BUSCADOR RECOLECTA

Thick gypsum-carbonate sequences were deposited in different periods and basins of Europe during the westward opening of the Tethys Ocean. Although they seem to represent widespread perimarine sulphate-dominated lagoons in shallow epeiric platforms, the sedimentary characteristics and interpretation of these deposits are still poorly constrained. To advance in the knowledge of these deposits, a detailed study is presented of two distinctive sulphate dominated sequences of Late Triassic age located in NE Iberia (Western Europe), which correspond to the Canelles and Espinagosa units, found in the southern Pyrenees and the Catalan Coastal Ranges respectively. These sequences present a diverse suite of carbonate and sulphate lithofacies, which are stacked in several recurring sedimentary cycles. These cycles consistently present a carbonate base that transitions to a sulphate top, and can be correlated along several tens of kilometres. Each of the observed cycles depicts an initial sudden flooding of a tidal-lagoon system by marine water, which led to carbonate-dominated sedimentation. Progressive evaporation under dominant arid climate conditions triggered the shallowing of the lagoon and salinisation of its water. Then, a transition from carbonate to gypsum/anhydrite precipitation and the early dolomitisation of the underlying carbonate sediments by brine reflux occurred. Gypsum precipitated in the water column as cumulate crystals and deposited at the bottom of the lagoon, forming laminations or being incorporated into microbial mats. Anhydrite precipitated as early diagenetic crystals in the different subaqueous and subaerial environments of the tidal-lagoon system, leading to a variated set of lithofacies until now largely undocumented. It mainly formed as displacive lath-shaped crystals randomly oriented within carbonate muds at the bottom of the lagoon, which were mostly reworked at the lagoon margins by wave and tidal currents resulting in aligned fabrics in cross-lamination structures. Anhydrite also formed as pure massive beds by anhydritisation of subaerially exposed gypsum sediments during the main retraction stages of the lagoon, as well as typical nodular (sabkha) lithofacies. Such sulphate lithofacies are not easy recognisable due to the lack of modern analogues to compare and to their current transformation into secondary gypsum in the outcrops. These are aspects to be taken into account in future sedimentological studies on similar evaporitic materials., Peer Reviewed

The Campo Coy Basin (SE Spain) exposes >1 km of sedimentary succession with a variety of rocks including a thick evaporitic succession previously associated with the Messinian time. These evaporites were supposedly deposited in a restricted Mediterranean-Atlantic seaway connecting the Lorca and Guadix-Baza basins, although no chronological or geochemical data existed. Here we use palaeomagnetism together with vertebrate and foraminifera biostratigraphy to constrain the age of the Campo Coy succession between <9 Ma and 4.7 Ma. We use geochemistry (δ34S, δ18O and 87Sr/86Sr values) of the gypsum deposits to evaluate their marine or continental origin. In addition, we describe the underlying and overlying lithostratigraphic units to reconstruct the palaeogeographic evolution of this region. Our results show that the sediments were deposited in a continental environment, indicating that the Betic Seaway was already closed in this region during the late Tortonian and that the neighbouring marine basins of Guadix-Baza and Lorca were disconnected during that time. The δ34S, δ18O and 87Sr/86Sr values of the gypsum indicate recycling from the Triassic sulphates. Sedimentary facies of the evaporites point to an environment dominated by a saline lake with continental sabkha episodes developed during the driest periods. Well-defined and laterally continuous evaporitic cyclicity suggests an orbital forcing and high sedimentation rates preceding the Messinian Salinity Crisis (MSC). Alluvial deposits are contemporaneous with the MSC indicating a dry continental environment in this region during the Mediterranean restriction. Overlaying lacustrine carbonates are rich in small vertebrate fauna including African species that migrated to Europe during the MSC. These carbonates have low δ18O and δ13C values characteristic for freshwater input in an open lake just after the Zanclean flood, suggesting that a wet climate followed the MSC., Funding was provided by the grants CGL-2016-79458 and PID2020-118999GB-I00 from the Spanish Ministry of Science and Innovation (MCIN)/ State Research agency of Spain (AEI)/10.13039/501100011033, and by the Catalonian Government Actions 21-SGR-829 and PGC2018-094122-B-100.

