environmental change. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.23.16 Oskay R.G. (2025).- Coal properties of Carboniferous Kurtköy coals (Zonguldak, NW Türkiye): Emphasis on rank, provenance of minerals and hydrocarbon generation potential- Late Carboniferous coal seams in the Zonguldak Basin (NW Türkiye) underwent several tectonic movements after the Late Permian; hence, these seams exhibit rank variations. This study presents initial insights into coal rank, mineralogical compositions, and hydrocarbon generation potential of Serpukhovian-Bashkirian coals within the Alacaagzi Formation from the south-easternmost part of the Basin. The examined seams are of bituminous C rank, and Tmax (442–445°C) and HI (221–288mg HC/g TOC) values indicate that they are at the set of oil generation. However, the low PI (0.01–0.02), BI (0.03–0.06), and QI (2.2–2.9) values and the possible presence of preserved cytoplasm spore-filling within the sporinite grains may indicate that the studied coals have only gas-generation potential. The results also show that the studied coals display relatively lower random vitrinite reflectance (%Rr 0.75–0.82%) and calculated Tpeak values (113–123ºC) using %Rr and micro-Raman spectra than their counterparts in the northern parts of the Basin (%Rr 1.18–1.52% and 173–206ºC). This difference seems to be related to the shallower burial depths of the studied coals or to the fact that they experienced relatively lower maximum attained temperatures than the northern parts of the Basin. Furthermore, the coal petrography and SEM-EDS data also suggest that the post-coalification tectonic deformation in the study area created space for circulating Ca- and Si-rich solutions within the coal seams and controlled epigenetic mineralization. Nevertheless, the redox conditions and clastic influx into the palaeomires also controlled syngenetic mineral formations, similar to the other parts of the Basin. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.23.17 Skelton P.W. & Gili E. (2025).- Myths and models of rudist ecology- Characterizing the ecology of rudist bivalves has long proved challenging, given their baroque shell shapes and the inconvenience of their extinction. Contrasting interpretations have taken hold in the literature via two different approaches. On the one hand, the appealing but simplistic hypothesis of ‘rudist reefs’ based on analogy with recent tropical coral reefs has been uncritically accepted by many, ignoring both the contrasts between the organisms concerned and the differing effects on sedimentation of icehouse versus greenhouse patterns of sea-level change. Worse, untested speculations have been spun on this suspect foundation, including the hypotheses of widespread photosymbiosis in rudists and of their competitive displacement of corals. On the other hand, opposed to such myth-making is an approach that respects the primacy of evidence. Here, synthetic interpretative models of rudist formations are built up from all circumstantial considerations and iteratively tested for compliance with field and laboratory observations. This process involves collating evidence ranging from well-supported inferences concerning rudist and coral palaeobiology, and growth fabrics and sedimentological contexts, to larger scale reconstructions of facies anatomy. The picture that commonly emerges –in contrast to the classic actualistic barrier-reef model– is of opportunistic settlements of usually low relief on flat-topped, tabular-bedded platforms distally grading into flanking clinoforms, without distinct intervening reefal edifices. Opportunities to test such synthetic models are provided by exceptional outcrops that display the full panorama of facies relationships. The latter is one of many achievements of detailed field studies over many years by the ‘Ramon Salas School’ in the Maestrat Basin. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.23.18 Ossò A., Artal P., Bakel B.W.M. van & Ferrer O. (2025).- Decapod fauna from the lower Aptian in the Valencian sector of the Maestrat Basin (NE Iberia)- The Forcall Formation in the Morella and Orpesa sub-basins of the Valencian sector of the Maestrat Basin has yielded a diverse assemblage of decapod crustaceans. A total of thirteen taxa are documented, representing the infraorders Achelata, Astacidea, Glypheidea, Axiidea, Anomura and Brachyura. Among these, one new genus, three new species, and one new taxonomic combination are proposed: Viapagurus covavidrensis n. sp., Eomunidopsis rigolleti n. sp., Morellosia maestratensis n. gen., n. sp., and Distefania pimientai n. comb. Comparisons with decapod faunas from other sub-basins of the Maestrat Basin reveal a notable degree of faunal homogeneity across the region. Furthermore, the palaeobiogeographic implications of these assemblages provide new insights into the distribution and diversity of Aptian decapod crustaceans. The findings highlight a significant faunal similarity with coeval basins such as the Garraf and Basque-Cantabrian basins and underscore the potential role of the Maestrat Basin as a biogeographic corridor linking decapod faunas of the Tethyan and Boreal realms. Overall, this study contributes to a more comprehensive understanding of the decapod assemblages of the Forcall Fm. and their relationships with contemporaneous faunas in the western Maestrat Basin and beyond. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.23.19 TomÁs S., Parcerisa, D. Cantarero I., Baqués V., Salas R. & Travé A. (2025).- Linking early diagenesis and relative sea-level changes in ancient corals: a multiproxy approach from the Benassal Formation (Lower Cretaceous, Maestrat Basin, E Spain)- The Aptian shallow-water carbonate platform of the Benassal Formation in eastern Spain (Maestrat Basin) contains facies dominated by scleractinian corals. Corals and coral reefs are widely used as environmental archives; however, the effects of their complex diagenetic evolution are a major factor impacting reliable reconstructions of the environments. This study addresses the environmental signatures (i.e. relative sea-level changes) and burial conditions that controlled the various diagenetic minerals present in the Aptian coral facies. A multiproxy approach including petrographic and geochemical evaluation reveals the diagenetic pathways, fluid compositions and timing accounting for the syn- to post-depositional history of this ancient coral facies. Cc1, which shows low Fe and Mn content and high Na content, precipitated within the primary porosity, alongside the replacement of coral skeletons, in a mixing zone dominated by marine waters. Cement Cc2, characterized by its higher Fe and Mn content and low Na values, precipitated in the mixing zone dominated by meteoric waters related to a relative sea-level drop. Cement Cc3, distinguished by low Fe and Mn content and high Na content, reflects a subsequent phase of increased marine influence, likely associated with a relative sea-level rise. Silica and isolated rhombohedral dolomite crystals formed concurrently in this mixing zone. During intermediate burial, saddle dolomite and cement Cc4 precipitated from high-temperature formation brines. Finally, during uplift, meteoric fluids caused the calcitization of previously formed dolomite rhombohedra. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.23.20 Sethy P.C., Naik A. & Nayak R. (2025).- Geochemical characterization and tectonic significance of the granite gneiss in the Tikiba Granitic Complex, Northwest Odisha, India- The study explores the Precambrian tectonic evolution and the growth of continental crust in the southern region of the North Odisha Singhbhum Craton (NOSC), delving into the potential petrogenetic processes and source characteristics. The Tikiba Granitic Complex (TGC) is in the contact area of the Eastern Ghat Mobile Belt (EGMB) and the NOSC. The present study involves the geochemical characteristics of TGC granitoids and their geochemical variations. Petrographically, the TGC is comprised of alkali feldspar granite, monzogranite to granodiorite. The major element geochemistry reveals calc-alkalic, ferroan to magnesian affinities, and a metaluminous, peraluminous and peralkaline character. It is enriched in LILE and HFSE like Yb, Sm, Zr and Y. The (La/Yb)N values range from 4.0–26.1 and exhibit distinct negative Eu anomalies (Eu/Eu*) (0.4-0.6). This granitic complex shows high ?REE contents of 176-860ppm with variable enrichment in LREE. Both REE and other incompatible element compositions define an A-type affinity. Based on geochemical data, we conclude that these granitoids have probably derived from a predominant crustal source with variable mantle characteristics in a post-orogenic setting. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.23.21 Albert-Villanueva E., Bover-Arnal T., Ferràndez-Cañadell C., GonzÁlez L., Esteban M. & Salas R. (2025).- Lower Miocene carbonate platforms of the Falcòn Basin (NW Venezuela) compared to the offshore Perla Field reservoir- Based on field data collected in the northern and southern Falcòn Basin (Venezuela), this paper presents a comprehensive monograph that reports on the age and sedimentary evolution of the San Luis and Churuguara formations. It integrates platform-to-basin depositional models through facies distribution and stratal architecture, a palaeogeographic reconstruction, larger foraminifera biostratigraphy, sequence stratigraphy, and the evaluation of the accommodation history. An additional aim is to compare these onshore mixed carbonate-siliciclastic systems with the Oligo-Miocene subsurface carbonate reservoir of Perla in offshore Gulf of Venezuela, considered the largest gas discovery ever in Latin America. The carbonate platforms studied formed as a result of a second-order transgressive event, and corresponded to distally steepened or undifferentiated ramps dominated by coralline algae and larger foraminifera. The presence of Miosorites americanus and Annulosorites spiralis dates the San Luis and Churuguara formations to the Early Miocene. The miogypsinid associations identified further distinguish between the Aquitanian and Burdigalian stages. The San Luis and Churuguara platforms exhibit a general aggradational trend, while the Perla carbonates have been interpreted as a retrogradational unit. Third-order T-R sequences interpreted from these successions were mainly influenced by differential tectonic subsidence. Additionally, major regional regressive events in the Falcòn Basin and Perla Field coincide with global glaciations, highlighting the influence of eustatic changes. However, the Perla reservoir exhibits significant differences in thickness, spatial extent and sedimentary architecture compared to the onshore equivalents. The differences arise from variations in tectonic and palaeotopographic settings, accommodation and sedimentation rates and influence of adjacent siliciclastic systems. As a result, predicting the sedimentary architecture of carbonate reservoirs in this region using a generalized depositional model has proven to be challenging. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.23.22 Canales-García I., Pérez-Cruz G., Orozco-AlmazÁn L. & Urrutia-Fucugauchi J. (2025).- Basement structural controls on the Jurassic sedimentary sequences in the Tampico-Misantla Basin, northeastern Mexico from a 3-D seismic reflection study- The Tampico-Misantla basin is a mature oil rich province in northeastern Mexico with large unconventional oil plays currently being explored. Results of a 3-D seismic reflection study of the basement and Jurassic sequences are used to analyze the basement influence on the sedimentary sequence and basin structure, by mapping the seismo-stratigraphic horizons for the (Tithonian) Pimienta, (Kimmeridigian) Taman/San Andrés, (Oxfordian) Santiago, (Callovian) Tepexic/Huehuetepec and (Bathonian) Cahuasas formations. The basement is characterized by stepped NW-SE tilted blocks of horst and grabens. The horst sections to the northeast are found at depths of 3,200m and get deeper up to 6,500m to the southwest. Blocks bounded by planar curved high angle normal faults with NW-SE and NE-SW orientation form a Triassic-Jurassic system, with two major pulses during the Bajocian and Oxfordian. Vertical slips of main faults are variable and may reach 2,000m. Basement blocks play major roles in defining the depositional processes, with thickness and distribution of overlying sedimentary units. Based on our analysis the Middle Jurassic Cahuasas Formation units were deposited predominantly in continental environments and exhibit large thickness variations. The Callovian Tepexic and Huehuetepec formations were deposited in transitional and shallow marine environments, with relatively uniform thickness and distribution. The Oxfordian to Tithonian Santiago, Taman/San Andres and Pimienta formations were deposited in marine environments, showing multiple fault deformation with tendency of progressively pinching out against the topographic highs. The thickness variation in the Santiago Formation suggests episodes of increasing subsidence and fault reactivation. The seismic volume models constraint the basement structures and Jurassic sequence stratigraphy in the Tampico-Misantla basin Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.23.23 Mutlu S. (2025).- Tectonic geomorphology of theSemdinli Yüksekova Fault Zone (SYFZ) and Baskale Fault Zone (BFZ) (SE Turkey): Evidence from morphometric analysis and neotectonic structures- The collision between the Arabian and Eurasian plates resulted in the uplift of The East Anatolian Province of Shortening (EAPS). Within the EAPS, the faulting mechanism is characterized by right- and left-lateral strike-slip faults, thrust faults, and a relatively limited occurrence of normal faults. When examined on a regional tectonic scale, about 70% of the deformation of the EAPS is controlled by strike-slip faults. However, the proportion of right- and left-lateral strike-slip faults contributing to this deformation remains unknown and is poorly understood. Two adjacent fault zones located at the southeastern margin of EAPS were selected to investigate the deformation associated with right- and left-lateral strike-slip mechanisms using morphometric analysis along with field observations. These fault zones are the Semdinli Yüksekova Fault Zone (SYFZ), which exhibits right lateral deformation and is defined as a seismic gap, and the Baskale Fault Zone (BFZ), which has a left lateral deformation and that caused a destructive earthquake in (23/02/2020, Mw: 5.9). To elucidate the relative degree of active tectonics of both fault zones, morphometric analysesis were applied alongside field surveys. An adaptation of the relative active tectonic Index (Iat) was computed for Baskale and Yüksekova-Semdinli sub-basins in the region. The results supported by field observations indicate that the drainage basins are largely controlled by fault activity and exhibit a youthful topographic character. Moreover, quantitative data derived from the Index of Active Tectonics (IAT) reveal that the SYFZ demonstrates very high tectonic activity, while the BFZ displays moderate levels of active tectonic deformation. These numerical findings, which indicate ongoing deformation, are further corroborated by field observations that clearly reflect the surface expressions of tectonic activity. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.23.24 Machek M., RoxerovÁ Z., Kusbach V., KucerÁkovÁ M. & Vratislav S. (2025).- Evolution of microstructure and texture in a small-scale high-temperature marble shear zone from the Ossa-Morena Zone (Iberian Variscan Belt)- This research investigates microstructures and crystallographic preferred orientation in a high-temperature Variscan small-scale shear zone within marbles from the south-western Ossa-Morena Zone (Iberian Variscan Belt). Quantitative microstructural analysis, and crystallographic preferred orientation data obtained via neutron diffraction and electron backscatter diffraction mapping allowed to infer the deformation mechanisms and active slip systems. The primary S2 foliation, formed during the Variscan D2 deformation phase, is characterized by high-temperature grain boundary migration recrystallization mechanism, coupled with intracrystalline slip on the c(0001)<-12-10> system. Ductile shear zone development, marked by a coarse-grained microstructure with pronounced shape preferred orientation parallel to the shear plane, involved both high-temperature grain boundary migration recrystallization and intracrystalline dislocation creep, accommodated by f{-1012} <10-11> and r{10-14} <-2021> slip systems. These results indicate a high-temperature extensional origin for the S2 foliation and the shear zone formation during the D2 deformation event of the Ossa-Morena Zone, linked to thermal effects from the Beja Igneous Complex plutonism and regional partial melting driven by asthenosphere upwelling (~353–335Ma). Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.23.25 Oliva-Urcia B., RomÁn-Berdiel T., Torres-Lòpez S. & Villalaín J.J. (2025).-Shortening-controlled magnetic fabrics in the Alpine thrust front of the Cantabrian Mountains- The magnetic fabrics (or anisotropy of magnetic susceptibility) are used in this work to decipher thrust kinematics in the Cantabrian Mountains (western Pyrenees). Most of the analyzed rocks (total of 51 sites) correspond to the Mesozoic rifting and post-rifting stages (Triassic, Jurassic and Cretaceous) rocks in the Asturian-Leonese region, whose alpine structure is controlled by south-verging, basement-involved thrusts. Paramagnetic minerals are scarce as shown by the thermomagnetic analyses, and maghemite/hematite predominates as carriers of the magnetic fabric. The rifting phase is recorded by a primary fabric that remained unaltered during the alpine contraction, whereas the magnetic fabric of the Albian and Upper Cretaceous rocks show a reorientation due to contraction, which is better recorded in the fine grained continental facies of the Utrillas Group than in the carbonatic rocks overlying them. In the contractional fabrics found, the magnetic lineation delineates the thrust front enhancing the changes of the local shortening direction along strike. This reinforces the hypothesis of a strong control of the thrust direction by inherited structures. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.23.26 Ruh J.B. (2025).