2026-10-15T11:08:28Z https://oai.datacite.org/oai

doi:10.1594/pangaea.707452 2024-07-20T17:55:11Z PANGAEA PANGAEA.REPOSITORY

Physical properties and bulk organic geochemical results for sediments from DSDP Hole 96-619 Jasper, John P Gagosian, Robert B PANGAEA 1990 Collected: 1983-10-21T00:00:00 Issued: 1990 doi:10.1016/0016-7037(90)90443-o Drilling/drill rig Leg96 Glomar Challenger Deep Sea Drilling Project (DSDP) The concentration and carbon isotopic composition (d13C) of sedimentary organic carbon (C_org), N/C ratios, and terrigenous and marine d13C_org endmembers form a basis from which to address problems of Late Quaternary glacial-interglacial climatic variability in a 208.7 m hydraulic piston core (DSDP 619) from the Pigmy Basin in the northern Gulf of Mexico. While interpretations of sedimentary d13C_org time series records are often not unique, paired analyses of d13C_org and N/C are consistent with the hypothesis that the C_org in the Pigmy Basin is a climatically determined mixture of C3-photosynthetic terrigenous and marine organic matter, confirming the earlier d13C_org model of Sackett (1964). A high resolution (~1.4-2.9 Ka/sample) d13C_org record shows that sedimentary organic carbon in interglacial oxygen isotope (sub)stages 1 and 5a-b are enriched in 13C (average +/-1 sigma values are -24.2+/-1.2‰ and -22.9+/-0.7‰ relative to PDB, respectively) while glacial isotope stage values 2 are relatively depleted (-25.6+/-0.5‰). Concentrations of terrigenous and marine sedimentary organic carbon are calculated for the first time using d13C_org and C_org measurements, and empirically determined terrigenous and marine d13C_org endmembers. The net accumulation rate of terrigenous organic carbon is 4.3+/-2.6 times higher in isotope stages 2-4 than in (sub)stages 1 and 5a-b, recording higher erosion rates of terrigenous organic material in glacial times. The concentration and net accumulation rates of marine and terrigenous C_org suggest that the nutrient-bearing plume of the Mississippi River may have advanced and retreated across the Pigmy Basin as sea level fell and rose in response to glacial-interglacial sea level change. Supplement to: Jasper, John P; Gagosian, Robert B (1990): The sources and deposition of organic matter in the late Quaternary Pigmy Basin, Gulf of Mexico. Geochimica et Cosmochimica Acta, 54(4), 1117-1132 en Collection Supplementary Publication Series of Datasets application/zip Creative Commons Attribution 3.0 Unported https://creativecommons.org/licenses/by/3.0/legalcode