Early Paleogene variations in the calcite compensation depth; new constraints using old borehole sediments from across Ninetyeast Ridge, central Indian Ocean

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doi: 10.5194/cp-11-473-2015
Author(s): Slotnick, B. S.; Lauretano, V.; Backman, J.; Dickens, G. R.; Sluijs, A.; Lourens, L. J.
Author Affiliation(s): Primary:
Rice University, Department of Earth Sciences, Houston, TX, United States
Utrecht University, Netherlands
Stockholm University, Sweden
Volume Title: Climate of the Past
Source: Climate of the Past, 11(3), p.473-493. Publisher: Copernicus, Katlenburg-Lindau, International. ISSN: 1814-9324
Note: In English. 99 refs.; illus., incl. strat. cols., 1 table, sketch map
Summary: Major variations in global carbon cycling occurred between 62 and 48 Ma, and these very likely related to changes in the total carbon inventory of the ocean-atmosphere system. Based on carbon cycle theory, variations in the mass of the ocean carbon should be reflected in contemporaneous global ocean carbonate accumulation on the seafloor and, thereby, the depth of the calcite compensation depth (CCD). To better constrain the cause and magnitude of these changes, the community needs early Paleogene carbon isotope and carbonate accumulation records from widely separated deep-sea sediment sections, especially including the Indian Ocean. Several CCD reconstructions for this time interval have been generated using scientific drill sites in the Atlantic and Pacific oceans; however, corresponding information from the Indian Ocean has been extremely limited. To assess the depth of the CCD and the potential for renewed scientific drilling of Paleogene sequences in the Indian Ocean, we examine lithologic, nannofossil, carbon isotope, and carbonate content records for late Paleocene - early Eocene sediments recovered at three sites spanning Ninetyeast Ridge: Deep Sea Drilling Project (DSDP) Sites 213 (deep, east), 214 (shallow, central), and 215 (deep, west). The disturbed, discontinuous sediment sections are not ideal, because they were recovered in single holes using rotary coring methods, but remain the best Paleogene sediments available from the central Indian Ocean. The δ13C records at Sites 213 and 215 are similar to those generated at several locations in the Atlantic and Pacific, including the prominent high in δ13C across the Paleocene carbon isotope maximum (PCIM) at Site 215, and the prominent low in δ13C across the early Eocene Climatic Optimum (EECO) at both Site 213 and Site 215. The Paleocene-Eocene thermal maximum (PETM) and the K/X event are found at Site 213 but not at Site 215, presumably because of coring gaps. Carbonate content at both Sites 213 and 215 drops to <5% shortly after the first occurrence of Discoaster lodoensis and the early Eocene rise in δ13C (∼52 Ma). This reflects a rapid shoaling of the CCD, and likely a major decrease in the net flux of 13C-depleted carbon to the ocean. Our results support ideas that major changes in net fluxes of organic carbon to and from the exogenic carbon cycle occurred during the early Paleogene. Moreover, we conclude that excellent early Paleogene carbonate accumulation records might be recovered from the central Indian Ocean with future scientific drilling.
Year of Publication: 2015
Research Program: DSDP Deep Sea Drilling Project
IODP Integrated Ocean Drilling Program
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 06 Petrology, Sedimentary; 12 Stratigraphy, Historical Geology and Paleoecology; Algae; Assemblages; Basalts; Bathymetry; Biochronology; Biostratigraphy; Biozones; Boreholes; C-13/C-12; Calcite; Carbon; Carbon cycle; Carbonate compensation depth; Carbonates; Cenozoic; Chemical composition; Cocos Basin; Cores; DSDP Site 213; DSDP Site 214; DSDP Site 215; DSDP Site 259; DSDP Site 577; Deep Sea Drilling Project; Deep-sea sedimentation; Depositional environment; East Pacific; Expedition 320; Expedition 329; Expeditions 320/321; Floral list; Geochemical cycle; IODP Site U1331; IODP Site U1370; IPOD; Igneous rocks; Index fossils; Indian Ocean; Integrated Ocean Drilling Program; Isotopes; Leg 121; Leg 123; Leg 179; Leg 199; Leg 208; Leg 22; Leg 27; Leg 86; Lithofacies; Lower Paleogene; Magnetostratigraphy; Marine sedimentation; Marine sediments; Microfossils; Mid-Indian Basin; Nannofossils; Ninetyeast Ridge; North Pacific; Northeast Pacific; O-18/O-16; ODP Site 1107; ODP Site 1215; ODP Site 1219; ODP Site 1220; ODP Site 1262; ODP Site 756; ODP Site 757; ODP Site 766; Ocean Drilling Program; Organic carbon; Oxygen; Pacific Ocean; Paleo-oceanography; Paleocene-Eocene Thermal Maximum; Paleogene; Paleomagnetism; Plantae; Reconstruction; Relative age; Sea-level changes; Sedimentation; Sediments; Simulation; South Pacific; Southeast Pacific; Stable isotopes; Stratigraphic gaps; Subsidence; Tertiary; Tholeiitic basalt; Volcanic rocks; Wharton Basin
Coordinates: S150000 S020000 E1000000 E0780000
Record ID: 2015071086
Copyright Information: GeoRef, Copyright 2020 American Geosciences Institute. Reference includes data from Copernicus Gesellschaft, Katlenburg-Lindau, Germany