The Messinian Salinity Crisis is considered as one of the most influential Cenozoic events that impacted negatively on the benthic fauna of the Mediterranean area. Changing environmental conditions, including a sharp reduction of water exchange between the Mediterranean Sea and the Atlantic Ocean, altered the geographical ranges of many organisms, including sponges (Porifera). Here, we report a unique assemblage of isolated sponge spicules from the upper Miocene of southwestern Spain. The newly recognized sponge fauna was inhabiting the Guadalquivir Basin—the corridor between the Mediterranean and the Atlantic Ocean at that time. It represents a taxonomically rich sponge community that consisted of members of “soft” and “lithistid” demosponges and hexactinellids. Demosponges are represented by at least thirty-four taxa, while hexactinellids are significantly rarer; only six taxa have been identified. From among eighteen taxa recognized to the species level, at least eight seem to be inhabiting this area to these days; six are recorded from adjacent areas, such as the Western Mediterranean, South European Atlantic Shelf, and the Azores, and three are present in the Red Sea and/or the Northern Atlantic. Intriguingly, some taxa seem to have their closest relatives in distant areas, such as the Indo-Pacific and Japanese waters which suggests that the range of some once widely-distributed populations shrunk after the isolation of the Mediterranean and the Messinian Salinity Crisis, surviving to the present day only in refugia., This work was supported by EVAMED (PID2020-118999GB-I00) funded by the Spanish Ministry of Science and Innovation/State Research Agency of Spain (AEI).

The assessment of the deep geothermal potential is an essential task during the early phases of any geothermal project. The well-known "Heat-In-Place" volumetric method is the most widely used technique to estimate the available stored heat and the recoverable heat fraction of deep geothermal reservoirs at the regional scale. Different commercial and open-source software packages have been used to date to estimate these parameters. However, these tools are either not freely available, can only consider the entire reservoir volume or a specific part as a single-voxel model, or are restricted to certain geographical areas. The 3DHIP-Calculator tool presented in this contribution is an open-source software designed for the assessment of the deep geothermal potential at the regional scale using the volumetric method based on a stochastic approach. The tool estimates the Heat-In-Place and recoverable thermal energy using 3D geological and 3D thermal voxel models as input data. The 3DHIP-Calculator includes an easy-to-use graphical user interface (GUI) for visualizing and exporting the results to files for further postprocessing, including GIS-based map generation. The use and functionalities of the 3DHIP-Calculator are demonstrated through a case study of the Reus-Valls sedimentary basin (NE, Spain).

Karst fills from the onshore Penedès Basin and offshore València Trough display red, pink, orange and ochre colours. Their Mössbauer spectra indicate that Fe contained in goethite is the dominant species in reddish-pink fills, whereas Fe contained in dolomite and clays is more dominant in the orange and ochre ones. The lower δ C values and higher Sr/ Sr ratios of the karst fills with respect to their host carbonates can reflect the input of soil-derived CO and an external radiogenic source into the karst system. This geochemical composition, together with the non-carbonate fraction of the fills, consists of authigenic and transported illite, illite-smectite interlayers, as well as kaolinite, chlorite, pyrite, quartz, ilmenite, magnetite, apatite and feldspar, account for a mixed residual-detrital origin of fills. This polygenic origin agrees with that of the terra rossa sediments described worldwide. The different colours of karst fills are attributed to fluctuations in the water table, which control the Eh/pH conditions in the karst system. Thus, reddish colours reflect low water table levels and oxidising episodes, and orange and ochre ones reflect high water table levels and more reducing episodes. The greenish colours of fills could be related to fluctuations in the Fe /Fe ratio.

