Carbon and Nitrogen Cycle Dynamic in Continental Late-Carboniferous to Early Permian Basins of Eastern Pangea (Northeastern Massif Central, France)

Late Carboniferous to early Permian organic-rich sedimentary successions of late-orogenic continental basins from the northeastern Massif Central (France) coincide with both Variscan mountain dismantling and acme long-lasting Paleozoic Ice Age. Here, we investigate carbon nitrogen cycles in newly dated Decize–La Machine Autun during these geodynamic climate upheavals. The organic matter has been analyzed through Rock-Eval pyrolysis, palynofacies elemental isotope geochemistry along cored-wells outcropping sections, previously accurately defined terms paleo-depositional environments. data have evidenced two origins matter: a phytoplanktonic/bacterial lacustrine origin (Type I matter, ? 13 C values around ?23.5‰), terrestrial (vascular land plants, Type III ?20‰), mixed deltaic-lacustrine sediments background sedimentation (mean ?22‰). Episodes high storage, reflected by black shales coal-bearing deposits (total up 20 70%, respectively) are also recognized successions, characterized large negative excursions down ?29‰. We suggest that reflect secondary processes, such as remineralization and/or productivity varying under strict local controls, or possibly larger scale controls. At times, paired positive 15 N +10‰, reflecting water column denitrification anammox lake-water stratification episodes. Together, isotopic signals (i.e., low associated bulk values) indicate periods primary surface waters, where spatially decoupled. These processes on archives may partially blur our ability directly reconstruct paleoclimate variations settings using only isotopes. last, explore an C-based mixing model propose ways disentangle autochthonous versus allochthonous settings.