-Grain-size reduction diminishes the impact of viscous shear heating in lithospheric mantle shear zones- Active plate tectonics require weak boundaries that accommodate large strain over long time periods. Many studies argue that shear heating converted from dissipated mechanical energy may be responsible for the necessary weakening in the mantle lithosphere to initiate and sustain weak plate boundaries. Here, I present simple numerical simulations of pure olivine systems with a composite diffusion-dislocation creep rheology coupled to a self-consistent grain-size evolution model to investigate the effect of grain-size reduction on shear heating. Results demonstrate that the weakening related to grain-size reduction and the activation of grain-size-sensitive diffusion creep undermines the importance of shear heating in mantle shear zones. Depending on shear zone width, shear velocity and apparent stresses, estimations on ideal shear zone widths and viscosities are presented. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.23.27 Bover-Arnal T., Pascual-Cebrian E., Moreno-Bedmar J.A. & Salas R. (2025).- Strontium-isotope stratigraphy of the Aptian–Albian transition in the western Maestrat Basin (E Iberia)- The Aptian–Albian transition in the Maestrat Basin (E Iberian Chain) encompasses two lithostratigraphic units: the Benassal and Escucha formations. In some sectors of the basin, such as the western Galve and Las Parras sub-basins, this stratigraphic interval recorded a progressive shift from widespread carbonate platform settings to coastal siliciclastic-influenced and coal-bearing environments. Due to the transitional nature of this interval, establishing a clear stratigraphic boundary between the upper part of the Benassal Formation and the lower part of the Escucha Formation is challenging. Additionally, there is no unanimous agreement on the age range of these formations. To shed light on the stratigraphic location of the boundary between the Aptian and the Albian, strontium-isotope analyses were carried out on thirteen low-Mg calcite oyster shells to derive numerical ages. In the Las Parras Sub-basin, the 87Sr/86Sr values obtained from the siliciclastic-influenced transitional deposits between the Benassal and Escucha formations, as well as from the lowermost part of the Escucha Formation, range from 0.707282±0.000002 to 0.707410±0.000002. These Sr-isotope ratios translate into numerical ages that constrain this stratigraphic interval to the early Albian. The oyster shells collected in the Galve Sub-basin exhibit a higher degree of diagenetic alteration. Nevertheless, the least altered specimens analysed from the lower part of the transitional facies between the Benassal and Escucha formations in this latter sub-basin yielded Sr-isotope ratios between 0.707197±0.000003 and 0.707256±0.000002. These values correspond to ages spanning from the latest Aptian to the earliest Albian. Accordingly, in most sectors of the western Maestrat Basin, the Aptian–Albian boundary is likely to be stratigraphically located at the lowermost part of the transitional facies between the Benassal and Escucha formations. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.23.28 Calugaru M.E., Munteanu M., Wäll M. & Isac A. (2025).- Trace element contents in bornite, chalcopyrite and pyrite (LA-ICP-MS) from Miocene porphyry copper-gold deposits from Metaliferi Mountains, Romania- In porphyry systems, valuable elements such as Au, Ag, Te, Se and Bi are found in trace contents associated with Cu and Fe sulfides. The relations between sulfide and the trace element contents, as well as the role of physicochemical factors in the uptake of different trace elements are still being assessed. This study focused on understanding how these elements are concentrated in selected sulfides (pyrite, chalcopyrite and bornite) and on the relation between the measured trace element composition of these sulfides and the hydrothermal alteration types in six porphyry deposits from Romania: Roșia Poieni, Bucium-Tarnița, Colnic, Rovina, Valea Morii and Bolcana. Based on LA-ICP-MS micro-analytical data, bornite is revealed as the main host for Bi (1077ppm), Se (810ppm), Ag (312ppm) and Te (43.73ppm). Chalcopyrite is also relatively rich in Se (199-403ppm), Ag (1.88-49.97ppm) and Te (1.95-36.06ppm). Pyrite is enriched in Co (98.81-704ppm), Ni (3.81-20.68ppm), As (2.13-166ppm), Se (24.65-729ppm) and Te (0.99-11.75ppm). These elements occur in the host sulfides as solid solution and as mineral microinclusions. Gold content is <0.2ppm in both Cu-Fe sulfides and pyrite. There is no significant variation in trace element ratio in chalcopyrite (Se/In) and in pyrite (Co/Ni, Co/Cu, Ag/Co) when comparing results from potassic-altered with chloritic-sericitic altered samples. Based on trace element results and micro-textural features of studied minerals, we suggest that these elements were initially incorporated in the crystal lattice during the potassic alteration and the overprinting of chloritic-sericitic alteration caused the exsolution and redistribution of trace elements within their host minerals. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.23.29 Travé A., Nadal J., Playà E., Salas R., Cantarero I., Baqués V., Cruset D., Gomez-Rivas E. & Martín-Martín J.D. (2025).- Fracture-related dolostones replacing Upper Jurassic–lowermost Cretaceous syn-rift deposits in the eastern Iberian Chain (eastern Spain)- Upper Jurassic and Lower Cretaceous limestones and dolostones serve as hydrocarbon reservoirs in the offshore area of NE Spain. Since similar dolomitized rocks crop out in the adjacent onshore Maestrat Basin in the SE Iberian Range, understanding the dolomitization and other diagenetic processes is key to assessing reservoir properties. The Maestrat Basin dolostones crop out as elongated, asymmetric bodies, ranging from tens of centimetres to kilometres in length and up to 150m thick, with a wedge-shaped geometry closely associated with fractures. These dolostones are calcium-rich with low concentrations of Mn, Sr, and Na, but variable Fe, indicating that the replacement of the host limestone was followed by dolomite cement precipitation. Fluid inclusion data suggest that dolomitization took place at temperatures ranging between 70 and 120ºC. Such temperatures, together with the high 87Sr/86Sr ratio and fluid salinity (16 to 23% wt. NaCl equivalent), reveal that the dolomitization process took place in burial conditions, from fluids that were infiltrated and likely interacted with Triassic, Liassic, and basement rocks. Although the exact age of dolomitization is not fully constrained, it is thought to coincide with fault-related dolomitization events of the same type previously described in the Maestrat Basin, likely during the latest Early Cretaceous and/or during the Late Cretaceous, in relation to the post-rift basin stage. Geochemical differences between the depocenters and structural highs may reflect the controls of the Maestrat Basin basin architecture on the composition and distribution of fluids. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.23.30 Gòmez-Ortiz, D., Martín-VelÁzquez, S., Martín-Crespo, T., Rodríguez-Santalla, I., de Ignacio-San José, C., Martínez-PagÁn, P., Martínez-Segura, M. (2025).- Electrical resistivity imaging to monitor water infiltration and contamination risk assessment in tailings ponds- This study investigates the internal structure and water content variations of the abandoned tailings ponds in the Hiendelaencina Ag-mining district, Spain, using Electrical Resistivity Imaging (ERI). The objectives were to delineate the geometry of the tailings deposits and to assess the spatial and temporal changes in water content within the ponds and the underlying geological units. The pollution risk assessment was evaluated as well. Six resistivity profiles were obtained during two separate field campaigns in September 2020 and May 2021, allowing for a comparison of resistivity data under different moisture conditions.The results revealed three distinct resistivity zones corresponding to the tailings, Cenozoic sedimentary deposits, and the underlying metamorphic basement, respectively. Temporal variations in resistivity indicates significant changes in water content between the two field campaigns, with increased water infiltration following spring rainfall. While no direct soil moisture measurements were available for calibration, the ERI results provide robust qualitative insights into relative water content changes and infiltration pathways.Notably, the fractured metamorphic basement showed higher water saturation, indicating vertical and lateral water flow from the tailings. These findings suggest that the tailings ponds are not impermeable, with water infiltrating into deeper layers, potentially transferring pollutants into the groundwater system. The study highlights the effectiveness of ERI as a non-invasive tool for investigating mining sites and provides important insights into the hydrological behavior of mine tailings, which is critical for environmental monitoring and risk assessment. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.24.1 Hernaiz-Huerta P.P., Ramos A. & Ardévol L. (2026).- The Muschelkalk (Middle Triassic) in the SE sector of Sierra del EspadÁn (Iberian Range, Spain)- Detailed mapping of the southeastern sector of the Sierra del EspadÁn (Eastern Iberian Range) shows that the Muschelkalk M2 intermediate unit is extensively distributed across the region, including its coastal areas. The M2 unit forms a thin (up to 25–30m), incompetent horizon predominantly composed of marly-dolomitic facies. Local stratigraphic omissions of this unit, resulting from facies changes or lateral wedging, occasionally led to continuous dolomitic successions corresponding to the Muschelkalk M1 plus the lower M3 (M3i) units. The M1 unit has been consistently mapped throughout the area, maintaining stratigraphic continuity with the underlying Röt facies, which cap the Buntsandstein B2 succession. Similar stratigraphic patterns have been observed in the adjacent Sierra Calderona to the South. These features collectively support the interpretation that both mountain ranges belong to the Mediterranean Triassic Domain, rather than to the Levantine-Balearic Domain. The Muschelkalk is transitionally overlain by a previously undescribed thick marly-clayey succession, which includes thin, well-bedded dolostones, resembling those of the lower M3 (M3i) unit, and abundant packages of dolomitic breccias. This newly identified interval is herein provisionally interpreted as a possible stratigraphic unit, the “supra-Pina de Montalgrao” facies referring to its position overlying the uppermost Muschelkalk M3 (M3s) Pina de Montalgrao Formation, pending paleontological evidence to confirm its age. The dolomitic breccias are interpreted as the result of fragmentation of thin, well-bedded dolostones, possibly triggered by gravitational instabilities associated with late-stage reactivation of Permian-Triassic rifting. Nonetheless, a dissolution process involving stratigraphically related evaporitic deposits remains a plausible alternative origin for some of these breccias. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.24.2 Corchete V. (2026).- Electrical conductivity inside Mars calculated beneath the InSight landing site- In a pioneer study, the electrical conductivity structure is determined beneath a fixed location on the Martian surface: the InSight landing site. The dataset used to attain this goal is the magnetic data recorded by InSight, from which are calculated the magnetic field variations in both high and low frequency, by spectral analysis. These variations are used to determine the surface ratios of vertical to horizontal magnetic field components, which are considered as the observed data that must be described/satisfied by some electrical conductivity models proposed. These models are the expression of the electrical conductivity structure of Mars, beneath the InSight landing site, and they should be recalculated when the data provided by future missions will be available (e.g. the Exobiology on Mars (ExoMars) Mission). Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.24.3 Carlorosi J., TonarovÁ P., Gutiérrez-Marco J.C. & Hints O. (2026).- Discovery of Ordovician scolecodonts from Peru, with a review of Palaeozoic jawed polychaete records from South America- The fossil record of jaw-bearing polychaetes from South America is scarce, and only a few occurrences of Ordovician scolecodonts have been reported so far. Here, we document a monospecific jawed polychaete assemblage from the Darriwilian Lenodus crassus conodont zone of the San José Formation in the eastern Cordillera of Peru. The single species, Protarabellites luztejadae sp. nov., represents the oldest record of the family Ramphoprionidae worldwide and may point to the biogeographic origin of this group in Gondwana. The reconstructed jaw apparatus of P. luztejadae bears primitive characters such as the slightly enclosed myocoele, distinguishing it from the younger members of the family and providing insights into the evolutionary relationships with other labidognath families. The described assemblage is the first record of Ordovician scolecodonts from Peru, as well as from the northern part of the Central Andean Basin, and one of very few cases from where apparatus-based classification has been applied. However, the Palaeozoic scolecodonts in South America appear to be more common than generally thought. A review of poorly known regional literature shows that scolecodonts have been mentioned in various sites from Ordovician, Silurian, Devonian,and Carboniferous–Permian strata of Argentina, Bolivia, Brazil, Colombia, Peru, and Uruguay. This highlights the potential for future scolecodont studies in South America.. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.24.4 Santamaría-Pérez E., Medina-Cascales I., Martin-Rojas I. & Alfaro P. (2026).- Active faulting in the Betic External Zones (SE, Spain): The Alcoy Fault Zone- Evidence of active faulting is presented from a fault in the eastern Betic External Zones (SE Spain). New fault data are provided for the Alcoy Fault Zone, a structure whose Quaternary activity is currently under debate. This study includes a detailed structural and geomorphic characterization, along with a preliminary palaeoseismological analysis. This fault is ca. 13 km long, and two main sectors are defined based on its surface geometry: a SW sector striking N060E formed by a border fault strand, and a NE sector striking N040E to N065E, formed by a border and an intrabasinal fault strands. The Alcoy Fault Zone displays oblique kinematics, with a predominant left-lateral and a subordinate dip-slip component. Quaternary fault activity is evidenced by a qualitative and quantitative geomorphic analysis, where three geomorphic indices were applied (Smf, Vf and Bs). The fault presents a marked mountain front with low sinuosity. Cross-fault streams, which are deflected in a left-lateral sense, exhibit knickpoints that coincide with the fault traces and display highly incised valleys. Moreover, the morphology of their watersheds is consistent with an ongoing tectonic uplift in the area. Additionally, the palaeoseismological analysis performed in deformed colluvial deposits suggests a Holocene surface rupture history involving two events during the last ca. 1160 years. The results of this work represent the first step for the seismogenic characterization of the Alcoy Fault Zone and the base for further seismic hazard assessment studies in the External Zones of the eastern Betic Cordillera. However, additional seismicity studies will be required to determine whether the fault is basement-involved or represents a decoupled structure controlled by the Triassic evaporitic layer between the Variscan basement and the pre-Neogene Betic rocks. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.24.5 Molins-Vigatà J., Blanch X., Martín-Banda R., García-Sellés D., Gòmez-Novell O., García-Mayordomo J., Insua-Arévalo J.M. & Ortuño M. (2026).- Digital surface models derived from historical aerial imagery in highly anthropized areas applied to active fault studies (eastern Betics, Spain)- Landform recognition and surface analysis are critical in geomorphological and morphotectonic studies. In particular, the detailed study of the surface expression of active faults is essential for their characterization as seismic sources in fault-based seismic hazard models. However, increasing anthropogenic action has profoundly altered the natural landscape, degrading or erasing tectonic landforms, and limiting the accurate characterization of active faults in many regions worldwide. A paradigmatic example is the southeastern Iberian Peninsula, where extensive agricultural development over last decades has completely transformed the natural landscape. To address this limitation, we produced three historical Digital Surface Models (DSMs) using historical aerial imagery across two active faults in the Betic Cordillera: the Palomares and Llano del Águila faults. Two DSMs were generated for the Palomares Fault (one from the American B-series Flight, 1956–1957, and one from the Interministerial Flight, 1973–1986), and one DSM was generated for the Llano del Águila Fault from the Interministerial Flight, all with a spatial resolution of 2 × 2 m. We introduce Surface Roughness as a new diagnostic metric to assess quality and to identify model artifacts, while DEM of Difference analyses were used to quantify elevation changes and assess the consistency of the reconstructed surfaces. Rather than focusing solely on absolute geolocation accuracy, our approach emphasizes evaluating the reliability of the historical surface reconstruction. This methodology highlights the potential of historical aerial imagery to enhance active fault characterization and near-fault morphotectonic analyses in landscapes heavily modified by anthropogenic activity. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.24.6 Mercedes-Martín R. & Walaszczyk I. (2026).- Inoceramid constraints on the timing of Sant Corneli anticline uplift (Tremp Basin, South-Central Pyrenees, NE Spain)- The Sant Corneli Anticline is an asymmetric, westward-plunging structure at the termination of the Boixols Thrust (Tremp Basin, Spanish Pyrenees), which was emplaced in the Late Cretaceous and generated an elongated, westward-deepening foredeep basin. A stratigraphic and paleontological study of inoceramid bivalves in the southern flank of the Sant Corneli Anticline has provided refined constraints on the timing and lateral distribution of the synorogenic carbonate-marly units (growth strata) predating the emplacement of the mixed depositional systems during anticline uplift.Two stratigraphic units were identified and dated via inoceramid biostratigraphy: the upper Podega Member (marly limestone with slumps), and the Montesquiu Member (limestone alternating with marls). The upper Podega Member unit can be traced laterally southwest of the Sant Corneli Anticline, decreasing in thickness from 230 m in the west to 170 m in the east. Meter- to decemeter-scale soft-sediment deformation structures and syn-sedimentary faults attest to the occurrence of gravitational collapses. This unit spans the upper Santonian through the basal upper Campanian (in the European bipartite stage subdivision). In turn, the Montesquiu Member laterally decreases in thickness from 226 m in the west to 150 m in the east, and exhibits frequent intraformational unconformities and meter- to decemeter-scale soft-sediment deformation, indicative of active tectonism. This unit, placed in the middle- upper Campanian based on inoceramid biostratigraphy, precedes the sedimentation of shallower mixed depositional environments which are marginally affected by soft-sediment deformation features. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.24.7 Concha-Dimas A., GonzÁlez-Martín A. & Bach-Plaza J. (2026).- Updated doline inventory and revision of geomorphological aspects that influence karst development at the Garraf Mountain Range, Catalonia, Spain- The Garraf Mountain Range (GMR), located in Catalonia, NE Spain, is a calcareous karstic region subjected to intense anthropogenic influence, primarily due to the presence of numerous urban areas and extractive activities. Utilizing a new 2x2 m LiDAR-derived Digital Elevation Model (DEM), we updated the doline inventory, increasing the count from 710 collapse dolines to 968.The main objective of this study was to provide a preliminary characterization of the spatial distribution of the updated doline dataset across the entire GMR relative to hydrological issues and geological hazards. Factors that influence karst development like lithology, regional lineaments, and drainage network, along with slope, and altimetry were reviewed. Altogether, these aspects facilitated the delimitation of four distinct geomorphological blocks for GMR: Calafell, Ordal-Vilanova i la Geltrú, Central, and Pallejà-Gavà.No direct proximity relationship with structural lineaments traces was observed over doline occurrence. Dolines were more frequently associated with proximity to river streams and areas of high drainage density which do show structural control in their trend. These two facts aid in the definition of preferential directional paths for water running/infiltration that are important for quantifications of karst capture in water balance evaluations for GMR watersheds. Also, high concentrations of dolines near urban zones, landfills, and quarries were observed in the northeastern and southeastern sectors of the GMR, particularly in the municipalities of Vallirana and eastern Sitges, respectively. The updated inventory can be used in improving accuracy in water balance and karst hazard evaluations. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.24.8 Moreno-Bedmar J.A., Bover-Arnal T., Forner i Valls E., Lehmann J., Frau C., Simpson M.I., García-Penas Á. & Salas R. (2026).- Ammonite biostratigraphy of uppermost Barremian – Aptian stratigraphic sequences in the Maestrat Basin (E Iberia)- In the current work, three relevant new ammonite finds from the Maestrat Basin are reported and analyzed from a biostratigraphical point of view. Additionally, another important ammonite, originally published in the late 1950th, is reviewed. The relevance of these four specimens lies in the fact that they come from stratigraphic intervals in the Maestrat Basin where ammonites are exceptionally rare. The purpose of this study was to analyze these ammonites from the latest Barremian-Aptian interval from a biostratigraphic perspective, with the goal of accurately determining the age of the stratigraphic intervals. The analysis of these ammonites has confirmed the age of previously defined transgressive-regressive sequences within the Maestrat Basin and led to the revision of some of these age assignments. To enhance the correlation potential of the Maestrat Basin within a broader context, its sedimentary and ammonite records have been compared with one European basin and one North African basin. This more precise ammonite-based age calibration significantly advances the chronostratigraphic understanding of sequence stratigraphy in the Maestrat Basin, establishing it as one of the best age-calibrated basins of the Tethys. Thus, the Maestrat Basin serves as a key reference point for correlating other Tethyan basins within this time interval. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.24.9 Salas R., Guimerà J., Bover-Arnal T. & Nebot M. (2026).- Structuration and sedimentary response to continental Mesozoic rifting in northeastern Iberia- Iberia and its oceanic margins provide evidence of a large rift system developed in three phases: i) late Permian–Middle Triassic, ii) Late Jurassic, and iii) Barremian–early Albian. These rifting events were coeval with the opening of the Alpine Tethys, the North-Atlantic, and the Bay of Biscay domains, respectively. The three Mesozoic rifting phases controlled the development of Iberian intraplate rift basins, including the Maestrat and Garraf basins, which are the focus of this study. Each of these rifting stages was followed by a period of decelerated or post-rift thermal subsidence. The first post-rift phase, spanning the Late Triassic to the early Late Jurassic, was interrupted by a short-lived interval of rapid syn-rift subsidence during the Hettangian, here referred to as the Hettangian event. Rifting cycles 2 and 3 are separated by the Neocomian event, which corresponds to an interval of decelerated subsidence. The earliest rifting phase is associated with an early inception of saline tectonics in the Maestrat Basin, and was accompanied by magmatism and took place in an arid climate setting, whereas the second and third rifting stages were essentially amagmatic and occurred under humid (sub)tropical conditions. The structural style during polyphase rifting is characterized by extensional systems involving the uppermost part of the crust, with basal faults located at a depth of 7 to 10 km. The Maestrat and Garraf basins developed during the Barremian–early Albian period were bounded by decakilometric normal faults with kilometric dip-slip, and were later inverted during the Paleogene contraction, giving rise to the fold-and-thrust systems of the Iberian and Catalan Coastal chains. Vertical movements, uplift and fault-induced subsidence, and the prevailing climate conditions were the two principal controls on the sedimentary record of the Iberian intraplate rift basins. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.24.11 Ferreira A.R., Yesares L., GonzÁlez-Jiménez J.M., Blanco-Quintero I.F., Ferrero M. & Tenorio S. (2026).- Nanoscale pathway for the formation of Ni–Co–Fe sulfarsenides in the stockwork of the Filòn Norte–Tharsis deposit (Iberian Pyrite Belt)- This paper presents a micro- to nanoscale investigation of Ni–Co–Fe sulfarsenides from the stockwork mineralization of the Filòn Norte–Tharsis deposit in the Iberian Pyrite Belt (IPB). Micron-scale single-spot analyses and X-Ray mapping by Electron Probe Micro-Analyzer Example of (EPMA) of zoned gersdorffite (NiAsS)–cobaltite (CoAsS)–glaucodot (CoFeAsS) crystals reveal varying amounts of Co (25.4–36.0 wt%), Ni (0.02–8.06 wt%), and Fe (0.75–7.91 wt%), with a negative correlation between Ni and Co, and between (Co+Ni) and Fe. Nanoscale analysis using High-Resolution Transmission Electron Microscopy (HRTEM) shows that such variations are related to: (i) solid solution within the gersdorffite–cobaltite series, defined by alternating layers (tens to hundreds of nanometers) of isometric P213 gersdorffite with orthorhombic Pca21 cobaltite; and (ii) nanodomains of orthorhombic Pca21 cobaltite within a matrix of orthorhombic Pn21m glaucodot. At the nanoscale, gersdorffite, cobaltite, and glaucodot exhibit coherent, semi-coherent and incoherent crystallographic orientation relationships (COR), with slight (0.7–1.3°) to significant (5–16°) lattice misfit. The micro- and nanoscale compositional and structural variations in gersdorffite–cobaltite intergrowths are interpreted as inhomogeneous solid solution at low temperature, whereas in cobaltite–glaucodot likely reflect replacement-induced spinodal decomposition. The shift between both styles of mineralogical sitting of Ni–Co–Fe sulfarsenides is related to fluctuations of the physicochemical conditions (i.e., temperature, chemistry, fS2, and aAs) in parental hydrothermal fluids and/or to deformation rates during mineral growth. Our findings highlight the existence of distinct nanoscale pathways for the genesis and evolution of the Ni–Co–Fe sulfarsenides, mechanisms not previously documented in Volcanogenic Massive Sulfide (VMS) deposits of the IPB and elsewhere. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.1344/GeologicaActa2025.24.12 Lario J., SÁnchez-Moral S., Martín-Pozas T., FernÁndez-Cortés A., Cuezva S., Martín-GonzÁlez E., Pérez-Mejías C., Cheng H. & Cañaveras J.C. (2026).- The Túnel de la AtlÁntida (Lanzarote, Canary Islands): recon-structing Late Pleistocene-Holocene sea-level and paleoenviron-mental changes inside the world's largest underwater lava tube- The Túnel de la AtlÁntida (Lanzarote, Canary Islands) is the world's largest submerged lava tube, formed by the La Corona eruption during the Last Glacial Maximum (LGM). This study reconstructs the Late Pleistocene–Holocene sea-level and paleoenvironmental changes preserved within the tunnel through an integrated sedimentological, petrographic, mineralogical (XRD, SEM–EDS), stable-isotope, and geochronological (U–Th, 14C) framework. U–Th ages obtained from banded calcite coatings (~15–14.4 ky) indicate speleothem growth under subaerial (vadose) conditions during the Bølling–Allerød, when sea level remained below the tube. A mature biocalcarenite at -62 m shows epiphreatic fabrics and marine cements consistent with a Younger Dryas stillstand near the tunnel terminus. In the middle sector of the tube, tidal-ripple laminations and desiccation cracks record episodic emergence linked to early-Holocene hydrographic variability. Carbonate d13C and d18O values are generally positive, and petrographic textures reveal strong kinetic effects (evaporation and degassing), intermittent marine incursions, and arid microclimates that promoted isotopic enrichment. Motukoreaite, produced by alteration of marine basaltic glass and predating dated carbonates, represents the first reported occurrence of this mineral in a lava-tube environment. Together, these geological proxies capture the transition from LGM subaerial formation through deglacial inundation to early–mid-Holocene oscillations, providing a high-resolution record of coupled volcanic, oceanographic, and climatic processes in the eastern Atlantic. Submerged lava tubes such as the Túnel de la AtlÁntida therefore provide valuable natural laboratories for assessing sea-level and paleoclimate evolution in oceanic island settings. Article geologica-acta@geo3bcn.csic.es Wed, 08 Jul 2026 10:05:38 GMT https://doi.org/10.2478/mipo-2025-0006 Stepien E., Manecki M. & Bajda T. (2025).- Mimetite precipitation on Pb-clinoptilolite: an effective approach for arsenate removal from water.- This short communication proposes a novel approach to arsenate remediation using in situ precipitation of mimetite [Pb5(AsO4)3Cl], a sparingly soluble mineral phase with an apatite structure. The Pb2+ source was provided by a lead-modified zeolite (clinoptilolite) loaded with approximately 70 g Pb/kg. It was reacted with arsenate (50 mg As/L) and chloride (20 mg Cl/L) at initial pH values of 2 and 7. Mimetite crystallized on and in the vicinity of zeolite due to the reaction of Pb(II) desorbed from zeolite with arsenate and chloride ions present in aqueous solution. Mimetite formed rapidly resulting in efficient arsenate sequestration. At pH 7, arsenate removal reached 99.88% after 24 hr, with minimal lead release (<0.02 mg/L). These results demonstrate that lead-modified clinoptilolite is a promising material for a coupled sorption–precipitation mechanism which provides an effective strategy for arsenic immobilization in contaminated aqueous systems. Article irena.brunarska@uj.edu.pl Wed, 23 Jul 2025 10:00:00 GMT https://doi.org/10.4154/gc.2025.10 Ioan I. Bucur, Emanoil Săsăran & George Pleş (2025).- Schlagintweitella inopinata, a new genus and species of Dasycladales (green algae) from the Upper Jurassic limestones of Romania.- Within the Upper Jurassic deposits of the Cioclovina-Băniţa area (Southern Carpathians), an outcrop was identified that most likely corresponds to a cavern fill. In several clasts of this fill, including black-pebbles, we found a dasycladalean alga whose morphological features differentiate it from all other Jurassic-Cretaceous dasycladalean algae with two orders of laterals. This alga is described in the present work as a new species of a new genus: Schlagintweitella inopinata nov. gen., nov. sp. Article geologia.croatica@hgi-cgs.hr Mon, 30 Jun 2025 17:43:46 GMT https://doi.org/10.26879/1518 Tom T.P. van der Linden, Michael P. Taylor, Amy Campbell, Brian D. Curtice, René Dederichs, Lucas N. Lerzo, John A. Whitlock, D. Cary Woodruff & Emanuel Tschopp (2025).- Introduction to Diplodocoidea.- Diplodocoidea is one of the most iconic clades of the giant sauropod dinosaurs, known for their elongated necks and tails, and distinctive skull morphology. This group, existing from the Middle Jurassic to the early Late Cretaceous, encompasses three main families: Rebbachisauridae, Dicraeosauridae, and Diplodocidae. These sauropods were globally distributed, demonstrating significant diversity in body plans, feeding strategies, and ecological niches. Diplodocoid paleontology has been marked by extensive studies focusing on skeletal morphology, biomechanics, histology, and evolutionary relationships. Significant research has also explored their ontogeny and niche partitioning, suggesting that diplodocoids had specialized adaptations for low- to mid-level browsing. This contribution is the introduction to a special volume that aims to synthesize current research on Diplodocoidea, offering insights into their evolutionary success, with subsequent contributions addressing their phylogenetic relationships, ontogeny, and morphological variation. Article pe_production@palaeo-electronica.org Sun, 29 Jun 2025 17:43:46 GMT https://vjs.pgi.gov.pl/article/view/34506 Hudson A.J.L., Hesselbo S.P., Hinnov L.A., Littler K., Page K.N., Riding J.B., Ruhl M. & Ullmann C.V. (2025).- Astrochronology of the Sinemurian Stage from the Llanbedr (Mochras Farm) core, NW Wales: Implications for the Early Jurassic timescale.- Early Jurassic palaeoenvironments were perturbed during episodes of major global climate and biogeochemical change at the Triassic–Jurassic boundary and Early Toarcian Oceanic Anoxic Event (T-OAE). Other poorly understood palaeoclimate fluctuations and carbon-cycle perturbations occurred between these episodes, including the mid-Sinemurian Liasidium Event and the Sinemurian–Pliensbachian Boundary Event. Understanding of the causes and significance of these phenomena is limited by uncertainties in the geological timescale, particularly for the Sinemurian Stage. In this paper we present new multiproxy geochemical data through the Sinemurian and earliest Pliensbachian stages from the Llanbedr (Mochras Farm) borehole (NW Wales). The Mochras record is apparently stratigraphically complete except in the Upper Sinemurian which is affected by a normal fault that removes the lower part of the Oxynotum Zone. A floating astrochronology is developed for the Sinemurian Stage based on identification of the 405-kyr orbital eccentricity “metronome” in weight percent calcium and stable organic carbon isotopes (d13Corg) from Mochras, together with data from the Robin Hood’s Bay base-Pliensbachian GSSP section in Yorkshire, UK. The results indicate a minimum duration for the Sinemurian Stage of 7.3 Myr (7.1 Myr from Mochras and an additional 0.2 Myr from Robin Hood’s Bay for the lower Oxynotum Zone). This interpretation of a long Sinemurian requires a short duration (~2 Myr) for the Hettangian stage. Article voljur@pgi.gov.pl Thu, 27 Jun 2025 17:00:00 GMT https://doi.org/10.18563/journal.m3.275 Tabuce R. & Gernelle K. (2025).- 3D models related to the publication: European mammal turnover driven by a global rapid warming event preceding the Paleocene-Eocene Thermal Maximum.- This contribution contains the 3D models described and figured in the following publication: Tabuce R., Marandat B., Adnet S., Gernelle K., Girard F., Marivaux L., Solé F., Schnyder J., Steurbaut E., Storme J.-Y., Vianey-Liaud M., Yans J. (2025). European mammal turnover driven by a global rapid warming event preceding the Paleocene-Eocene Thermal Maximum. Dataset renaud.lebrun@umontpellier.fr Thu, 27 Jun 2025 16:00:00 GMT https://doi.org/1344/GeologicaActa2025.23.12 Nurlu N. (2025).- New evidence on the timing of southern Neotethys closure from geochronology and geochemistry of Harmanli region ophiolite (southeastern Anatolia) and Late Cretaceous granitic rocks.- The felsic-intermediate intrusions of the Harmanli region are situated in proximity to the Tauride thrust front in southeastern Turkey. The region containing intrusive and ophiolitic rocks plays a crucial role in understanding the magmatic framework of Late Cretaceous felsic-intermediate igneous rocks in the Adiyaman region of southeastern Anatolia. The geological evolution of southeastern Anatolia during the Late Cretaceous is unravelled through integrated field observations, whole-rock geochemical, petrographic analyses, U-Pb zircon geochronology, and mineral chemistry of granitic rocks that intrude the Harmanli region ophiolite. The intrusions consist of tonalite, granodiorite, and in places granite, with a subvolcanic phase represented by granophyre, aplite, and granite porphyry. Mafic rocks including gabbro and diorite are also present with microdiorite and diabase in the subvolcanic phase. The new, high-precision LA-ICP-MS U-Pb zircon data provides crystallization ages for the mafic rocks of the Harmanli ophiolite (gabbro) ranging from 83.8 to 81.7Ma, while the felsic intrusives (granodiorite) have yielded crystallization ages ranging from 80.8 to 79.5Ma. Geochemical data indicate calc-alkaline, I-type magmatism characteristic of a subduction zone environment, consistent with the northward-dipping subduction of the southern Neotethys beneath the Tauride platform. The magmatic arc environment is characterised by the presence of ocean-ridge granite-normalised multi-element patterns, tectonomagmatic discrimination, and the biotite geochemistry of the intruded rocks. The mafic rocks of Harmanli region ophiolite exhibit distinct characteristics, including i) depletion in Nb, ii) enrichment in LILEs (Ce, Rb, K, and Th) and iii) a nearly horizontal pattern of HFSEs (high field strength elements) compared to N-MORB. The results suggest that the magmatism occurred during the Late Cretaceous (Campanian), with the intrusions forming at moderate to shallow crustal depths. Article geologica-acta@geo3bcn.csic.es Thu, 26 Jun 2025 14:00:00 GMT https://doi.org/10.35463/j.apr.2025.02.01 Felix Schlagintweit, Koorosh Rashidi & Reza Hanifzadeh.