Karst fills from the onshore Penedès Basin and offshore València Trough display red, pink, orange and ochre colours. Their Mössbauer spectra indicate that Fe3+ contained in goethite is the dominant species in reddish-pink fills, whereas Fe2+ contained in dolomite and clays is more dominant in the orange and ochre ones. The lower δ13C values and higher 87Sr/86Sr ratios of the karst fills with respect to their host carbonates can reflect the input of soil-derived CO2 and an external radiogenic source into the karst system. This geochemical composition, together with the non-carbonate fraction of the fills, consists of authigenic and transported illite, illite-smectite interlayers, as well as kaolinite, chlorite, pyrite, quartz, ilmenite, magnetite, apatite and feldspar, account for a mixed residual-detrital origin of fills. This polygenic origin agrees with that of the terra rossa sediments described worldwide. The different colours of karst fills are attributed to fluctuations in the water table, which control the Eh/pH conditions in the karst system. Thus, reddish colours reflect low water table levels and oxidising episodes, and orange and ochre ones reflect high water table levels and more reducing episodes. The greenish colours of fills could be related to fluctuations in the Fe3+/Fe2+ ratio, This research was performed within the framework of DGICYT Spanish Projects PGC2018-093903-B-C22 and PID2020-118999GB-I00 funded by the Ministerio de Ciencia, Innovación y Universidades/Agencia Estatal de Investigación/Fondo Europeo de Desarrollo Regional. EGR acknowledges the funding provided by the Spanish Ministry of Science, Innovation and Universities (“Ramón y Cajal” fellowship RYC2018-026335-I). The isotopic, electron microprobe and XRD analyses and the SEM and TEM observations were carried out at “Centres Científics i Tecnològics” of the Universitat de Barcelona. Mössbauer spectroscopy analyses were carried out at Institut de Ciència de Materials de Barcelona. Strontium isotope analyses were carried out at “CAI de Geocronología y Geoquímica Isotópica” of the Universidad Complutense de Madrid., Peer reviewed

DATA & FILE OVERVIEW

1. File List:

00_IESDB_Readme
IESDB_Dataset1_Generic-Data
IESDB_Dataset2_Mining-Data
IESDB_Dataset3_Well-and-Seismic-Data
IESDB_Dataset4_Geographic-Data
IESDB_Dataset5_Quantitative-Data
IESDB_Dataset6_Reference-Data
IESDB_Dataset7_Image-Data
IESDB_Summarized-Index-Cards, The Iberian Evaporite Structure Database (IESDB) is the first overall assessment of evaporite structures developed in any region of the world. The IESDB is sourced from six different databases and more than 1,500 published and unpublished references, and includes information and figures for each of the 150 inventoried evaporite structures and their surrounding rocks. The database targets outcropping and buried diapirs, undeformed to slightly deformed evaporite successions, evaporite-cored anticlines, evaporite-detached thrusts, and allochthonous evaporite bodies. Compiled data include information about the stratigraphy, structure, event chronology, subsurface data availability, mining activity, and key bibliographic references of each indexed structure. The IESDB follows the FAIR principles of database management (Findable, Accessible, Interoperable and Reusable) and is presented as an open access webpage (https://iesdb.eu/)., This research initiative is funded by the Ramón y Cajal Fellowship RyC-2018-026335-I and Juan de la Cierva-Incorporación Fellowship IJC2018-036074-I (Spanish Ministry of Science and Innovation (MCIN) / State Research Agency of Spain (AEI) / 10.13039/501100011033) / European Regional Development Fund
(ERDF), the Knowledge Generation Research Project PID2020-118999GB-I00 (Spanish Ministry of Science and Innovation (MCIN) / State Research Agency of Spain
(AEI) / 10.13039/501100011033) and the Consolidated Research Group “Geologia Sedimentària” (2017SGR-824)., 00_IESDB_Readme IESDB_Dataset1_Generic-Data IESDB_Dataset2_Mining-Data IESDB_Dataset3_Well-and-Seismic-Data IESDB_Dataset4_Geographic-Data IESDB_Dataset5_Quantitative-Data IESDB_Dataset6_Reference-Data IESDB_Dataset7_Image-Data IESDB_Summarized-Index-Cards, Peer reviewed

