Composition and circulation of bottom water in the western Atlantic Ocean during the last glacial, based on pore-water analyses from the Amazon Fan

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doi: 10.1130/0091-7613(1999)027<1011:CACOBW>2.3.CO;2
Author(s): Burns, Stephen J.; Maslin, Mark A.
Author Affiliation(s): Primary:
Universität Bern, Geologisches Institut, Bern, Switzerland
University College of London, 26 Bedford Way, United Kingdom
Volume Title: Geology (Boulder)
Source: Geology (Boulder), 27(11), p.1011-1014. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613 CODEN: GLGYBA
Note: In English. 26 refs.; illus., incl. sketch map
Summary: Pore waters from very rapidly deposited continental margin sediments may provide a record of changes in the isotopic and chemical composition of seawater over time. Measurements made on pore waters extracted from sediments drilled at five sites during Ocean Drilling Program Leg 155 on the Amazon Fan show systematic increases in δ18O with depth from ∼0.1 per mil in surface sediments to ∼0.4 per mil in glacial-age sediments from below about 40 m below sea floor. This relatively small glacial-interglacial difference reflects both the overall increase in δ18O of seawater during the last glacial and a change in bottom-water source to the area from North Atlantic Deep Water at present to relatively 18O depleted Antarctic Bottom Water during the last glacial. When combined with δ18O analyses of benthic foraminifers, the pore-water data indicate a glacial-interglacial temperature change of about 4°C.
Year of Publication: 1999
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Amazon Fan; Anomalinidae; Antarctic Bottom Water; Atlantic Ocean; Bottom currents; Brazil; Cassidulinacea; Cenozoic; Chloride ion; Chlorine; Cibicidoides; Cibicidoides wuellerstorfi; Continental margin; Currents; Foraminifera; Geochemistry; Glacial environment; Glaciomarine environment; Halogens; Hydrochemistry; Interglacial environment; Invertebrata; Isotope ratios; Isotopes; Leg 155; Marine environment; Marine sediments; Microfossils; North Atlantic; North Atlantic Deep Water; O-18/O-16; ODP Site 939; ODP Site 940; ODP Site 944; ODP Site 946; Ocean Drilling Program; Oxygen; Paleo-oceanography; Paleocirculation; Paleotemperature; Pore water; Protista; Quaternary; Rotaliina; Sediments; South America; South Atlantic; Southwest Atlantic; Stable isotopes; Submarine fans; Upper Quaternary
Coordinates: N043544 N065701 W0463759 W0490528
N044318 N044318 W0473001 W0473001
Record ID: 1999070132
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