- Data on the unknown: The embryo of Iraqia simplex Henson, 1948 (larger benthic foraminifera; early Aptian, central iran).- Iraqia simplex Henson, the type-species of this orbitolinid genus, is classified among the Dictyoconinae Schubert that is principally defined by a simple megalospheric embryo. However, neither the original nor any later description of the taxon contained any specifications (or illustration) of this taxonomically important feature except that it should be situated eccentrically at the beginning of an early spiral stage. Abundant material from the early Aptian Taft Formation of Central Iran, that is in perfect conformity with Henson's Iraqi type-material, shows the presence of a simple embryo positioned centrically at the apex of the generally high-conical tests. Apart from other differences in the internal test structure, this feature therefore appears to represent a further distinguishing criterion to the allied genus Orbitolinopsis Henson. The available material also provides a relatively good overview of the so far unknown embryo's biometric variability. Among the Dictyoconinae, a centric embryo can be considered as the exception rather than the rule. Article george.ples@ubbcluj.ro Wed, 25 Jun 2025 17:00:00 GMT http://dx.doi.org/10.18563/pv.48.1.e3 Lemierre A. & Orliac M.J.- Lissamphibians from Dams (Quercy, SW France): Taxonomic identification and evolution across the Eocene-Oligocene transition.- The locality of Dams (Quercy, southwestern France) has yielded two fossil assemblages, one from the late Eocene and another from the early Oligocene, making it one of the few localities with infillings across the Eocene-Oligocene transition. At least 24 taxa (13 mammals, 11 snakes) have been identified in this locality. Study of the lissamphibian remains from Dams yields an Eocene and an Oligocene assemblage, with a total of eight taxa. The Eocene assemblage includes two unnamed salamandrine species, one unnamed pelobatid species and one pyxicephalid species (Thaumastosaurus). The Oligocene assemblage includes two unnamed pleurodeline species, one salamandrine species (Salamandra sansaniensis) and an unnamed pelobatid species. Among the eight taxa from Dams, one Eocene salamandrine and one Oligocene pleurodeline are identified for the first time in the Quercy. A review of the lissamphibians from the Quercy area identifies eleven taxa for the Late Eocene (MP19) and eight taxa for Early Oligocene (MP22), with a major turnover at the Eocene-Oligocene transition. This turnover occurs in a time of major climatic changes, with a significant decrease in temperature and precipitation and concurrent increase in seasonality in Europe, likely affecting specialized taxa. Article rodolphe.tabuce@umontpellier.fr Wed, 25 Jun 2025 16:00:00 GMT https://doi.org/10.2110/carnets.2025.2509 Stéphane Bersac & Didier Bert.- The Deshayesitidae (Ammonoidea, Ancyloceratina) in the lower Aptian (Lower Cretaceous) of the Les Ferres Aptian Basin (southeastern France).- In the present work, we study 335 specimens of Deshayesitidae (Ammonoidea) from the vicinity of the village of Les Ferres (SE France). The Deshayesitidae is the current key family for the ammonite biostratigraphy of the lower Aptian (Lower Cretaceous). Despite poorly preserved, the studied material could have been identified at species rank in most cases and allowed establishing the biostratigraphic frame of the lower Aptian of the study area. The results are as follows: (1) the studied samples range from the Deshayesites forbesi Zone to the Dufrenoyia furcata Zone; (2) their ontogenetic sequence is described; (3) their evolutionary patterns are consistent with those observed in other samples of Deshayesitidae; (4) no dimorphism is conspicuous; (5) the identified taxa are, from earliest to latest: Deshayesites sp. (Deshayesites forbesi Zone, rounded ventral area probably without smooth siphonal band), Deshayesites multicostatus Swinnerton, 1935 (index of subzone, intermediate smooth siphonal band then rounded ventral area), Deshayesites grandis Spath, 1930 (index of subzone, longer smooth siphonal band then subtabulate ventral area on phragmocone), Dufrenoyia furcata (J. de C. Sowerby, 1836) (index of subzone and zone, even longer smooth siphonal band then subtabulate ventral area, onset of rounded to claviform latero-ventral tubercles in inner whorls) and Dufrenoyia dufrenoyi (Orbigny, 1841) (index of subzone, even more longer smooth siphonal band, latero-ventral tubercles claviform only). Article carnetsgeol@rediris.es Sat, 07 Jun 2025 17:43:46 GMT https://doi.org/10.2110/001c.138729 Rivera T., Malone D.H., Biek R.F., Lesmann S.R., Stevens G., Hacker D., Braunagel M.J., Griffith W.A. & Rowley P.D. (2025).- The Growth and Collapse of a Volcanic Field: Detrital Zircon U/Pb Geochronology and Provenance of the Oligocene Bear Valley Formation, Southwest Utah, USA.-The Bear Valley Formation (Fm.) is a distinctive eolian sandstone interbedded with thick volcanic rocks of the Marysvale volcanic field of southwest Utah, the southern part of which failed during eruptive activity along three mega-scale gravity slides. The formation is as thick as 300 m and extends over an area of >2,500 km2 in the Black Mountains and Markagunt Plateau. The Bear Valley Fm. is composed of tuffaceous sandstone interbedded with tuff, conglomerate, and polymict volcanic mudflow breccias. The sandstone beds are lithic arenite and lithic wacke that occur as massive beds with large-scale cross bedding. The Bear Valley Fm. occurs in the upper plate of the Markagunt gravity slide and is in both the upper and lower plates of the Black Mountains gravity slide. We used laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to acquire U/Pb dates of detrital zircons (N = 3, n = 346) from the autochthonous Bear Valley Fm. at Kane Spring and Jako Wash in the Black Mountains and the allochthonous Bear Valley at Sandy Wash in the central Markagunt Plateau. All samples are dominated by Oligocene zircons with maximum likelihood ages for deposition ranging from 23.6 to 24.0 Ma. The western-most sample from Jako Wash also preserves a slightly older group of zircons, indicating derivation from either the underlying Wah Wah Springs Fm. or another unit erupted from the Indian Peak caldera complex to the west. Thus, the upper Bear Valley Fm. was deposited within ~400 kyr before the emplacement of the Markagunt gravity slide at 23 Ma, reflecting accelerated uplift of the northern Marysvale complex that ultimately resulted in collapse and slide emplacement. Article thesedimentaryrecord@gmail.com Thu, 06 Jun 2025 18:00:00 GMT https://doi.org/10.1344/GeologicaActa2025.23.11 Martín-Closas C., Albalat D., Colombo F., Vilà M., Vicente A., Ossó À., Vicedo V. & Bover-Arnal T. (2025).- A refugium for charophytes during the maximum post-Palaeozoic sea-level highstand in the Turonian of Tarragona (Catalonia, Spain).- During the Cenomanian-Turonian interval, Europe was largely submerged under a shallow tropical sea within the Cretaceous Tethyan Archipelago, limiting non-marine lacustrine habitats to a few coastal lakes on the islands. This study reports an island refugium for charophytes in the Upper Cretaceous of Tarragona located at the palaeo-shores of the former Ebro Massif. The Upper Cretaceous of Tarragona comprises three carbonate formations that record a Cenomanian-Turonian transgressive-regressive sequence. This sequence is represented by a shallow marine platform to pelagic facies at the base, overlain by lacustrine and palustrine facies at the top. These non-marine deposits are newly attributed to the Turonian, based on the stratigraphic context and the presence of the species Atopochara trivolvis var. multivolvis. In addition to this dominant species, the charophyte assemblage contains a clavatoroidean species, represented by the thallus Munieria grambastii forma sarda, and is associated with freshwater gastropods. A. trivolvisvar. multivolvis had a wide distribution in the Northern Hemisphere at a palaeolatitude of around 40°N, occurring in the United States, Spain, France, and Armenia. The European localities suggest that the island charophyte flora in the Cretaceous Tethyan Archipelago was an impoverished version of the pre-highstand Early Cretaceous flora, which was dominated by clavatoraceans. This contrasts with coeval floras from the mainland (Chinese and Argentinian basins), where Turonian charophyte communities were diverse and already dominated by modern characean genera. The island lakes acted as refugia for the last clavatoracean-dominated charophyte communities before their complete replacement by modern characean communities during the latest Cretaceous. Article geologica-acta@geo3bcn.csic.es Wed, 04 Jun 2025 14:00:00 GMT https://doi.org/10.2110/carnets.2025.2508 Olev Vinn, Magdy El Hedeny, Mansour I. Almansour, Saleh Alfarraj & Ursula Toom.- The first record of a possible 'priapulid' from the lower Cambrian (Series 2) of Estonia.- The Yunnanpriapulus? sp. can be divided into three distinct parts: an anterior introvert, a slightly constricted elongated neck, and a slightly bulbous elongated posterior trunk. The fossil is preserved as a three-dimensional cast in the fine-grained sandstone and is oriented parallel to the bedding plane. Rapid burial helped protect the organism from scavengers and decay and provided the opportunity for fossilization via pyritization. The preservation of the specimen on a bedding plane resulted from the post-mortem transportation of the dead animal, likely due to a storm event. The priapulid likely hunted other worms for food. The similarity of the Estonian specimen to the Chinese species suggests that there may have been some faunal exchange between the remote continents of Baltica and South China in the early Cambrian. Article carnetsgeol@rediris.es Mon, 02 Jun 2025 17:40:25 GMT https://doi.org/10.1344/GeologicaActa2025.23.10 Larena Z., Arenas C., Ortiz J.E., Sanjuan J., Pascual A., Larraz M., Murelaga X. & Baceta J.I. (2025).- Quaternary tufas of the Inglares River valley: An example of changing slope stepped fluvial system, Álava, N Spain.- This study examines the factors that controlled the formation of Quaternary calcareous tufa deposits along the valley of the Inglares River (Álava, north Spain), currently fed by a karst-carbonate aquifer. It is based on stratigraphic, chronological (Amino Acid Racemisation, AAR), sedimentological, and δ13C and δ18O analyses, complemented by palaeontology (molluscs, ostracods and charophytes). The examined deposits occur as isolated bodies in the uppermost and downmost stretches of the valley, reaching45 and 25m in thickness, respectively. AAR dating classified them into two groups: Middle-Late Pleistocene (MIS 5e) and Middle and Late Holocene (MIS 1). The former only occurred in the downstream stretch. Up to eleven carbonate facies and minor allochthonous coarse detrital facies have been characterised and arranged into four distinct facies associations. Their features and bedding geometries suggested two main depositional settings: a low- to moderate-slope stepped stretch with small barrage cascades, dammed areas, and abundant palustrine zones (downstream system) and a high-slope stretch with steep stepped cascades and pools (upstream system). These settings respond to bedrock lithology and structural changes throughout the valley, which appear to be the principal factors controlling the tufa depositional architecture. Based on δ13C, an increase in aridity was inferred from the Middle-Late Pleistocene to Holocene. The isotopic differences between the upstream and downstream Holocene tufa might reflect the spatial evolution of δ13Cand δ18O in stream water through the approximately 8km long surveyed transect. Erosion due to sudden changes in water discharge may have caused the stratigraphic gap between the two tufa groups. Article geologica-acta@geo3bcn.csic.es Wed, 28 May 2025 14:00:00 GMT https://doi.org/10.20341/gb.2025.003 Coen-Aubert M.- Description of some Middle Devonian rugose corals from the Ma'der (eastern Anti-Atlas, Morocco).- Twelve species and four forms of Middle Devonian rugose corals from Morocco are described and illustrated. The material comes from four localities of the Ma'der Basin whose age from the Late Eifelian to the base of the middle Givetian is based on conodonts. Three taxa are new: Marennophyllum kaufmanni n. sp., Stringophyllum pedderi n. sp. and Siphonophrentis subaequalis n. sp. Heliophyllum moghrabiense Le Maître, 1947 is the only taxon common to the four outcrops and it suggests an Eastern North American influence at the level of the genus. Siphonophrentis cantabrica Birenheide, 1978, first described from Spain, is also a North Gondwanan species whereas Stringophyllum acanthicum (Frech, 1885), Acanthophyllum heterophyllum (Milne-Edwards & Haime, 1851), A. vermiculare (Goldfuss, 1826) and Spinophyllum blacourti (Rohart, 1988) are interesting for correlations with Western Europe and sometimes with Eastern Europe. Enallophrentis corniformis (Gürich, 1896) was defined in Poland, also in the Old World Realm. Farther to the east, there is a link with China where Siphonophrentis cantabrica is present. Finally, it must be mentioned that Australophyllum Stumm, 1949 is observed for the first time in Morocco. Article A.Anceau@ulg.ac.be Tue, 27 May 2025 16:00:00 GMT https://doi.org/10.2110/carnets.2025.2507 David J. Jutson, Michael D. Bidgood & Ben Johnson.- Microfossil and nannofossil analysis of the Upper Cretaceous to Lower Paleogene interval from two wells in the locality of the U.K. North Sea 'Silverpit Crater'.- Micropaleontological and nannopaleontological analyses have been carried out on ditch cuttings samples from two wells (Arco British 43/24-3 and British Gas 43/25-1), which penetrated the 'Silverpit Crater' structure in the Southern North Sea Basin (UK Sector). A stratigraphic gap (within the limits of resolution imposed by sampling constraints) has been identified between chalky limestones of Maastrichtian age, which are overlain by sediments of latest Paleocene age or younger. Accepting an impact-origin for the structure, the gap represents an impact-event, which occurred almost certainly post Cretaceous and Early Paleocene times and thus probably within the Late Paleocene, close to the Paleocene-Eocene boundary, ruling out an association with the K/P extinction impact. In well 43/25-1 a short interval of mixed microfaunas and nannofloras was observed, which is suggested as being related to 'resurgence deposits' entering the crater immediately after the impact-event. Article carnetsgeol@rediris.es Tue, 27 May 2025 11:34:46 GMT https://doi.org/10.1344/GeologicaActa2025.23.9 Domínguez-Carretero D., Villanova-de-Benavent C., Torró L., Pujol-Solà N., Bover-Arnal T., Mestre À, Aiglsperger T., Ramírez A., Rodríguez J., Espaillat J. & Proenza J.A. (2025).- Mineralogy, geochemistry and origin of karst bauxite deposits from the Reserva Fiscal Ávila, SW Dominican Republic.- The energy transition, which aims to reduce carbon emissions and to slow down climate change, demands an ever-increasing supply of the so-called "critical metals". Rare-earth Elements and Yttrium (REY) are among the most critical metals, as they are indispensable in most technologies associated with the generation and storage of renewable energy. In recent years there has been a growing interest in the potential of karst bauxites as non-conventional sources of REY and other critical metals such as Sc and Ga. The Sierra de Bahoruco (SW Dominican Republic) contains the most REY-enriched karst bauxites globally. In view of the high potential for hosting important REY contents, the Dominican Republic government has declared the Reserva Fiscal Ávila (RFA), a state-owned area within the Sierra de Bahoruco for assessment and exploration of its REY resources. In this study, we present the first data on the mineralogy and composition of bauxitic rocks from the RFA. The bauxitic deposits comprise clayey bauxites and Fe-rich bauxites that are composed predominantly of Al-oxyhydroxides (gibbsite, boehmite and nordstrandite), kaolinite and Fe-oxyhydroxides. The bauxites are enriched in REY, with a median value of 1,310ppm and up to 2,542ppm, with a consistent enrichment in Light REE (LREE) and Y compared to Middle REE (MREE) and Heavy REE (HREE). The positive correlation between the contents of REY and Th, and negative correlation with K, makes gamma-ray spectrometry an appropriate tool for the exploration. In addition, bauxitic rocks from the RFA contain significant Sc (up to 105ppm) and Ga (up to 54ppm) contents, and their extraction could potentially represent a substantial economic surplus to the revenue generated solely from the aluminum production. Article geologica-acta@geo3bcn.csic.es Wed, 07 May 2025 14:00:00 GMT https://dx.doi.org/10.18268/BSGM2025v77n1a031024 Andrés Michael Vite Galindo, Ana María Soler Arechalde & Verónica Ortega Cabrera.- Aportaciones a la cronología de la plaza de la Pirámide de la Luna, Teotihuacán, México - Contributions to the chronology of the Moon Pyramid square, Teotihuacán, Mexico.- The chronology of the Pyramid of the Moon square in Teotihuacán was determined through relative dating of the ceramic remains present in the different strata sampled, during archaeological excavations carried out since the 1960s, so establishing dating through archaeomagnetism will allow having a database that complements those obtained in different urban sectors such as La Ciudadela, Xalla and Teopancazco, thus generating greater certainty in the chronology and understanding of the phenomena of urban growth and renewal of the ancient city. In this work, the results of the first archaeomagnetic dating carried out in the Plaza de la Luna are presented, based on the sampling of three floors of gravel and a tamped floor, corresponding to the different construction moments of this space, with the aim of establishing a sequence chronological base, with which to compare future dating, both for the square and for other public spaces in the city. Short note camprubi@geologia.unam.mx Mon, 21 Apr 2025 16:00:00 GMT https://doi.org/10.2478/mipo-2025-0005 Walczak K.A., Wlodek A., Cuthbert S., Carter I.S.M. & Ziemniak G.