As one of the predominant diagenetic products in clastic rocks, calcite cements are typical fingerprints of cement-forming fluids and are key controls on reservoir quality. The Puig-reig anticline, in the south-eastern Pyrenees (Spain), exposes excellent outcrops of conglomerates, sandstones and claystones, which were deposited from a proximal to medial fluvial system and underwent folding, fracturing and cementation. This anticline constitutes an appropriate case study to investigate the origin and distribution of calcite cements during folding evolution and how they affect reservoir quality. Based on structural, petrographic and geochemical analyses (carbon, oxygen, strontium and clumped isotopes and elemental composition), five generations of calcite cements (Cc0 to Cc4) have been identified, filling intergranular porosity of host rocks, faults and four fracture sets (F1 to F4). Calcite cement Cc0 precipitated in intergranular porosity from meteoric fluids in the phreatic zone during the early diagenetic stage. During the most intense phase of thrusting and folding, Cc1 precipitated in intergranular porosity, faults and F1 to F4 fracture sets from hydrothermal fluids that migrated from deeper areas of the Pyrenean chain. During the late stage of fold growth, Cc2 precipitated in faults and their associated fractures in the anticline crest from hydrothermal fluids but at shallower burial depths than that of Cc1. Calcite cement Cc3 mainly precipitated in fractures with the same strike as F1 and F4 fracture sets in the north-western part of the anticline, from formation fluids that probably migrated through the frontal thrust of the south-eastern Pyrenees. During the continuous fold denudation, Cc4 precipitated from meteoric fluids in F1 to F4 fracture sets across the anticline. Results indicate that at foreland basin margins, external fluids coeval with compressional deformation and/or alteration of detrital carbonates contribute to intensive calcite cementation. This can result in an overall occlusion of porosity and significantly damaged reservoir quality., was provided by the Catalan Council to the Grup Consolidat de Recerca “Geologia Sedimentària”
(2017SGR-824) and research projects PGC2018-093903-B-C22 and PID2020-118999GB-I00, funded by
the Spanish Ministry of Science and Innovation (MCIN) / State Research Agency of Spain (AEI)
/10.13039/501100011033. XS acknowledges funding by the China Scholarship Council for a PhD
scholarship (201806450043). EGR acknowledges the Ramón y Cajal fellowship RYC2018-026335-I and
JA the Juan de la Cierva-Incorporación fellowship IJC2018-036074-I, both funded by the Spanish Ministry
of Science and Innovation (MCIN) / State Research Agency of Spain (AEI) / European Regional
Development Fund (ERDF) /10.13039/501100011033., Peer reviewed

There is ongoing debate on whether stylolites act as barriers, conduits, or play no role in fluid transport. This problem can be tackled by examining the spatial and temporal relationships between stylolites and other diagenetic products at multiple scales. Using the well-known Lower Cretaceous Benicàssim case study area (Maestrat Basin, E. Spain), we provide new field and petrographic observations of how bedding-parallel stylolites can influence different diagenetic processes during basin evolution. The results reveal that stylolites can serve as baffles or inhibitors for different carbonate diagenetic reactions, and act as fronts for dolomitization, dolomite recrystallization and dolomite calcitization processes. Anastomosing stylolites that pre-date burial dolomitization probably acted as a collective baffle for dolomitization fluids in the study area, resulting in stratabound replacement geometries at the metre-to-kilometre scale. The dolomitization front coincides with stylolites, and can be traced along consecutive anastomosing ones. Such anastomosing stylolites are typical of mud-dominated facies that characterize limestone-dolostone transition zones. Conversely, dolostone bodies tend to correspond to more grain-dominated facies characterized by parallel (non-anastomosing) stylolites. Stylolites subsequently acted as fluid flow conduits and barriers when the burial and stress conditions changed. Stylolitic porosity enhanced by dissolution within dolostones close to faults appears filled with saddle dolomite riming the stylolite pore, and high-temperature blocky calcite cements filling the remaining porosity. The fluids responsible for these reactions were likely released from below at high pressure, causing hydraulic brecciation, and were channelised through stylolites, which acted as fluid conduits. Stylolites are also found acting as baffles for subsequent dolomite calcitization reactions during meteoric diagenesis and occasionally appear filled with iron oxides likely released by calcitization. This example demonstrates how the same type of stylolites (bedding-parallel) can act as barriers/inhibitors and/or conduits for different types of diagenetic reactions through time, and how important it is to consider their collective role when they form networks., This research was carried out within the framework of the Spanish Ministry of Science and Innovation Projects PGC2018-093903-B-C22 and PID2020-118999GB-I00, the Grup Consolidat de Recerca “Geologia Sedimentària” (2017-SGR- 824, funded by the Agency for Management of University and Research Grants, Catalan government, Spain) and the DGMK (German Society for Petroleum and Coal Science and Technology) project 718, funded by the companies ExxonMobil Production Deutschland GmbH, GDF SUEZ E&P Deutschland GmbH, RWE Dea AG, and Wintershall Holding GmbH. EGR acknowledges funding by the Spanish Ministry of Science, Innovation and Universities (“Ramón y Cajal” fellowship RYC2018-026335-I), and the Geological Society of London Elspeth Matthews Fund 2015 grant. MGL acknowledges funding by the Spanish Ministry of Science, Innovation and Universities (“Juan de la Cierva-Incorporación” fellowship IJC2018-036826-I)., Peer reviewed

