Glacial-interglacial terrigenous provenance in the southeastern Atlantic Ocean; the importance of deep-water sources and surface currents

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doi: 10.1130/G22252.1
Author(s): Latimer, Jennifer C.; Filippelli, Gabriel M.; Hendy, Ingrid L.; Gleason, James D.; Blum, Joel D.
Author Affiliation(s): Primary:
University of Michigan, Department of Geological Sciences, Ann Arbor, MI, United States
Indiana University-Purdue University at Indianapolis, United States
Volume Title: Geology (Boulder)
Source: Geology (Boulder), 34(7), p.545-548. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613 CODEN: GLGYBA
Note: In English. With GSA Data Repository Item 2006106. 34 refs.; illus., incl. sketch map
Summary: Identifying terrigenous sources in deep-sea sediments may reveal temporal trends in paleocirculation and the relative role of eolian, upwelled, and hemipelagic Fe sources to surface waters. Bulk elemental and isotopic geochemistry of deep-sea sediments recovered during Ocean Drilling Program Leg 177 in the southeastern Atlantic sector of the Southern Ocean reveal several important aspects of paleocirculation and terrigenous provenance. The sites studied span 43°-53°S and represent different oceanographic settings relative to regional hydrography and sediment type. Bulk sediment geochemistry indicates that terrigenous provenance varied over the past 600 k.y. Site 1089, the northernmost site, exhibits clear glacial-interglacial variability in provenance, while provenance appears to vary regardless of climate state at the more southerly sites (Site 1093 and 1094). Nd and Sr isotopes and Sm/Nd ratios of the terrigenous fraction indicate that study sites have geochemically distinguishable provenance. Nd and Sr isotopes further suggest that Sites 1089 and 1094 both contain detrital components that originated in South America over the past 30 k.y.; however, Site 1089 is also influenced by southern African sources and the strength of the Agulhas Current. The εNd data support a more hemipelagic source for the terrigenous material rather than an eolian source based on comparisons with Antarctic ice core data and known sea-ice extent.
Year of Publication: 2006
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Absolute age; Agulhas Current; Alkaline earth metals; Aluminum; Antarctica; Atlantic Ocean; Cenozoic; Chemical ratios; Correlation; Currents; Dates; Deep-sea environment; Deep-water environment; Geochemistry; Glacial environment; Glaciomarine environment; Hemipelagic environment; Ice; Ice cores; Interglacial environment; Iron; Isotope ratios; Isotopes; Leg 177; Marine environment; Marine sediments; Metals; Nd-144/Nd-143; Neodymium; ODP Site 1089; ODP Site 1094; Ocean Drilling Program; Ocean currents; Paleo-oceanography; Paleocirculation; Provenance; Quaternary; Rare earths; Sea ice; Sediments; Sm/Nd; South Atlantic; Southeast Atlantic; Southern Ocean; Sr-87/Sr-86; Stable isotopes; Strontium; Terrigenous materials; Titanium
Coordinates: S405611 S405611 E0095338 E0095338
S531049 S531049 E0050749 E0050749
Record ID: 2006058814
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States