- Long story encrypted in a small grain – zircon from meta-andesite in the Lower Köli Nappes reveals a complex history of the Virisen Arc Terrane, Scandinavian Caledonides, Sweden.- This short report presents the investigation results on the zircon from meta-andesitic rock from the Ankarede Volcanite Formation of the Lower Köli Nappe Complex in Scandinavian Caledonides. Previous U-Pb dating revealed a wide span of dates ranging from ca. 520 to ca. 480 Ma, with a mean age of 491 ± 3 Ma for the zircon cores. Using cathodoluminescence and back-scattered electron imaging, along with chemical mapping, we identified distinct zones within the zircon grains; 1) cores of clear magmatic provenance, 2) mantles also of magmatic origin but with a slightly different chemical composition and 3) zircon rims that suffered metamictisation and fluid-induced alterations. These findings highlight a complex growth history and alteration of studied zircon that affect the interpretation of zircon dating results. This research underscores the importance of detailed zircon studies for understanding the intricate processes involved in the magmatic and metamorphic evolution of Virisen terrain in Scandinavian Caledonides. Article jaroslaw.majka@geo.uu.se Fri, 18 Apr 2025 16:00:00 GMT https://doi.org/10.2478/mipo-2025-0005 Walczak K.A., Wlodek A., Cuthbert S., Carter I.S.M.. & Ziemniak G. (2025).- Long story encrypted in a small grain – zircon from meta-andesite in the Lower Köli Nappes reveals a complex history of the Virisen Arc Terrane, Scandinavian Caledonides, Sweden.- Long story encrypted in a small grain – zircon from meta-andesite in the Lower Köli Nappes reveals a complex history of the Virisen Arc Terrane, Scandinavian Caledonides, Sweden. This short report presents the investigation results on the zircon from meta-andesitic rock from the Ankarede Volcanite Formation of the Lower Köli Nappe Complex in Scandinavian Caledonides. Previous U-Pb dating revealed a wide span of dates ranging from ca. 520 to ca. 480 Ma, with a mean age of 491 ± 3 Ma for the zircon cores. Using cathodoluminescence and back-scattered electron imaging, along with chemical mapping, we identified distinct zones within the zircon grains; 1) cores of clear magmatic provenance, 2) mantles also of magmatic origin but with a slightly different chemical composition and 3) zircon rims that suffered metamictisation and fluid-induced alterations. These findings highlight a complex growth history and alteration of studied zircon that affect the interpretation of zircon dating results. This research underscores the importance of detailed zircon studies for understanding the intricate processes involved in the magmatic and metamorphic evolution of Virisen terrain in Scandinavian Caledonides. Article irena.brunarska@uj.edu.pl Fri, 18 Apr 2025 10:00:00 GMT https://doi.org/10.1344/GeologicaActa2025.23.8 Roqué-Rosell J., Ibáñez-Insa J., Granado P., Martín-Martín J.D., Álvarez-Pousa S., Cerdà-Domènech M. & Jiménez-Franco A. (2025).- Major-element analysis of the La Alquimia Compañía Anónimarock collection: Establishing a geochemical repository for the systematic classification of Iberian karstic bauxite and kaolin deposits.- The La Alquimia Compañía Anónimarock collection comprises a diverse range of rock samples collected across the Iberian Peninsula to identify bauxites suitable for aluminum oxide production. In this study, the major-element compositions of the rock samples were analysed using non-destructive portable X-Ray Fluorescence (XRF). The data were processed through Principal Component Analysis (PCA), calibrated and used to calculate the Index of Laterisation/Index of Bauxitisation (IOL/IOB) and the Chemical Index of Alteration (CIA). The PCA results revealed SiO#8322;, Al#8322;O#8323; and Fe#8322;#8322;O#8323; as the key components explaining most of the rock samples compositional variance. The calibrated data provided the major-element compositions, confirming that the rock samples predominantly correspond to karstic bauxites and kaolin deposits. For the karstic bauxite samples, the calculated IOL/IOB values, combined with theSiO#8322;--Al₂O₃--Fe₂O₃ ternary diagram, facilitated their classification. The samples were categorised into bauxitic types associated with regions of moderate uplift and karst development and near-lateritic types indicative of advanced weathering processes typical of more stable continental terrains under warm and humid climates. Besides, the calculated CIA values and the Al#8322;O#8323;-CaO*+Na#8322;O-K#8322;O ternary diagram were applied to classify the kaolin deposits. This approach also identified compositional variations among the kaolin rock samples, reflecting differences in their formation. The rock collection serves as a repository for advancing the regional understanding of the formation, distribution and geochemical trends of Iberian karstic bauxite and kaolin deposits. Moreover, these deposits hold significance as potential sources of Al, Li and REE, emphasising the value of the La Alquímia Compañía Anónima collection as a geochemical repository, particularly considering the growing demand for these critical resources. Article geologica-acta@geo3bcn.csic.es Wed, 02 Apr 2025 14:00:00 GMT https://doi.org/10.2110/carnets.2025.2506 Olev Vinn, Andrej Ernst, Mark A. Wilson & Ursula Toom.- Symbiosis between bryozoans with erect cribrate colonies and rugose corals from the lower Katian (Upper Ordovician) of Estonia.- Specimens of the rugose coral Streptelasma? sp. are found intergrown with a host bryozoan Oanduellina bella in the lower Katian of Estonia. Rugosa also occur in the bryozoan Proavella proava. This is the earliest and only known record of endobiotic rugose symbionts in cryptostome bryozoans from the Late Ordovician of Baltica. The erect bryozoan colonies provided symbiotic Rugosa with both a higher and more advantageous tier for feeding in the water column and a hard substrate that these encrusting Rugosa required. The rugose corals may have protected the bryozoans with their stinging cells against predators. The lack of malformations in the bryozoan zooid architecture and their normal dimensions around the Rugosa show that the relationship between the Rugosa and bryozoans could have been mutualistic, which is similar to many other Rugosa-bryozoan associations in the Late Ordovician of Baltica, although the exact nature of this association remains uncertain. Article carnetsgeol@rediris.es Tue, 01 Apr 2025 17:28:46 GMT https://doi.org/10.1344/GeologicaActa2025.23.7 Martín-Closas C., Lozano-Fernández I., Pérez-Cano J. & Bover-Arnal T. (2025).- The non-marine Lower Cretaceous of El Montsec thrust sheet (South-Central Pyrenees).- The aim of this study is resolving uncertainties on the lithostratigraphy and chronostratigraphy of the non-marine Lower Cretaceous of El Montsec thrust sheet, which contains the most developed record of such facies in the central Pyrenees (Catalonia, Spain). The materials, traditionally known as "El Montsec Charophyte Limestones", overlie upper Berriasian marine limestones and belong in fact to two different stratigraphic units, separated by an angular unconformity, which is represented by an irregular karstic surface. The lower unit, newly defined as the Cova dels Lladres Intraclastic Limestone Formation, is composed by metric-scale fining-upward parasequences with black intraclast conglomerates at the base covered by charophyte limestones at the top. This first non-marine unit is attributed to the lower Barremian Eurasian charophyte biozone Atopochara trivolvis triquetra. The upper non-marine unit, (revisited El Montsec Charophyte Limestone), is made of metric-scale fining-upward parasequences of charophyte limestones. Ferruginous marls at the base of the upper unit have yielded charophytes of the Hemiclavator neimongolensis neimongolensis Eurasian charophyte biozone, corresponding to the early-late Barremian boundary. El Montsec Charophyte Limestone Formation transitions laterally to La Pedrera de Rúbies Lithographic Limestones Formation, which includes the two famous fossil Konservat Lagerstätten of La Pedrera de Meià and La Cabroa. In sum, the non-marine Lower Cretaceous succession of El Montsec thrust sheet shows at its base a stratigraphic gap ranging from the upper Berriasian to the early Barremian. Furthermore, the angular unconformity separating the Cova dels Lladres Formation and El Montsec Formation clearly reflects the strong tectonic activity associated with the Barremian Iberian rift, which has been linked with the opening of the Bay of Biscay. Article geologica-acta@geo3bcn.csic.es Tue, 25 Mar 2025 14:00:00 GMT https://doi.org/10.2478/mipo-2025-0004 Bal S., Nejbert K., Michalski K., Domanska-Siuda J., Manby G., Holda-Michalska A. & Sláma J. (2025).- Petrographic and mineralogical characteristics of diagenetic overprinting in Neoproterozoic diamictites from Murchisonfjorden, Nordaustlandet, Svalbard.- Petrographic and mineralogical characteristics of diagenetic overprinting in Neoproterozoic diamictites from Murchisonfjorden, Nordaustlandet, Svalbard. The diagenetic processes exhibited by the Neoproterozoic diamictites from Murchisonfjorden (Nordaustlandet, NE Svalbard) are presented. Diamictite samples from the Cryogene Polarisbreen Group - the Petrovbreen Member of the Elbobreen Formation and the Wilsonbreen Formation were analysed. The mineralogical associations composed of chlorite group minerals (chamosite), albite, calcite, Fe-dolomite, clay minerals (illite) and quartz, recognized by integrated optical microscopy, scanning electron microscopy (SEM) and Raman spectroscopy techniques are typical for an advanced stage of mesogenetic diagenesis. Low-grade burial mineral associations were not identified. Our investigations indicate that during diagenesis increased heat flux accompanied fluid migration and remineralization. Identified Fe-Ti – oxides, anatase in thin sections and magnetite identified by rock-magnetic experiments are the products of the secondary diagenetic mineralization. The ferromagnetic carriers representing primary depositional remanence magnetization (DRM) were not preserved. Article irena.brunarska@uj.edu.pl Fri, 21 Mar 2025 10:00:00 GMT https://doi.org/10.1344/GeologicaActa2025.23.6 Alçiçek H., Bouchal J.M. & Alçiçek M.C. (2025).- Sedimentology and isotope geochemistry of Early Pliocene shallow lacustrine dolomitic succession in the Baklan Basin, Southwestern Türkiye.- A multiproxy study of the Lower Pliocene (Zanclean) shallow lacustrine succession in the southwestern margin of the Baklan Basin (southwestern Anatolia, Türkiye) provides new insights into the paleoclimatic and paleohydrologic evolution of an extensional basin located at the top of the western Taurides mountain range in the southeastern Mediterranean region. Detailed petrographic, sedimentological, palynological and stable isotope analyses on Mg-rich carbonates were carried out on the dolomitic succession in the Sapaca locality in the basin, indicating a vegetated, quiet to slow-moving, low-gradient, perennial, alkaline shallow lake environment under warm and arid climate conditions. The stable isotopic analysis of the dolomitic carbonates exhibits a narrow range of values (-1.31<δ18O<+5.82‰ and -7.10<δ13C<-2.10‰) and the δ18O-δ13C correlation (r=0.70) indicates a hydrologically closed lake. Two types of dolomite are identified in the studied section. Type-1 crystals formed mainly as a result of primary precipitation of dolomite in the shallow lake, whereas type-2 crystals probably indicate microbially controlled dolomite precipitation. The palynological record from Sapaca reveals that the Early Pliocene paleoenvironment was dominated by steppe and open vegetation with some isolated shrubs. Similar paleoclimatic and paleovegetational conditions are observed in other Anatolian basins and in the southern Mediterranean region. Therefore, the results of this study demonstrate that the shallow lacustrine system of the Baklan Basin serves as a good analogue for understanding Early Pliocene warmth and aridity in this region. Article geologica-acta@geo3bcn.csic.es Tue, 11 Mar 2025 14:00:00 GMT https://doi.org/10.1344/GeologicaActa2025.23.5 Benaiges-Fernández R., Palau J., Urmeneta J., Cama J., Soler J.M. & Dold B. (2025).- Comparative study of iron and trace element mobilization during Fe-oxide bioreduction in mine tailings: a case study of Ensenada Chapaco (Chile) and Portman Bay (Spain).- Bioreduction of Fe-oxides in mine tailings deposited under marine conditions releases Fe and associated trace elements (e.g. Ti, Ni, Cd, Pb), leading to contamination of the marine environment. Sea-Tailings Disposal (STD) along the northern coast of Chile (Ensenada Chapaco) and along the eastern coast of Spain (Portman Bay) results in an adverse impact on the environment. This paper focuses on bioreduction under marine conditions. To this end, two column experiments were carried out with samples from Portman Bay and Ensenada Chapaco. Lactate (i.e.organic matter source) was supplied during the experiments. The results obtained are compared with those from batch experiments performed under similar conditions.In the column filled with Portman Bay tailings, the high content of magnetite (15wt%) in contact with water gives rise to a large magnetite surface area and abundant Fe(III), which results in a high release of Fe(II) and Trace Elements (TE). Since Fe(II) adsorbs onto the magnetite surface reducing the availability of Fe(III), the magnetite bioreduction and the consequent TE release decrease after 2000h. By contrast, the magnetite bioreduction lasts longer (3000h) in the column with Ensenada Chapaco tailings. This is because a lower magnetite content in the tailings (1wt%) provides a smaller reactive surface area yielding less Fe(III). Consequently, the concentrations of Fe(II) and TE in the output solutions are lower, which slows down the Fe(II) adsorption onto magnetite. This results in a longer magnetite bioreduction. Bioreduction is regulated by the availability of Fe(III) in both columns. It is inferred that the bioreduction rate diminishes as a function of time and increases as a function of soluble Fe(II) concentration. Moreover, the concentrations of TE released from the two bioreduced tailings exceed the elemental concentrations under marine conditions. Article geologica-acta@geo3bcn.csic.es Thu, 27 Feb 2025 14:00:00 GMT https://doi.org/10.2478/mipo-2025-0002 Walters J.B.. & Gies N.B. (2025).- Syn-volcanic melt-rock reactions recorded in peridotitic xenoliths from Scania, S Sweden.- MinPlotX: A powerful tool for formula recalculation, visualization, and comparison of large mineral compositional datasets. MinPlotX is an open-source software for mineral formula recalculation and compositional plotting providing an easy-to-use stand-alone graphical user interface (GUI) as well as an advanced programming interface (API). The aim of MinPlotX is to provide publication-ready tables of mineral formulae and plots of mineral composition. The new GUI-based approach allows for a wider variety of calculation and plotting options, including both commonly used pre-defined mineral specific diagrams and a large variety of multi-dimensional diagrams that can be created quickly and easily by the user. The most powerful feature is the addition of nearly any kind of numerical or categorized metadata, such as sample name, analysis location, trace element concentration, age, and others, that can be used to subdivide or contour data. The modular nature of the program makes it possible to add new mineral formula recalculation and plotting routines, as well as other data science tools, without changing the overall structure of the program. Therefore, MinPlotX provides advanced users the means to add new routines and interact with the program through the API, while simultaneously providing a simple and effective platform for users who have no programming experience or do not have access to MATLAB®. Article irena.brunarska@uj.edu.pl Fri, 21 Feb 2025 10:00:00 GMT https://doi.org/10.1344/GeologicaActa2025.23.3 Urrutia-Fucugauchi J., Pérez-Cruz L., Venegas-Ferrer R. & Sánchez-Solis P. (2025).- The Chicxulub crater drilling program - continuous coring, well logging and core analyses reviewed.- Continuous core recovery, core scanning and logging are used for borehole characterization and petrophysical analyses in the Chicxulub drilling projects. The crater formed by an asteroid impact on the Yucatan platform ~66Ma ago, marking the Cretaceous/Paleogene (K/Pg) boundary. The K/Pg boundary clay layer, characterized by the Ir and platinum group element anomaly, has been studied worldwide. The crater has a ~200km rim diameter and is covered by up to ~1km of carbonate sediments, with studies based on geophysical surveys, drilling and ejecta deposits. The Yaxcopoil-1 borehole, drilled in the southern crater terrace zone sampled the post-impact carbonates, impact breccias and target Cretaceous carbonates. The M0077A borehole drilled in the marine sector sampled the peak ring succession, with the post-impact carbonates, impact breccias, melt and basement. The Yaxcopoil-1 and M0077A boreholes were continuously cored from about 400m to 1511 and 1335m, respectively and sampled distinct crater structures. Studies provide constraints on the crater formation, crustal deformation, lateral/vertical displacement, ejecta emplacement and crater collapse. Impact breccias are heterogeneous materials, with clasts of melt, carbonates and basement in carbonate-rich and melt-rich matrix. The lower breccias were emplaced by high-temperature basal surges, followed by collapse of the impact plume and lateral curtains. The upper breccias are reworked deposits of the post-collapse stage. The crater formed a depositional basin, filled with sediments that preserve records of sea level and sediment transport across the platform. Core analyses and scans provide constraints on the structure, stratigraphy, textures, mineralogy, deformation and hydrothermal alteration. Studies show the usefulness of continuous coring and core analyses to constrain the crater formation, impact deformation, ejecta and impact dynamics. Article geologica-acta@geo3bcn.csic.es Thu, 20 Feb 2025 14:00:00 GMT https://doi.org/10.1344/GeologicaActa2025.23.4 Shahab M., Ali L. & Alshehri F. (2025).- Integrated remote sensing, petrographic and mineralogical techniques for mapping of marble deposits in the vicinity of the ophiolite sequence in North Pakistan.- Marble, a high-pressure and high-temperature metamorphic rock primarily composed of calcium carbonate (CaCO3) and calcium magnesium carbonate (CaMgCO3), has been utilized extensively by ancient civilizations for various architectural purposes globally. The expansion of marble production during the 19th century facilitated its widespread use, with major quarries emerging in various regions, notably China, India, Italy, and Turkey. Despite its historical significance and economic importance, mapping and identifying marble deposits in remote and inaccessible areas remain challenging. This study presents an integrated approach utilizing advanced remote sensing techniques for mapping carbonate lithologies in the Northwest Mohmand District, Khyber Pakhtunkhwa, Pakistan. By employing Advanced Spaceborne Thermal Emission and Reflection Radiometry (ASTER) imaging coupled with Iterative Adaptive Reweighted Regression (IARR), Principal Component Analysis (PCA), Minimum Noise Fraction (MNF) and Spectral Angle Mapper (SAM) classification techniques, we processed and analyzed the ASTER images using the Environment for Visualizing Images (ENVI) software. Subsequently, Geographic Information Systems (GIS), ArcMap, and ArcScene software were used for spatial analysis and model generation. Validation of the results was conducted through extensive fieldwork, X-Ray Diffraction (XRD), and petrographic analysis. The XRD and petrographic data corroborated the findings derived from the classified ASTER imagery, confirming the presence of significant concentrations of dolomite and calcite, which are indicative of carbonate deposits. The integration of these techniques underscores the efficacy of remote sensing as a viable tool for identifying and mapping mineralized zones in remote locations.The findings of this study have significant implications for Pakistan's marble industry, particularly in Khyber Pakhtunkhwa, Punjab, and Baluchistan, where an estimated 300 million tons of marble reserves exist. Leveraging remote sensing techniques, this research contributes to the delineation of valuable marble resources and facilitates recommendations for targeted exploration activities in the Mohmand area and beyond. Article geologica-acta@geo3bcn.csic.es Wed, 19 Feb 2025 14:00:00 GMT https://doi.org/10.2478/mipo-2025-0002 Kukula A., Matusiak-Malek M., Mikrut J., Ntaflos T. and Johansson L. (2025).- Syn-volcanic melt-rock reactions recorded in peridotitic xenoliths from Scania, S Sweden. Peridotite xenoliths from Scania (S Sweden), brought to the surface by Mesozoic basanitic magmas, provide insights into the lithospheric mantle underlying the East European Craton. During their ascent, some of the entrained xenoliths were infiltrated by a Si-undersaturated melt. The infiltration triggered orthopyroxene dissolution and the formation of fine-grained olivine, clinopyroxene and Si-rich glasses (trachytic/trachydacitic and dacitic). The latter interacted with clinopyroxene and/or spinel creating spongy rims of various thicknesses (from few to hundreds of µm). The reactions varied in intensity and effect depending on the distance from the xenolith margin and the duration of the reaction time. At the outer parts of xenoliths, intense reactions dissolved orthopyroxene entirely, forming spongy rims on spinel and clinopyroxene, while inner sections showed limited reactions, primarily between mafic melts and orthopyroxene. The local reheating and melting of fine-grained aggregates during the ascent of xenoliths resulted in the formation of a hydrous, high-Mg, glass-like phase. Article irena.brunarska@uj.edu.pl Wed, 19 Feb 2025 10:00:00 GMT https://doi.org/10.2110/carnets.2025.2505 Bruno R.C. Granier, Emmanuel Robert & Joanaitz Pérez-Malo.- The Aptian-Albian of the Costa Blanca (SE Spain): Implications for identifying the Aptian/Albian boundary in the neritic zone within the Tethys realm.- The Aptian-Albian interval of the Costa Blanca (SE Spain) has been studied to provide new insights into the evolution of the neritic domain of carbonate platforms in the Tethys. Three areas have been re-examined: Serra Gelada, Puig Campana, and Cabeçó d'Or. The biozonations of large benthic foraminifers (LBF) have been revised based on ammonite biostratigraphy. Updated ammonite datings and stratigraphic revisions reveal that several LBF and calcareous algae (CA) taxa previously attributed to the late Aptian actually originated in the early Albian. These findings correct and refine the calibration of LBF and CA biozones and ranges with standard ammonite zones. Furthermore, the identification of a significant local hiatus during the middle Albian at Cabeçó d'Or is likely linked to halokinesis. Article carnetsgeol@rediris.es Sat, 15 Feb 2025 17:06:49 GMT https://doi.org/10.2110/carnets.2025.2504 Felix Schlagintweit, Yiwei Xu & Shijie Zhang.- Calcareous green algae (Dasycladales, Halimedaceae) from the Upper Cretaceous of the western Tarim Basin, NW China: Systematic palaeontology, microfacies, and palaeobiogeographic significance.- Few stratigraphical and micropalaeontological data are available from Upper Cretaceous shallow-water marine carbonates of the southwestern Tarim Basin, western China. The present study provides new data about the microfauna and calcareous algae of the Cenomanian-Turonian Kukebai Formation and the Campanian Yigeziya Formation. The investigated bioclastic carbonates yield a rather poorly diversified microfauna (benthic foraminifers) contrasting with a relatively well diversified assemblage of dasycladalean green algae comprising 16 taxa. For several taxa, the available material does only allow for an open taxonomic treatment. A new species is described herein as Morelletpora sinica. These calcareous algae are supplemented by debris of halimedacean algae (Arabicodium? sp.). Occurrences of calcareous algae and larger benthic foraminifers in Cenomanian and Campanian carbonates coincide with two major transgressions reported from the Tarim Basin. The observed faunal and phycological elements indicate a direct connection between the Neotethys and the Tarim epicontinental sea. The lack of several typical Cenomanian (e.g., alveolinoids, orbitolinids) and Campanian larger benthic foraminifers in the studied material is striking. Article carnetsgeol@rediris.es Mon, 03 Feb 2025 17:02:09 GMT https://doi.org/10.1344/GeologicaActa2025.23.2 Marín M., Carola E., Beamud E., Bover-Arnal T., López-Blanco M., Garcés M., Roca E., Costa E., Ferrer O. & Cabrera L. (2025).- Paleogene kinematics of the central Catalan Coastal Ranges: temporal constraints from magneto-chronology and provenance analysis in synorogenic deposits in the SE margin of the Ebro Basin (NE Spain).- The precise determination of the tectonic deformation timing such as thrust emplacement has always been a challenge for understanding the evolution of fold-and-thrust belts. In the Catalan Coastal Ranges, this issue has traditionally been addressed through the mapping and the analysis of the syn-tectonic successions preserved in the SE margin of the Ebro Basin. However, the age of the Paleogene contractional structures located towards the hinterland and responsible of the inversion and uplift of the inherited Mesozoic structure remained uncertain due to the lack of preserved syn-kinematic strata in these areas. With the aim of better understand the contractional evolution of the area during the Paleogene, this work presents a tectono-stratigraphic analysis approach that combines structural reconstructions, provenance analysis and magnetostratigraphic dating in well-exposed synorogenic sediments in the central SE margin of the Ebro Basin. The results of the study allow to establish the precise age of the main contractional structures present in the central Catalan Coastal Ranges. The combined analysis has revealed that: i) the inversion of the Montmell-Vallès Faults System started in the Bartonian and continued up to the late Priabonian, and ii) the emplacement of the Gaià-El Camp Thrust and the formation of the Cabra-Carme Anticline took place from early to late Priabonian and was the responsible of the sudden increased of the sedimentation rates. A later decrease of the sedimentation rates during late Priabonian (chron C15n) has been interpreted as the prelude of the end of the Paleogene compressional phase in the area. Article geologica-acta@geo3bcn.csic.es Sat, 01 Feb 2025 12:00:00 GMT https://doi.org/10.1344/GeologicaActa2025.23.1 García-Penas Á., Zamora S., Moreno-Bedmar J.A., Calvín P. & Aurell M. (2025).- Latest Barremian - early Aptian chronostratigraphy and sedimentary evolution of the northwestern Maestrat Basin.- Some aspects on the age and correlation of the upper Barremian-lower Aptian stratigraphic units of the NW Maestrat Basin were uncertain prior to this study, due to the differing lithostratigraphy of the marginal Oliete subbasin compared to the more depocentral Galve and Morella subbasins. New magnetostratigraphic, ammonite and sedimentological data presented in this study refine the age and sequence stratigraphy of the upper Barremian-lower Aptian succession, enabling a direct and precise correlation across these subbasins. Three third-order TR sequences are identified. The lower boundary of Sequence 1 corresponds to a transgressive surface found on top of the continental red beds of the lower Morella Fm. These beds are equivalent in age to the continental succession of the upper Blesa Fm.(Oliete subbasin). The boundary between the M1 and M0r magnetozones (latest Barremian) is found above this surface, in the lower part of the Alacón Fm. Sequence 1 includes the lower part of the Alacón Fm., which passes basinwards to the upper Morella and Xert formations. Sequence 2 corresponds to the upper part of the Alacón Fm and basinwards to the Cap de Vinyet and Barra de Morella members of the Forcall Fm. The boundary between the M0r and C34n magnetozones (earliest Aptian) is found towards the lowermost part of Sequence 2. Sequence 3 includes the Josa Fm. and its offshore equivalents, the Morella la Vella Mb. and the Villarroya de los Pinares Fm. Additionally, the overall facies distribution in successive depositional stages is reconstructed, describing the lateral transition from marginal protected to open marine areas. The improved chronostratigraphic framework presented here will enable more accurate correlations with other subbasins of the Maestrat Basin, and the reconstructed sedimentary evolution may be useful for the interpretation of other Lower Cretaceous successions of the Tethys. Article geologica-acta@geo3bcn.csic.es Sat, 01 Feb 2025 14:00:00 GMT https://doi.org/10.2478/mipo-2025-0005 Topolska J. (2025).- Long story encrypted in a small grain – zircon from meta-andesite in the Lower Köli Nappes reveals a complex history of the Virisen Arc Terrane, Scandinavian Caledonides, Sweden.- Tracking trace chemical alterations in biogenic apatite – improvements in tooth sample preparation for experimental approach. Studying the properties of hard tissues, such as bones or teeth, often requires an experimental approach that enables the mechanisms observed in clinical settings to be explained or supports the safe planning of clinical trials. This paper compiles some methodological insights on the proper preparation of biogenic apatite found in human teeth for in vitro studies. These insights were gathered through experimental work and a review of some literature related to in vitro studies on the impact of metal orthodontic appliances on the chemical and crystallographic properties of dental enamel. Article irena.brunarska@uj.edu.pl Sat, 20 Jan 2024 10:00:00 GMT https://doi.org/10.2110/carnets.2025.2503 Antoine Pictet, Bruno Hugon & Gustavo Pierangelini.- Itierella melognensis n.gen., n.sp., and Paradicostella hautevillelompnesensis n.gen., n.sp. (Ammonoidea, Neocomitidae, Neocomitinae), two new upper Valanginian trituberculated ammonoids from the Jura Mountains, eastern France.- Several ammonoid specimens from the upper Valanginian (Lower Cretaceous) sedimentary succession of Hauteville-Lompnes, Department of Ain, eastern France, are assigned to the new genera and species Itierella melognensis n.gen., n.sp., and Paradicostella hautevillelompnesensis n.gen., n.sp. Specimens collected in the past were misidentified as Acanthodiscus Uhlig, 1905, and erroneously assigned to the lowermost part of the Hauterivian stage. The revision of the Marnes de Mélogne, along with the collection of a rich associated ammonite fauna, allows Itierella to be recognized as a latest Valanginian homeomorphic form of the genus Acanthodiscus, and Paradicostella as closely related to the genus Dicostella Busnardo, 1966. The Marnes de Mélogne are revised as mostly belonging to the upper Saynoceras verrucosum to Criosarasinella furcillata ammonite zones (uppermost Valanginian), while their uppermost metre is assigned to the Acanthodiscus radiatus Zone (lowermost Hauterivian). Article carnetsgeol@rediris.es Wed, 15 Jan 2025 16:58:42 GMT https://doi.org/10.2110/carnets.2025.2502 Bruno R.C. Granier, José Miguel Andreu Rodes, Mohamed Benzaggagh, Joachim Blau, Éric Böker, Antonio Estévez Rubio, Bruno Ferré, Bernard C. Lambert, Agostino Marini, Eric Monteil, Stéphane Reboulet & Aurélien Virgone.- Rectifying a substantial biostratigraphic error: There are no Hauterivian calpionellids in Busot (Alicante, Spain).- Earlier misidentifications of ammonites from Busot (SE Spain) led to two incorrect hypotheses regarding calpionellids, which are today attributed to the Calpionellopsis Zone (D) of the upper Berriasian. The first hypothesis suggested that some calpionellid species survived into Hauterivian times, while the second hypothesis proposed that these calpionellids were reworked into Hauterivian strata. However, the revision of the ammonitic material collected in 1993-1994, along with the study of new material collected in 2024, suggests a late Berriasian age, as the ammonite assemblages likely correspond to the Fauriella boissieri and Tirnovella alpillensis Standard Ammonites zones. Nannofossil assemblages and the presence of Octahedronoides tethysianus further support this dating. This reassessment calls for a reexamination of claims regarding the occurrence of calpionellids in strata younger than the Valanginian in the literature. Article carnetsgeol@rediris.es Wed, 25 Dec 2024 16:53:06 GMT https://doi.org/10.2110/carnets.2025.2501 Arthur Saller.- Aragonite neomorphism via intrafabric dissolution and calcite precipitation, not thin films.- Since the 1970's, aragonite neomorphism (conversion of aragonite to calcite with partial retention of original internal structure) has been attributed to thin diagenetic films, often in meteoric water. Pleistocene material from Enewetak, the Bahamas and eastern Yucatan show the transition from aragonite to calcite 'in progress'. Original aragonitic material includes coral, Halimeda, molluscs (especially gastropods) and ooids. In all three areas, aragonite commonly shows partial intrafabric dissolution. In many cases, calcite crystals grew over that highly microporous aragonite to create calcite with partial retention of the original depositional fabric, creating neomorphosed (calcitized) aragonite. Geochemical data support this scenario. Carbon and oxygen isotopic compositions of the neomorphic calcites are similar to sparry meteoric calcite cements indicating crystals precipitated from similar waters as the cements. Stable carbon isotopes and Mg concentrations in neomorphic calcites are different from their aragonitic precursors and are not consistent with the thin-film model, which assumes a semi-closed system. Approximately 40 of the 95 Pleistocene Enewetak samples have aragonite with intrafabric dissolution adjacent to calcitized (neomorphic) aragonite. Neomorphosed (calcitized) aragonite was not observed immediately adjacent to unaltered aragonite (i.e., separated by what would have been a thin film) in any Enewetak samples. This supports aragonite neomorphism by a two-stage process (intrafabric dissolution followed by calcite precipitation) rather than by thin films. Variations in concentration of inclusions in neomorphosed aragonite are similar to variations of relict material in aragonite with partial intrafabric dissolution and span a continuum from abundant aragonitic inclusions in neomorphic spar to inclusion-free calcite cement. Article carnetsgeol@rediris.es Fri, 20 Dec 2024 16:42:41 GMT https://doi.org/10.2110/carnets.2024.2413/index.html U. Kağan Tekin, Bilal Sarı, Alaettin Tuncer, Kaan Sayit, Cengiz Okuyucu & Çağrı Güzgün.- Radiolarian and planktonic foraminiferal biochronology of the Soğukçam Limestone Group, Elmadağ Olistostrome, and Unaz Formation (Ankara region, central Türkiye): Insights into the Cretaceous evolution of the Sakarya Continent and overlying units.