Renewable energy sources are key to achieve the transition toward clean energy system. Among them, the geothermal energy has a production whose effectiveness requires sufficient understanding of the temperature distribution and fluid circulation at depth, as well as of the lithological and petrophysical properties of the crust. The focus of this paper is twofold: first, we summarize the main advances in the development of new methodologies and numerical codes to characterize the properties of the thermal lithosphere in terms of its, temperature, density and composition; second, based on the compilation of available thermal modelling results, we present the depth of the thermal Lithosphere–Asthenosphere Boundary (LAB) of the Iberian Peninsula and the temperature distribution at crustal depths of 5, 10, and 20 km, in addition to at Moho level. At 5 km depth, the temperature is above 110 °C with local anomalies (> 130 °C) located in the Iberian Massif and Cenozoic volcanic provinces. A similar pattern is observed at 10 and 20 km depth, where temperatures are above 190 °C and 350 °C, respectively. At 20 km depth, anomalies above > 500 °C, delineate the SE and NE Cenozoic volcanic provinces. At Moho depths, temperature ranges from 450 to 800 °C with hot regions mainly located along the Iberian Massif and the SE and NE volcanic provinces. The compiled results do not show any lithospheric anomaly that could give rise to high temperatures at shallow depths, but they do show an acceptable exploitation potential at intermediate depths. With regard to the direct use of district and greenhouse heating and for industrial processes, the potential is great throughout the Peninsula, the main challenges being the availability of groundwater and drilling costs., This work has been supported by EVAMED (PID2020-118999GB-I00) and GEOCAM (PGC2018-095154-B-100) funded by the Spanish Ministry of Science and Innovation/State Research Agency of Spain (AEI)/https://doi.org/10.13039/501100011033.e). JA is funded by Grant IJC2018-036074-I and EGR by the Ramón y Cajal Fellowship RYC2018-026335-I, both funded by the Spanish Ministry of Science and Innovation (MCIN)/State Research Agency of Spain (AEI). Additional funding comes from the European Regional Development Fund (ERDF)/https://doi.org/10.13039/501100011033.e., Peer reviewed

