Orbital forcing of organic carbon burial in the proto-North Atlantic during oceanic anoxic event 2

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doi: 10.1016/j.epsl.2004.09.037
Author(s): Kuypers, Marcel M. M.; Lourens, Lucas J.; Rijpstra, W. Irene C.; Pancost, Richard D.; Nijenhuis, Ivar A.; Sinninghe Damsté, Jaap S.
Author Affiliation(s): Primary:
Netherlands Institute for Sea Research, Department of Marine Biogeochemistry and Toxicology, Den Burg, Netherlands
Utrecht University, Netherlands
Volume Title: Earth and Planetary Science Letters
Source: Earth and Planetary Science Letters, 228(3-4), p.465-482. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X CODEN: EPSLA2
Note: In English. Includes appendices. 64 refs.; illus., incl. sketch map
Summary: The Cenomanian/Turonian (C/T) intervals at DSDP Sites 105 and 603B from the northern part of the proto-North Atlantic show high amplitude, short-term cyclic variations in total organic carbon (TOC) content. The more pronounced changes in TOC are also reflected by changes in lithology from green claystones (TOC<1%) to black claystones (TOC>1%). Although their depositional history was different, the individual TOC cycles at Sites 105 and 603B can be correlated using stable carbon isotope stratigraphy. Sedimentation rates obtained from the isotope stratigraphy and spectral analyses indicate that these cycles were predominately precession controlled. The coinciding variations in HI, OI, δ13Corg and the abundance of marine relative to terrestrial biomarkers, as well as the low abundance of lignin pyrolysis products generated from the kerogen of the black claystones, indicate that these cyclic variations reflect changes in the contribution of marine organic matter (OM). The cooccurrence of lamination, enrichment of redox-sensitive trace metals and presence of molecular fossils of pigments from green sulfur bacteria indicate that the northern proto-North Atlantic Ocean water column was periodically euxinic from the bottom to at least the base of the photic zone (<150 m) during the deposition of the black claystones. In contrast, the green claystones are bioturbated, are enriched in Mn, do not show enrichments in redox-sensitive trace metals and show biomarker distributions indicative of long oxygen exposure times, indicating more oxic water conditions. At the same time, there is evidence (e.g., abundance of biogenic silica and significant 13C-enrichment for OC of phytoplanktic origin) for enhanced primary productivity during the deposition of the black claystones. We propose that increased primary productivity periodically overwhelmed the oxic OM remineralisation potential of the bottom waters resulting in the deposition of OM-rich black claystones. Because the amount of oxygen used for OM remineralisation exceeded the amount supplied by diffusion and deep-water circulation, the northern proto-North Atlantic became euxinic during these periods. Both Sites 105 and 603B show trends of continually increasing TOC contents and HI values of the black claystones up section, which most likely resulted from both enhanced preservation due to increased anoxia and increased production of marine OM during oceanic anoxic event 2 (OAE2). Abstract Copyright (2004) Elsevier, B.V.
Year of Publication: 2004
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
Key Words: 06 Petrology, Sedimentary; 12 Stratigraphy, Historical Geology and Paleoecology; Anaerobic environment; Atlantic Ocean; Biomarkers; Black shale; Burial; C-13/C-12; Carbon; Carbon cycle; Cenomanian; Clastic rocks; Climate forcing; Cretaceous; Cyclic processes; DSDP Site 105; DSDP Site 367; DSDP Site 603; Deep Sea Drilling Project; Eh; Foraminifera; Geochemical cycle; Geochemistry; Globigerinacea; IPOD; Invertebrata; Isotope ratios; Isotopes; Leg 11; Leg 41; Leg 93; Mesozoic; Metals; Microfossils; North Atlantic; Orbital forcing; Organic carbon; Organic compounds; Paleo-oceanography; Paleoenvironment; Paleogeography; Protista; Pyrolysis; Rotaliina; Rotalipora; Sedimentary rocks; Sedimentation; Sedimentation rates; Stable isotopes; Total organic carbon; Trace elements; Turonian; Upper Cretaceous; Variations
Coordinates: N345343 N345343 W0691024 W0691024
N352939 N352940 W0700142 W0700143
N122913 N122913 W0200250 W0200250
Record ID: 2006014428
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands