FN Archimer Export Format PT J TI The organic, inorganic and isotope geochemistry of the Holocene sapropel units in the Sea of Marmara and their Paleoceanographic significance BT AF Liu, Yingjia Lu, Xindi Çağatay, M.Namık Zhang, Yixuan Li, Yuanyuan Peng, Yongbo Ruffine, Livio Lu, Hailong AS 1:1,2;2:2,3;3:4;4:2,3;5:1,2;6:5;7:6;8:2,3; FF 1:;2:;3:;4:;5:;6:;7:PDG-REM-GM-LCG;8:; C1 College of Engineering, Peking University, Beijing 100871, China Beijing International Center for Gas Hydrate, Peking University, Beijing 100871, China School of Earth and Space Sciences, Peking University, Beijing 100871, China EMCOL Research Centre, Istanbul Technical University, Istanbul, Turkey Department of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803, USA Ifremer, Département Ressources physiques et Ecosystèmes de fond de Mer (REM), Unité des Géosciences Marines, Laboratoire des Cycles Géochimiques et ressources (LCG), 29280 Plouzané, France C2 UNIV PEKING, CHINA UNIV PEKING, CHINA UNIV PEKING, CHINA UNIV TECH ISTANBUL, TURKEY UNIV LOUISIANA STATE, USA IFREMER, FRANCE SI BREST SE PDG-REM-GM-LCG IN WOS Ifremer UPR copubli-int-hors-europe copubli-sud IF 5.361 TC 2 UR https://archimer.ifremer.fr/doc/00690/80241/83316.pdf LA English DT Article CR MARSITECRUISE BO Pourquoi pas ? DE ;Sea of marmara;Holocene sapropel;Ocean redox structure;Nitrogen utilization;Organic matter sources AB The ocean redox structure and nitrogen utilization are investigated in the Holocene sapropel depositions in the Sea of Marmara, based on inorganic, organic, and isotopic analyses and grain-size distribution of the sediments of a piston core from Çınarcık Basin. Two sapropel units are identified in the core studied, the lower (main) sapropel of the early Holocene and the upper sapropel of the middle-late Holocene. Relatively high C/N ratios (10-11) and smaller δ13Corg values (∼ -26‰) in the lower Holocene sapropel unit indicate that the organic matter is mainly of terrestrial origin. Up to 5.5‰ δ15N values and Mo concentration (6.5 ppm) above crustal values in the bottom of the lower sapropel unit strongly suggest that bottom-water conditions were denitrifying and suboxic-dysoxic, suitable for the preservation and burial of the organic matter. Such bottom-water conditions were induced by water stratification that resulted from the transgression from the Aegean Sea coupled with a riverine influx from the Black Sea that provided the terrestrial organic matter. A progressive upward decrease of C/N ratios and increase of δ13Corg values in the upper sapropel unit might have been caused by the additional supply of organic matter of mainly marine origin and improved ventilation of the lower water, which resulted in the oxidation of the organic nitrogen pool and a decrease of δ15N values (below 3‰) under nitrate-rich conditions. Mn enrichment in the upper sapropelic sediments also supports a relatively oxidative environment. PY 2021 PD JUN SO Marine And Petroleum Geology SN 0264-8172 PU Elsevier BV VL 129 UT 000657399900004 DI 10.1016/j.marpetgeo.2021.105094 ID 80241 ER EF