- The Ankara region (central Türkiye) comprises a part of the Sakarya Terrane and the accretionary remnants inherited from the Izmir-Ankara-Erzincan (IAE) branch of the Northern Neotethys. The Sakarya Terrane is characterized by a pre-Jurassic basement overlain by Jurassic-Cretaceous sedimentary assemblages, collectively known as the Sakarya Continent Cover. In this study, we aim to elucidate the Jurassic-Cretaceous evolution of the Sakarya Terrane through detailed geological mapping in the regions of Haymana, Yakacık, north of Alagöz and west of Memlik, located to the west and southwest of Ankara city, central Türkiye. By analyzing radiolarian and planktonic foraminiferal assemblages, we provide precise dating for three key lithological units: the Soğukçam Limestone Group (part of the Sakarya Continent Cover), the Elmadağ Olistostrome, and the Unaz Formation (from the overlying units). The oldest rock unit exposed in the Haymana region, south of Ankara city, is the Bilecik Limestone Group, consisting of Tithonian to lower Berriasian platform carbonates. A drowning unconformity separates the Bilecik Limestone Group from the overlying middle Berriasian-uppermost Albian Soğukçam Limestone Group, which has been elevated to 'group' status in this study. The Soğukçam Limestone Group is subdivided into two formations -the Seyran Formation and the Akkaya Formation- separated by a disconformity surface. The Seyran Formation, at the base, consists of middle Berriasian limestone breccia in a micritic pelagic matrix, and upper Berriasian-lower Aptian micritic clayey, cherty pelagic limestones with abundant and diverse radiolarians in its upper part. The disconformity between the Seyran and Akkaya formations represents a small depositional gap corresponding to the middle to late Aptian. The lower part of the Akkaya Formation contains lower to middle Albian debris flow deposits while the upper part is composed of clayey pelagic limestones rich in glauconite and planktonic foraminifers, dating to the latest Albian. Overall, the Akkaya Formation is roughly assigned to the Albian stage. The Akkaya Formation within the Soğukçam Limestone Group is unconformably overlain by the Coniacian Elmadağ Olistostrome, which also covers the ophiolitic mélange of the IAE Ocean (containing Turonian radiolarian blocks) to the west of the Memlik region. The basal part of the Elmadağ Olistostrome is characterized by an unstratified, loosely-packed, gray- to beige-colored carbonate matrix, while its upper part features stratified, highly-sheared gray- to beige-colored clayey carbonate/marl matrix with embedded carbonate blocks. These blocks, dated through radiolarians and planktonic foraminifers, range from the early Callovian to Coniacian. These blocks, observed in the Haymana, north of Alagöz, and Yakacık regions, primarily originated from the underlying Soğukçam Limestone Group. The Elmadağ Olistostrome was likely deposited in a peripheral foreland flysch basin, resembling trench-like settings, in front of the southward-moving nappes derived from the Neotethys Intra-Pontide Ocean. This olistostrome is unconformably overlain by the Unaz Formation, which represents the lowermost unit of the fore-arc basin within the Galatean Arc and is present in all four studied regions. The Unaz Formation mainly consists of thin-bedded, gray- to red-colored clayey limestones with abundant planktonic foraminifers, along with red- to pink-colored marls. In the northern part (west of Memlik), the Unaz Formation also includes basal clastics. Based on its characteristic planktonic foraminiferal assemblages, the formation is dated to the late Santonian and correlates well with the type locality in the Pontides, northwestern Türkiye. Following this sequence, a brief period of continental arc magmatism occurred in the Santonian-Campanian, accompanied by the deposition of fore-arc sediments (the Haymana Formation, consisting of clastics) during the Campanian-Maastrichtian interval. In this study, an abundant, well-preserved, and diverse radiolarian microfauna (146 taxa, including fourteen new species and four new subspecies from the early Hauterivian to early Aptian, Early Cretaceous) were recovered from the clayey micritic limestones of the Seyran Formation in the Soğukçam Limestone Group. The vertical distributions of these radiolarians and their age correlations with previous studies are also documented. Article carnetsgeol@rediris.es Sun, 15 Dec 2024 16:38:07 GMT https://doi.org/10.5474/geologija.2024.016 Bavec Š, Cerar S., Gaberšek M. & Pogačnik Ž.- Geochemical distribution of elements in the environmental media from the surroundings of open pit areas.- The results of geochemical investigations - carried out within the framework of the European project LIFE IP RESTART - in the degraded areas of the Kopriva (deposit of natural stone-limestone) and Lipovški vrh (deposit of limestone for industrial purposes) open pits are presented. There test sites of the installation of secondary raw materials (a mixture of recycled materials and mineral raw materials) with the aim of revitalizing degraded surfaces are planned. The main goal of this study is to define the baseline geochemical distribution of elements in environmental materials (rocks, soil, stream sediment and surface water) for the purpose of monitoring the potential environmental impacts of installed secondary raw materials. In rocks Ca content predominates due to the geological setting (predominantly limestone) of the studied areas. According to the legislative guidelines for soil, exceedances have been found for Pb in one sample (origin can be natural or anthropogenic) and Ni in two samples (presumably natural origin) from the area of Kopriva. In the area of Lipovški vrh in the stream Suhi Potok, higher contents of Mg, Na, Sr, Ca, Mn and S occur in the downstream sediment compared to upstream sediment. It is assumed higher contents occur due to anthropogenic contribution of carbonate material along the stream (washing of materials from nearby open pit and road). In the surface water of Suhi Potok, higher concentrations of S, Sr, B, U and Zn were determined. However, the concentrations did not exceed the legislative guidelines. Article mateja.gosar@geo-zs.si Thu, 12 Dec 2024 16:00:00 GMT https://doi.org/10.2110/carnets.2024.2412/index.html Felix Schlagintweit.- A new subfamily classification of the Coskinolinidae Moullade, 1965, Middle Jurassic-Paleogene Larger Benthic Foraminifera.- The Coskinolinidae are a family of Middle Jurassic to Paleogene, typically orbitoliniform, Larger Benthic Foraminifera (LBF) characterized by a pseudokeriothecal wall structure. The type genus, Coskinolina Stache, 1875, lacks an exoskeleton (i.e., beams, rafters), resulting in an undivided marginal chamber zone. However, other taxa within the family, such as the Upper Cretaceous Lepinoconus Cruz-Abad et al., 2017, or the Paleogene Coleiconus Hottinger & Drobne, 1980, are genera with vertical partitions (beams) that subdivide the marginal chamber zone. In the currently accepted classification of agglutinated benthic foraminifera, the nature of the exoskeleton is a criterion for distinction at subfamily level, e.g., Cyclamminidae Marie, 1941. Thus, here, the presence or absence of an exoskeleton in the marginal chamber lumen is treated as a criterion at the subfamily level within the classification of the Coskinolinidae, leading to a division into two subfamilies: the Coskinolininae Moullade, 1965 (lacking an exoskeleton), and the newly proposed Coleiconinae subfam. nov. (with an exoskeleton of vertical partitions), as exemplified by Coleiconus Hottinger & Drobne, 1980. Article carnetsgeol@rediris.es Sat, 30 Nov 2024 16:30:26 GMT https://doi.org/10.2110/carnets.2024.2411/index.html Oldřich Fatka.- Extraordinary trilobite collected by František Pošepný discovered after 140 years.- This extraordinary specimen, a well-preserved articulated thorax of a large specimen of the middle Cambrian paradoxidid trilobite Paradoxides (Hydrocephalus) minor (Boeck, 1827), was collected by the notable geologist František Pošepný during an excursion to the Hřebeny mountain range, Czech Republic, in the 1890s, and was thought to have been lost for nearly 140 years. The trilobite originates from the Brdlavka locality, one of the easternmost outcrops of the Jince Formation. There is no fossil collected at this locality housed in institutional and private collections. The recent discovery of this fossil in the Geological Pavilion of the Technical University of Ostrava, Czech Republic, enabled its assignment to the common species Paradoxides (Hydrocephalus) minor (Boeck, 1827). This species confirms the occurrence of the middle levels of the middle Cambrian Jince Formation at the Brdlavka locality. Article carnetsgeol@rediris.es Thu, 31 Oct 2024 16:24:12 GMT https://doi.org/10.2110/carnets.2024.2410/index.html Simon F. Mitchell, Edward Robinson, Ercan Özcan , Mark M. Jiang & Natalie Robinson.- A larger benthic foraminiferal zonation for the Cenozoic of the Americas.- The Cenozoic of the Americas does not have a zonation based on Larger Benthic Foraminifera (LBF) unlike the Tethys where there is a shallow-water benthic zonation. Although there were faunal exchanges, the different evolutionary patterns between the Americas and the Tethys require separate zonations. We have calibrated LBF, stratigraphic distributions and events in the Americas using calcareous nannoflora (Paleocene-Eocene), planktic foraminifers (Oligocene-Miocene) and published strontium (Sr) isotope values. We define 29 zones spanning the Paleocene to Recent based on changing LBF assemblages and evolving lineages, with some zonal boundaries related to global or local palaeoenvironmental events. This will allow correlation across carbonate platforms in the tropical Americas at a higher resolution than previously possible. Article carnetsgeol@rediris.es Thu, 31 Oct 2024 16:22:18 GMT https://doi.org/10.2110/carnets.2024.2409/index.html Vitaly Dernov.- Shell injuries in Densepustula Lazarev, 1982, Pennsylvanian productidine brachiopod from the Donets Basin, Ukraine.- Nine injured ventral valves of productidine brachiopods belonging to the genus Densepustula Lazarev, 1982, from the Mospyne, Smolyanynivka, Belaya Kalitva, and Kamensk formations (Upper Bashkirian-lower Moscovian, Lower and Middle Pennsylvanian) of the Donets Basin (eastern Ukraine) were studied. Three morphological types of damage traces have been recognized: Type A) longitudinal, sublongitudinal, and transversal thin straight or sinuous furrows, about 5-7 mm long and 0.5-1.5 mm thick; Type B) rounded and ellipsoidal pits, about 3-4 mm in diameter, located on the umbo, the anterior margin of the ventral valve, and the lateral slopes of the ventral valve; and Type C) irregularly-shaped dimples on the anterior margin and in the sulcus, 2-3 mm in size. These injuries are present on 9 out of 61 (15%) of ventral valves studied, but entirely absent from dorsal valves (0 out of 25). The most likely producers of these damage traces are cartilaginous fishes and parasites of unclear affinity. Article carnetsgeol@rediris.es Fri, 20 Sep 2024 16:26:49 GMT https://doi.org/10.2110/carnets.2024.2408/index.html Alessandro Freschi & Simone Cau.- Tooth marks of the Great White Shark from a Pliocene outcrop of the Northern Apennines (Castell'Arquato, Italy).- We describe and analyze a rib fragment of a small cetacean from the Castell'Arquato Plio-Pleistocene Basin (Northern Apennines, Italy) that displays various tooth marks featuring parallel striations similar to those left by the serrated tooth of the extant white shark, Carcharodon carcharias. The discovery locality, known as ''Buca della Balena'', was an inner-shelf marine setting where sharks may have scavenged on drifting cetacean carcasses in Piacenzian times. The high number of marks found on the small bone fragment suggests multiple bites by one or more shark individuals. The rib fragment studied is one of the few osteological specimens from the Pliocene of the Mediterranean Basin to preserve white shark tooth marks. Article carnetsgeol@rediris.es Wed, 24 Jul 2024 16:11:53 GMT https://doi.org/10.2110/carnets.2024.2407/index.html Bruno R.C. Granier.- Octahedronoides tethysianus n.gen., n.sp., enigmatic clusters of microspheres at the Jurassic-Cretaceous transition.- In the literature, numerous accounts exist of microspheres scattered in the pelagic environments of the Tethys realm at the Jurassic-Cretaceous transition. These microspheres are commonly associated with genera such as Cadosina, Colomisphaera, or Stomiosphaera, and attributed to calcareous dinocysts. On the other hand, there are few records of the microsphere, initially described as Cadosina minuta Borza, 1980, which are arranged in small clusters, likely comprising six cells. This distinctive grouping and its architecture preclude attribution to the calcareous dinocysts. A new genus and a new species (as Octahedronoides tethysianus n.gen., n.sp.) are introduced to define these clusters of leiospheres, which are here reascribed to the acritarchs. Article carnetsgeol@rediris.es Wed, 08 May 2024 17:57:01 GMT https://doi.org/10.2110/carnets.2024.2406/index.html Dany Azar, Sibelle Maksoud, Di-Ying Huang, Mounir Maalouf & Chen-Yang Cai.- A new fossil psychodomorphan fly from Lower Barremian Lebanese amber elucidates the relationship of the Tanyderinae stat. nov. within the Psychodidae.- A new species, Nannotanyderus granieri sp. nov., belonging to the Tanyderidae (Diptera, Nematocera), from Lower Barremian amber of Bqaatouta (Lebanon), is characterized, described, figured, and its taxononomic position discussed. The possible confusion regarding the attribution of new fossils to either the Tanyderidae or the Psychodidae, in addition to the results of recent molecular phylogenies, have led us to re-evaluate the taxonomic position of the Tanyderidae and to consider it as a subfamily within the Psychodidae. The fossil described herein is a tiny tanyderine sensu nov. species, and the second one belonging to the genus Nannotanyderus from Lebanese amber. A tentative molecular phylogeny of recent Psychodidae and an exhaustive catalogue of fossil Tanyderinae stat. nov. are provided. Article carnetsgeol@rediris.es Mon, 01 Apr 2024 18:02:31 GMT https://doi.org/10.2110/carnets.2024.2405/index.html Bruno R.C. Granier & Philippe Lapointe.- The Kalkowski Project - Chapter VI. A panorama of synsedimentary broken ooids.- Broken ooids are known to occur in both aragonitic and calcitic ooids with radial fabrics. In the literature, it has been suggested that synsedimentary breakage could be related to attrition/mechanical impacts, hypersalinity, or desiccation. However, this paper demonstrates that none of the aforementioned phenomena provides a valid explanation. Although the exact process remains unknown (potentially involving some synsedimentary recrystallization), it is shown that: 1) the breakage is genetically linked to the radial fabrics; 2) the ratio of ooid breakages increases with the relative thickness of the radial cortical layers; 3) fracture growth in broken ooids proceeds centripetally. Article carnetsgeol@rediris.es Thu, 29 Feb 2024 17:53:56 GMT https://doi.org/10.2110/carnets.2024.2404/index.html Artur Artur, Gabriella da C. Pereira, Paulo R. de O. Costa & Mercedes Okumura.- A new record of ground sloth in the Ribeira de Iguape valley, southeastern Brazil.- In the early 1980s, an assemblage of extinct and extant vertebrates was collected from the Abismo Ponta de Flecha, a vertical cave in southern São Paulo, Brazil, for archaeological, geological, and paleontological analyses. While materials identified as ground sloths have been referenced in earlier publications, they have never been thoroughly described. In this study, we provide the first detailed description of a large, previously unidentified taxon found in Brazil, interpreted herein as belonging to the family Nothrotheriidae. Although direct dating of the specimen was not possible, other dated occurrences from the Ribeira de Iguape Valley suggest that it may have inhabited the region during the Late Pleistocene, coinciding with the local presence of a dense forest cover. Article carnetsgeol@rediris.es Wed, 31 Jan 2024 17:53:18 GMT https://doi.org/10.2110/carnets.2024.2403/index.html Bruno R.C. Granier & Philippe Lapointe.- The Kalkowsky Project - Chapter V. Asymmetric ooids from the Yacoraite Formation (Argentina).- Asymmetric ooids are documented in a brackish Maastrichtian to Danian paleolake in NW Argentina. Their distinctive asymmetric growth pattern is likely related to an uneven distribution of the Extracellular Polymeric Substances (EPS) around the coated allochem, within which calcite fibers (i.e., the 'fibrite') have grown. This pattern is unlikely to be mistaken for that of other 'eccentric' ooids, such as wobbly ooids, spiny ooids, hiatus ooids, half-moon ooids, 'broken' ooids sensu lato, or collapsed oomolds (referred to as 'distorted' ooids). Article carnetsgeol@rediris.es Sat, 20 Jan 2024 18:19:36 GMT https://doi.org/10.2110/carnets.2024.2402 Ricardo L.M. Azevedo, Rogério L. Antunes, Mauro D.R. Bruno, Thomas R. Fairchild & Dimas Dias-Brito.- The Central South Atlantic: The origin of its waters, its evolution and effects beyond.- The primitive sea that occupied the Central South Atlantic (CSA), part of the intra-Gondwana rift during the Early Cretaceous, allowed precipitation of an extensive and thick layer of evaporites, the Ibura Salt, followed by the deposition of a prominent Albian carbonate package. Although the shallow platform facies do not contain classical benthic Tethys markers, the pelagic open sea carbonates are essentially dominated by planktonic elements coming from the Tethys Realm. This condition led some researchers to think that Tethys waters also contributed to salt formation, an idea that clashes with the geotectonic model of northward separation of Africa and South America and ingression of predominantly Austral marine waters. Now, a new controversy arises as to the age of this salt layer when trying to position bio-events and lithological and chemostratigraphic markers from these rocks with respect to established data for the Global Boundary Stratotype Section and Point for the Aptian/Albian boundary (GSSP-Alb). Biochronostratigraphic information on planktonic foraminifera points to an Aptian age as opposed to the earliest Albian traditionally accepted for the carbonate section that overlies the giant salt layer. On the other hand, stratigraphic and geochronological data suggest an age of 113 Ma for the base of the salt, very near to the 113.2 ± 0.1 Ma arbitrated for the GSSP-Alb. In this study, we adopt the base of the evaporite bed as the Aptian/Albian boundary in the CSA, Equatorial South Atlantic (ESA), and northeastern Brazilian interior basins (BNE) as well. Based on these criteria, a broad review and the integration of available information have led to new interpretations regarding the earliest phase of these segments of the South Atlantic and adjacent areas. Initially, during the Aptian-Albian transition, an ephemeral interior sea within Brazil, drawing its waters from the north, would have contributed to salt deposition in the intra-Gondwana rift (evaporitic stage of the CSA). Afterward, but still within the earliest Albian, the evaporitic system evolved into a carbonate gulf when the northern barrier, the Exception Zone (EZ), disappeared. The lagoonal circulation pattern that then formed in the CSA created a hypersaline and warm outflow plume that swept across the marine bottom of the ESA and part of the Tethys Sea. Paleoceanographic events registered at Site 545, Mazagan Plateau, support this new hypothesis and illustrate the potential complexity of correlation of organic-rich deposits in which local influences have been greater than global ones. This long, narrow, and continuous carbonate gulf disappeared at the end of the Albian with the arrival of southern waters from the Meridional South Atlantic (MSA), and the South Atlantic became consolidated as a proto-ocean. Article carnetsgeol@rediris.es Sat, 20 Jan 2024 18:17:18 GMT https://doi.org/10.2110/carnets.2024.2401 Hanane Bahaj, Nadia Barhoun, Naima Bachiri Taoufiq, Jihad Rahmouna, Soukaina Targhi, Naima Berry, Jean-Pierre Suc & Speranta-Maria Popescu.- Paleoenvironmental changes preceding the onset of the Messinian salinity crisis in the western Mediterranean Sea (pre-evaporitic Messinian of the Melilla-Nador Basin, NE Morocco).