Fluvial system deposits often form suitable reservoirs for CO geological storage (CGS). These potential storage sites usually present heterogeneous fluvial architectures at multiple scales. This heterogeneity can exert varied effects on different aspects of CGS, resulting in significant storage efficiency variability. Here, we investigate the effects of variable fluvial lithofacies associations on CO storage, using the Puig-reig anticline in the SE Pyrenees (Spain) as a reservoir analog. To test this, we employ a multidisciplinary approach that integrates field sedimentology, reservoir modeling, and numerical simulation of CO injection to produce models akin to different fluvial lithofacies associations. The storage volume and injectivity of CO are found to decrease in reservoirs with decreasing fractions and sizes of high-permeable facies from the proximal to the medial-distal lithofacies associations. The flow barriers created by low-permeable facies can hinder the vertical migration of the CO plume and prevent it from reaching the reservoir top, hence reducing the direct contact between the CO plume and the overlying caprock. Furthermore, an optimal amount of low-permeable layers (around 30% in this study) can increase the swept area of CO and reduce the proportions of free CO phase. These aspects can collectively increase the amount of permanently trapped CO and reduce the leakage risks of the injected CO. Based on the characteristics of the resulting models (i.e., storage volume, injectivity, distribution and phases of CO), a multi-criteria decision-making method has been used to quantitatively rank the different lithofacies associations according to their suitability for CO storage. In this analysis, the proximal-medial fluvial lithofacies associations are assessed to be the most suitable ones because they feature low proportions of the injected CO reaching the reservoir top and in free phase while maintaining the high storage volume and injectivity. This study reveals that heterogeneous reservoir architectures have mixed effects on CO storage, and that reservoirs featuring moderately heterogeneous architectures (i.e., fractions of low-permeable facies ranging from 30% to 40%) are beneficial to keeping the balance among different aspects of CO storage. This provides new insights for the screening and selection of potential geological sites for CO storage., Funding was provided by the China University of Petroleum (East China) to the Independent Innovation Research Project 22CX06004A and by the Catalan Council to the Grup Consolidat de Recerca “Geologia Sedimentària” (2017SGR-824) and the DGICYT Spanish Projects PGC2018-093903-B-C22, PID2020-118999GB-I00 and PID2021-122467NB-C22 (MCIN/AEI/10.13039/501100011033/FEDER, Unión Europea). JA acknowledges funding from MICINN (Juan de la Cierva fellowship - IJC2018-036074-I)., Peer reviewed

Evaporite rocks are one of the most mined mineral commodities and act as a seals or shaping traps in some of the major hydrocarbon provinces worldwide. In addition, they are also considered as suitable sites for the storage of energy and nuclear waste, being a key asset for the energy transition. Due their historic, present and future value, vast amounts of surface and subsurface information about evaporite structures have been generated by earth scientists, mining and exploration companies or geological surveys in the last century. However, this information is often scarcely useful due to access issues, segregation and scarce dissemination. Here we present the Iberian Evaporite Structure DataBase (IESDB), the first overall assessment focused on evaporite structures developed in any region of the world. The IESDB includes information and figures of 150 outcropping and buried evaporite structures and their surrounding rocks inventoried in Iberia. The Iberian Evaporite Structure Database (IESDB) includes information about the stratigraphy, structure, evolution, geophysical and petrophysical data availability, and mining activity, including a complete set of geological maps, sketches and geological cross-sections. The database targets different evaporite structures, such as undeformed successions, diapirs, evaporite-cored anticlines, evaporite-detached thrusts or allochtonous evaporite bodies. The IESDB is sourced from six different databases and more than 1,500 published and unpublished references, and includes information and figures for each of the 150 evaporite structures inventoried. The IESDB follows the FAIR principles of data management (Findable, Accessible, Interoperable, Reusable) and aims to be a resource for earth science teaching, academic research and resource exploration and appraisal. The IESDB is freely available at https://iesdb.eu, This research was performed within the framework of DGICYT Spanish Project PID2020-118999GB-I00 funded by the Ministerio de Ciencia, Innovación y Universidades/Agencia Estatal de Investigación/Fondo Europeo de Desarrollo Regional. Grants RYC2021-033872-I (Juan Alcalde) and RyC-2018-026335-I (Enrique Gomez-Rivas) funded by MCIN/AEI/10.13039/501100011033 and ESF ¿Investing in your future¿.

