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Clumped isotopes thermometry (Δ47) and U-Pb dating of carbonates have been used to elucidate the temperature-time conditions of 10 tectonic calcite veins in the hanging wall of the South Pyrenean Frontal Thrust (Spain), the youngest thrust unit in the south-central Pyrenees. The Δ47 values indicate precipitation temperatures below ∼90 °C, in agreement with fluid inclusion analyses. 6 veins have been successfully dated, giving ages between 61 and 14.5 Ma with all but one value below 24 Ma. On the basis of our new results, we propose that several the studied veins record the end of Pyrenean tectonics in the area during the Burdigalian, possibly up to the Serravalian, younger than estimates based on magnetostratigraphic data from continental syn-tectonic deposits. Calculated δ18O values of the precipitating fluid are either very positive, suggesting a local source that has interacted with the host rock, or negative, suggesting the downward incursion of meteoric waters. For undated or pre-burial veins, the Δ47 values derived from temperature history reordering model (THRM) show that the measured Δ47 values may have been significantly altered during burial, preventing their use as a reliable thermal or paleohydrological marker. Although applied to a limited number of samples, these results highlight the great potential of the U-Pb/Δ47 approach to decipher the history of vein or cement formation and fluid flow in complex tectonic zones, provided that (i) the thermal evolution is known and (ii) the extent of clumped isotope reordering is systematically modelled., This work benefited from a PhD grant of the French Ministry of Research (MESR) to NC. All analyses and field work performed in the course of this study were funded by a “CNRS excellence chair” grant to GH.

ACL; International audience; This study aims at understanding the origin and nature of syn-orogenic fluid flow in the Jaca basin from the South Pyrenean fold and thrust-belt, as recorded in calcite and quartz veins of the Sierras Interiores (Spain) and the turbiditic basin, which cover upper Cretaceous to Late Eocene syntectonic deposits. The fracture network consists of a classical pattern of transverse and longitudinal fractures related to Layer Parallel Shortening (LPS) and folding respectively. Veins filled equally about the third of fractures in the carbonate shelf and turbidites. Carbon and oxygen isotopes of calcite veins mostly indicate precipitation from isotopically buffered water, consistent with high water-rock interaction. In the Sierras Interiores, petrographical observations and fluid inclusion microthermometry are consistent with two distinct stages of precipitation. The first stage is characterized by relatively low Th and low salinities (155-205 °C and 0.5-3.2 wt% eq. NaCl). The second stage, which was characterized both by the formation of mode-I joints and by mode-I reactivation of pre-existing veins, shows higher Th and salinities (215-270 °C and 2.2-5.7 wt% eq. NaCl). Waters recorded in the second stage are interpreted to have interacted with underlying Triassic evaporites and flowed along major thrusts before vein precipitation, which are locally in thermal disequilibrium with host-rocks. We suggest the transition from a rather closed hydrological system during the first stage of vein formation, interpreted to have occurred during Eaux-chaudes thrusting (upper Lutetian-Bartonian), to a more open hydrological system during the second stage, which likely occurred during Gavarnie thrusting (Priabonian-early Rupelian). Finally, we also document the migration in space and time of hydrothermal pulses along the South Pyrenean Foreland Basin, related to the westward propagation of major thrusts during the Pyrenean orogeny. © 2017 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists.

International audience; Among some modern and recent fossil species of planktonic foraminifera, the proportion of left-to right-coiled shells in a population appears to be temperature-dependent; the relative abundance of each morphotype reflecting ecological preferences. A similar relationship is identified among Muricohedbergella delrioensis (Carsey, 1926) at the Cenomanian-Turonian stage boundary in mid-latitude sites of the Western Interior Seaway, including the Pueblo type section. The increase of sinistral M. delrioensis in the assemblage is related to higher  18 O carb values and decrease in inner porosity which suggests that changes in the coiling direction in this morphospecies could represent a new proxy for constraining Sea Surface Temperature (SST) variations. As surface dwellers, muricohedbergellids were not ACCEPTED MANUSCRIPT 2 affected by Oceanic Anoxic Event (OAE2) and provide a continuous paleoclimatic signal throughout the Cenomanian-Turonian boundary interval. Furthermore, genetic evidence obtained from extant foraminifera indicates that shifts of coiling ratios in planktonic foraminifera species can express the signature of distinct genetic types, which are revealed through their opposite coiling directions. Coiling direction could be a genetic trait, implying that cryptic species may occur in the Mesozoic.