- In order to contribute to the understanding of the evolution of marine and continental environments, preceding the onset of the Messinian salinity crisis in the western Mediterranean, we conducted an integrated study of the pre-evaporitic Messinian sedimentary series in the Melilla-Nador basin. Three sections have been carried out in the marl-diatomite series and were the subject of a detailed biostratigraphic and palynological study. The study of planktonic foraminifera, pollen, dinocysts, and palynofacies allowed us to characterize the evolution of these environments. From 6.83 to 6.52 Ma, the marine environment was relatively open, calm, probably subject to the action of upwellings and received periodic continental inputs. Starting 6.52 Ma, the abundance and diversity of planktonic foraminifera decreased. Continental inputs gradually dominate, alternating with marine ones, and reflecting a succession between proximal and distal neritic environments. The surface water conditions were warm. After 6.35 Ma, began the degradation of marine conditions. The continental environment shows an open vegetal landscape dominated by herbaceous plants, reflecting a tropical to arid subtropical climate, slightly less dry than that of the South Rifian Corridor. This study confirms the existence of several parameters that contributed to the deposition of the cyclical marl-diatomite series: on the one hand, the hot and dry climate favored the reduction of the plant landscape and therefore erosion (continental inputs); on the other, the tectonics (volcanism and uplift). Article carnetsgeol@rediris.es Wed, 17 Jan 2024 18:13:15 GMT https://doi.org/10.26879/1276 Felix Schlagintweit.- Challenges in orbitolinid identification and biostratigraphic consequences: an Aptian example.- The much-cited importance of Orbitolinidae in biostratigraphy depends on the species and time-interval under consideration. In any case, correct species identification is of primary importance as the basis for drawing conclusions. This task is best achieved in an assemblage where centered sections (axial and transverse) showing all details of the complex megalospheric embryo are available. Difficulties in the correct interpretation of oblique sections is exemplified by an example from the Aptian of Turkey, respectively Praeorbitolina versus Mesorbitolina. Resulting differences in species determination not only has an impact on age interpretation, but also associated geologic-tectonic conclusions, as well as basic taxonomic data (e.g., stratigraphic ranges, statistics on stage diversities). Article mihaela.gradinaru@unibuc.ro Thu, 14 March 2024 13:03:01 GMT https://doi.org/10.2110/carnets.2024.2405 Bruno R.C. Granier & Philippe Lapointe.- The Kalkowski Project - Chapter VI. A panorama of synsedimentary broken ooids.- Broken ooids are known to occur in both aragonitic and calcitic ooids with radial fabrics. In the literature, it has been suggested that synsedimentary breakage could be related to attrition/mechanical impacts, hypersalinity, or desiccation. However, this paper demonstrates that none of the aforementioned phenomena provides a valid explanation. Although the exact process remains unknown (potentially involving some synsedimentary recrystallization), it is shown that: 1) the breakage is genetically linked to the radial fabrics; 2) the ratio of ooid breakages increases with the relative thickness of the radial cortical layers; 3) fracture growth in broken ooids proceeds centripetally. Article carnetsgeol@rediris.es Thu, 29 Feb 2024 17:53:56 GMT https://doi.org/10.2110/carnets.2024.2404 Artur Artur, Gabriella da C. Pereira, Paulo R. de O. Costa & Mercedes Okumura.- A new record of ground sloth in the Ribeira de Iguape valley, southeastern Brazil.- In the early 1980s, an assemblage of extinct and extant vertebrates was collected from the Abismo Ponta de Flecha, a vertical cave in southern São Paulo, Brazil, for archaeological, geological, and paleontological analyses. While materials identified as ground sloths have been referenced in earlier publications, they have never been thoroughly described. In this study, we provide the first detailed description of a large, previously unidentified taxon found in Brazil, interpreted herein as belonging to the family Nothrotheriidae. Although direct dating of the specimen was not possible, other dated occurrences from the Ribeira de Iguape Valley suggest that it may have inhabited the region during the Late Pleistocene, coinciding with the local presence of a dense forest cover. Article carnetsgeol@rediris.es Wed, 31 Jan 2024 17:53:18 GMT https://doi.org/10.2110/carnets.2024.2403 Bruno R.C. Granier & Philippe Lapointe.- The Kalkowsky Project - Chapter V. Asymmetric ooids from the Yacoraite Formation (Argentina).- Asymmetric ooids are documented in a brackish Maastrichtian to Danian paleolake in NW Argentina. Their distinctive asymmetric growth pattern is likely related to an uneven distribution of the Extracellular Polymeric Substances (EPS) around the coated allochem, within which calcite fibers (i.e., the 'fibrite') have grown. This pattern is unlikely to be mistaken for that of other 'eccentric' ooids, such as wobbly ooids, spiny ooids, hiatus ooids, half-moon ooids, 'broken' ooids sensu lato, or collapsed oomolds (referred to as 'distorted' ooids). Article carnetsgeol@rediris.es Sat, 20 Jan 2024 18:19:36 GMT https://doi.org/10.2110/carnets.2024.2402 Ricardo L.M. Azevedo, Rogério L. Antunes, Mauro D.R. Bruno, Thomas R. Fairchild & Dimas Dias-Brito.- The Central South Atlantic: The origin of its waters, its evolution and effects beyond.- The primitive sea that occupied the Central South Atlantic (CSA), part of the intra-Gondwana rift during the Early Cretaceous, allowed precipitation of an extensive and thick layer of evaporites, the Ibura Salt, followed by the deposition of a prominent Albian carbonate package. Although the shallow platform facies do not contain classical benthic Tethys markers, the pelagic open sea carbonates are essentially dominated by planktonic elements coming from the Tethys Realm. This condition led some researchers to think that Tethys waters also contributed to salt formation, an idea that clashes with the geotectonic model of northward separation of Africa and South America and ingression of predominantly Austral marine waters. Now, a new controversy arises as to the age of this salt layer when trying to position bio-events and lithological and chemostratigraphic markers from these rocks with respect to established data for the Global Boundary Stratotype Section and Point for the Aptian/Albian boundary (GSSP-Alb). Biochronostratigraphic information on planktonic foraminifera points to an Aptian age as opposed to the earliest Albian traditionally accepted for the carbonate section that overlies the giant salt layer. On the other hand, stratigraphic and geochronological data suggest an age of 113 Ma for the base of the salt, very near to the 113.2 ± 0.1 Ma arbitrated for the GSSP-Alb. In this study, we adopt the base of the evaporite bed as the Aptian/Albian boundary in the CSA, Equatorial South Atlantic (ESA), and northeastern Brazilian interior basins (BNE) as well. Based on these criteria, a broad review and the integration of available information have led to new interpretations regarding the earliest phase of these segments of the South Atlantic and adjacent areas. Initially, during the Aptian-Albian transition, an ephemeral interior sea within Brazil, drawing its waters from the north, would have contributed to salt deposition in the intra-Gondwana rift (evaporitic stage of the CSA). Afterward, but still within the earliest Albian, the evaporitic system evolved into a carbonate gulf when the northern barrier, the Exception Zone (EZ), disappeared. The lagoonal circulation pattern that then formed in the CSA created a hypersaline and warm outflow plume that swept across the marine bottom of the ESA and part of the Tethys Sea. Paleoceanographic events registered at Site 545, Mazagan Plateau, support this new hypothesis and illustrate the potential complexity of correlation of organic-rich deposits in which local influences have been greater than global ones. This long, narrow, and continuous carbonate gulf disappeared at the end of the Albian with the arrival of southern waters from the Meridional South Atlantic (MSA), and the South Atlantic became consolidated as a proto-ocean. Article carnetsgeol@rediris.es Sat, 20 Jan 2024 18:17:18 GMT https://doi.org/10.2110/carnets.2024.2401 Hanane Bahaj, Nadia Barhoun, Naima Bachiri Taoufiq, Jihad Rahmouna, Soukaina Targhi, Naima Berry, Jean-Pierre Suc & Speranta-Maria Popescu.- Paleoenvironmental changes preceding the onset of the Messinian salinity crisis in the western Mediterranean Sea (pre-evaporitic Messinian of the Melilla-Nador Basin, NE Morocco).- In order to contribute to the understanding of the evolution of marine and continental environments, preceding the onset of the Messinian salinity crisis in the western Mediterranean, we conducted an integrated study of the pre-evaporitic Messinian sedimentary series in the Melilla-Nador basin. Three sections have been carried out in the marl-diatomite series and were the subject of a detailed biostratigraphic and palynological study. The study of planktonic foraminifera, pollen, dinocysts, and palynofacies allowed us to characterize the evolution of these environments. From 6.83 to 6.52 Ma, the marine environment was relatively open, calm, probably subject to the action of upwellings and received periodic continental inputs. Starting 6.52 Ma, the abundance and diversity of planktonic foraminifera decreased. Continental inputs gradually dominate, alternating with marine ones, and reflecting a succession between proximal and distal neritic environments. The surface water conditions were warm. After 6.35 Ma, began the degradation of marine conditions. The continental environment shows an open vegetal landscape dominated by herbaceous plants, reflecting a tropical to arid subtropical climate, slightly less dry than that of the South Rifian Corridor. This study confirms the existence of several parameters that contributed to the deposition of the cyclical marl-diatomite series: on the one hand, the hot and dry climate favored the reduction of the plant landscape and therefore erosion (continental inputs); on the other, the tectonics (volcanism and uplift). Article carnetsgeol@rediris.es Wed, 17 Jan 2024 18:13:15 GMT https://doi.org/10.2110/carnets.2023.2309 Bruno Granier, Seyedeh Saeideh Mortazavi, Morteza Taherpour-Khalil-Abad & Farokh Ghaemi.- Chapter 1 - Preliminary investigations on the Zard Formation at its type locality (North Khorasan Province, Iran).- This chapter presents a revision of the Zard Formation in its type area, i.e., in the North Khorasan Province (Iran), including at its type locality. It comprises a description of the sedimentological and micropaleontological criteria that permit it to be distinguished from the Mozduran Formation (below) and the Tirgan Formation (above). At its type locality, its lower boundary is a heavily bored surface. Actually, both contacts with the framing formations correspond to transgressive surfaces, which imply that this lithostratigraphic unit is an Unconformity-Bounded Unit. With respect to biostratigraphy, this formation contains a few second-order markers: Holosporella sugdeni, Kopetdagaria sphaerica, and Torinosuella peneropliformis, which are also found in the unit above, i.e., in the Tirgan Formation. Because the latter contains markers that first appear in the Barremian: Bakalovaella elitzae, Pseudoactinoporella iranica, and Balkhania balkhanica, but also Montseciella arabica, the total range of which spans the Upper Barremian, the Zard Formation (i.e., the Zardian regional stage) should partly covers the Hauterivian to Barremian interval. Finally, although it cannot be definitely excluded that the lowermost part of the Zard Formation could be Valanginian in age, this option still requires proper documentation. Article carnetsgeol@rediris.es Sun, 10 Sep 2023 01:22:59 GMT https://doi.org/10.2110/carnets.2023.2308 Simon F. Mitchell.- A new pseudolepidinid foraminifer, Hanovolepidina browni gen. nov. sp. nov., from the middle Eocene (mid-Lutetian) of Jamaica and its significance.- The new larger benthic foraminifer, Hanovolepidina browni gen. nov. sp. nov., is described from the Chapelton Formation (mid-Lutetian, middle Eocene, ABZ7) of Jamaica. The genus shows the characteristic transition from a single to double equatorial layer about mid-way across the radius as seen in axial sections that characterises the family Pseudolepidinidae. Equatorial sections show the embryo followed by 4 or 5 spiral rotaliid chambers with the last chamber giving rise to a primary spiral and secondary (counter-) spiral of equatorial chambers. The presence of a long rotaliid stage suggests a more primitive form that Pseudolepidina, and Hanovolepidina gen. nov. differs also from the latter in lacking the extra principal accessory chamber seen in axial section. Hanovolepidina gen. nov. is provisionally suggested as an ancestor of the late Eocene Triplalepidina. The new discovery demonstrates a greater diversity of the family Pseudolpeidinidae in the Caribbean that previously recorded, although occurrences of this family are very restricted stratigraphically suggesting that it may appear in the region due to migration events. Article carnetsgeol@rediris.es Sun, 27 Aug 2023 01:19:09 GMT https://doi.org/10.2110/carnets.2023.2307 Bruno R.C. Granier, Serge Ferry & Mohamed Benzaggagh.- Hiatuses and redeposits in the Tithonian-Berriasian transition at Le Chouet (Les Près, La Drôme, SE France): Sedimentological and biostratigraphical implications.- Our new study of the Tithonian and lower Berriasian succession of Le Chouet (Les Près, La Drôme, France) better characterizes the lithological succession, the macro- and microfacies, and the stratigraphic ranges of some microfossils mostly calibrated on the calpionellid biozonation. On the lithological side, the Tithonian strata are dominantly characterized by thick-bedded breccias representing debris flows and related calciturbidites whereas the Berriasian strata are typically white limestones that also comprises scattered intercalations of thin-bedded breccias and calciturbitides (including cryptic mud calciturbidites). In thin sections, these white limestones display mud- to wackestone textures and their allochems are mostly tiny bioclasts (e.g., radiolarians, calpionellids, saccocomids). Breccias are lithoclastic rudstones and/or floatstones with a matrix similar to the calciturbidites. Their lithoclasts are either extraclasts sensu stricto (i.e., material derived from updip shallow-water areas) or pseudointraclasts, representing reworked subautochthonous material (i.e., mud- and wackestone lithoclasts with radiolarians, saccocomids and/or calpionellids). In addition to the erosional features observed at the bases of the gravity flows, these pseudointraclasts document the intensity of submarine erosion. Locally they help to estimate the depths of erosion updip of the deposit. A number of bioclasts are reworked from updip shallow-water areas; among them, it is worth mentioning the foraminifer Protopeneroplis ultragranulata (Gorbatchik), the first occurrence of which is dated to late early Tithonian. Saccocomids are part of the dominating pelagic biota reported from the lower and lower upper Tithonian interval whereas calpionellids replace them in the uppermost Tithonian to lower Berriasian interval. Intervals with saccocomids characteristic of zones 4-5 and zones 6-7 are respectively ascribed here to the lower Tithonian (4-5) and pro parte to the upper Tithonian (6-7). The biozonation of the calpionellid group sensu lato allows identification of the Boneti Subzone of the chitinoidellids, the Crassicollaria Zone with its four subzones (A0-A3), and the Alpina Zone with its first subzone (B1). On the basis of biostratigraphical and sedimentological data (including the rates of sedimentation), most zonal boundaries are located at the erosional bases of breccia or turbidite layers and thus coincide with hiatuses. Article carnetsgeol@rediris.es Tue, 27 Jun 2023 01:15:38 GMT https://doi.org/10.2110/carnets.2023.2306 Hamed Yarahmadzahi & Daniel Vachard.- Gzhelian (latest Carboniferous) Pseudoacutella partoazari foraminiferal assemblage from the Tabas Block (Central Iran).- A foraminiferal assemblage is reported from the Zaladou Formation in the Tabas Block (Shishtu Section), Central Iran. This assemblage comprises 16 species belonging to 14 genera, and encompasses the fusulinids Pseudoacutella partoazari, Grovesella tabasensis, Gr. aff. australis, Gr. sphaerica, Gr. sphaerica var. quadrata, Gr. cf. staffelloides, Schubertina sp., Schubertella sp., and the smaller foraminifers Eotuberitina sp., Lasiodiscus tenuis, Raphconilia cf. minor, R. multihelicis, R. modificata, Tetrataxis cf. parviconica, Globivalvulina ex gr. bulloides, Gl. graeca, Calcivertella heathi, Tansillites sp., Palaeonubecularia? sp., Hemigordiellina sp., Nodosinelloides longa, and N. longissima. The age of this assemblage is considered to be Gzhelian. The assemblage is dominated by the fusulinid Pseudoacutella partoazari with a low total diversity of smaller foraminifers. This assemblage is compared to similar assemblages in other parts of Iran and well as the USA. An evolutionary lineage of Pseudoacutella partoazari is also proposed. It is confirmed that Pseudonovella differs from Pseudoacutella by the periphery rounded-carinate (carinate in Pseudoacutella), pseudochomata less developed, and the type of coiling (Pseudoacutella is truly planispiral involute). Pseudonovella is suggested here as the ancestor of Pseudoacutella. This assemblage bears one unusual attribute, the overwhelming dominance of the fusulinid Pseudoacutella and the relatively low total diversity, compared with similar foraminifera from Alborz, Sanandaj-Sirjan, Sabzevar and central Iran, which present warm and humid conditions during the Late Carboniferous. Article carnetsgeol@rediris.es Fri, 30 Jun 2023 01:12:44 GMT https://doi.org/10.2110/carnets.2023.2305 Olev Vinn & İzzet Hoşgör.- The first record of Middle Jurassic serpulids from SE Turkey, equatorial Tethys.- The Jurassic platform margin succession in the Hezan area, called the "Hezan Unit" (Diyarbakır), on the north of the Arabian platform in southeastern Turkey includes five formations of carbonate-dominated rocks. The most interesting is the upper part of the Hezan unit (the Kuran Formation) that contains unique layers of oolitic and clayey limestone. A first record of the calcareous polychaete tubeworm Propomatoceros lumbricalis is described from the Middle Jurassic lower part of the Kuran Formation of the Hezan area. Most knowledge of fossil serpulids is centered on European material, and little has been done on Middle East fossil calcareous tubes. The taxonomic information recorded as a result of this study will add to our understanding of the biogeographic history of the Middle Jurassic calcareous polychaete associations and help to interpret the structure and paleoecology of its marine communities. Article carnetsgeol@rediris.es Fri, 30 Jun 2023 01:10:55 GMT