In this study a modus operandi to investigate site-specific nanostructures in thin films (lamellae) excavated “in-plane” across (sub)grain boundaries is presented. This is done by discussing the case of a magnetite grain hosted in a thin section of banded iron formation (Norway) that is prepared parallel to the kinematic reference frame (XZ section of the strain ellipsoid). SEM-EBSD analysis reveal that the magnetite grains do not develop a strong crystallographic preferred orientation, although individual grains are strained and show evidence of intracrystalline deformation in form of low angle grain boundaries (LAGB's). Two “in-plane” lamellae using focused ion beam (FIB) technique are excavated from a magnetite grain in the kinematic reference frame, and nanostructures are studied along three LAGB's using high resolution transmission electron microscopy imaging followed by Fourier transformation (FT), inverse FT and estimation of dislocation densities. Our data establish an empirical relationship for the studied LAGBs, namely, the smaller the angle between LAGB and X-direction, the larger are the shear strain and dislocation density. This relationship is validated from numerical simulations of viscoplastic deformation and dynamic recrystallisation of polycrystalline aggregates of halite, which is also a cubic mineral analogous to magnetite. In addition to the site-specific “in-plane” FIB lamella information, this study also shows that in a deformed mineral the different orientations of the LAGB compared to the principal strain axes show a different dislocation density. This approach of full tracking of the extension direction (X) from the macroscopic to the nano-scale could play an important role in forward modelling of microstructure evolution in future studies., This study is an outcome of a collaborative research project funded by the Alexander von Humboldt Foundation (Germany) under its Research Group Linkage Program awarded to MAM, AK and CH. Amarnath Dandapat (Department of Geology and Geophysics, IIT Kharagpur, India) is thanked for preparing well-polished samples for EBSD analysis. Thanks to B. Priesemann (Helgeland Museum, Norway) for kindly providing the magnetite ore sample. Thanks are due to Niloy Bhowmik for helping with SEM-EBSD analysis at the Central Research Facility (IIT Kharagpur, India). We are grateful to Heike Störmer for helping with TEM analysis at the Laboratory for Electron Microscopy, Karlsruhe Institute of Technology (Karlsruhe, Germany). EGR acknowledges the Ramón y Cajal fellowship ( RYC 2018-026335-I ), funded by the Spanish Ministry of Science and Innovation (MCIN)/State Research Agency of Spain (AEI)/European Social Fund ( 10.13039/501100011033 ), and the research project PID 2020-118999 GB-I00, also funded by the MCIN/AEI/10.13039/501100011033.

This study combines published isotope data (223 samples) with new data (153 samples) on the δS and δO composition of Ca-sulfate rocks (anhydrite and secondary gypsum) accumulated in eastern Iberia during the Middle Triassic to Early Jurassic. The δS mean values of the evaporite units reveal the following trends: a decrease from the lower Anisian (~18‰) to the Carnian-Norian interval (~15‰); an increase at the Rhaetian (~16‰); a decrease in the Hettangian-Sinemurian interval (~14‰); and finally an increasing trend from the Sinemurian-Pliensbachian (~16‰) to the Pliensbachian-Toarcian (~19‰). This δS isotope assemblage together with the generalized low standard deviations observed for the different evaporite units is consistent, and suggests that the isotope composition of these Ca-sulfates are primary signatures related to feeding marine water sulfate. Depending on the evaporite units, these δS mean values are, nevertheless, ~1‰ to ~3‰ lower than those reported for coeval Triassic evaporites of the Germanic basin and the Alp-Apennine domains. In eastern Iberia, the δO values are more variable and also display wider scatters than the corresponding δS values. Of particular interest in our study are: (i) the low δS values for the Anisian in comparison with those in the Germanic basin; (ii) the shift to heavier values in the Rhaetian, recorded for first time in the evaporites of eastern Iberia; (iii) the low values observed for the Hettangian, which suggest that the change to the heavier values of the Jurassic (~19‰) occurred after the end-Hettangian in eastern Iberia; and (iv) the affinity of the δS values recorded for the Hettangian-Sinemurian interval to those known for the Canadian domain., This study was supported by the following research projects: 2017SGR-824 (SEDIMENTARY GEOLOGY), Departament d'Innovació, Universitats i Empreses of the Catalan Government; CGL2016-79458-P (Ministerio de Economía y Competitividad), PGC2018-098272-B-I00, PID2019-104625RB-I00 and PID2020-118999GB-I00 (Secretaría Estado I+D+I; Ministerio de Ciencia e Innovación) of the Spanish Government; and B-RNM-072-UGR18 (FEDER Andalucía), P18-RT-4074, and RNM-208 (Junta de Andalucía).