Late Pleistocene surface and thermocline conditions of the eastern tropical Indian Ocean
Journal
Quaternary Science Reviews
Journal Volume
29
Journal Issue
44750
Pages
887-896
Date Issued
2010
Author(s)
Abstract
Surface and thermocline conditions of the eastern tropical Indian Ocean were reconstructed through the past glacial-interglacial cycle by using Mg/Ca and alkenone-paleothermometry, stable oxygen isotopes of calcite and seawater, and terrigenous fraction performed on sediment core GeoB 10038-4 off SW Sumatra (∼6°S, 103°E, 1819 m water depth). Results show that annual mean surface and thermocline temperatures varied differently and independently, and suggest that surface temperatures have been responding to southern high-latitude climate, whereas the more variable thermocline temperatures were remotely controlled by changes in the thermocline temperatures of the North Indian Ocean. Except for glacial terminations, salinity proxies indicate that changing intensities of the boreal summer monsoon did not considerably affect annual mean conditions off Sumatra during the past 133,000 years. Our results do not show a glacial-interglacial pattern in the thermocline conditions and reject a linear response of the tropical Indian Ocean thermocline to mid- and high-latitude climate change. Alkenone-based surface temperature estimates varied in line with the terrigenous fraction of the sediment and the East Asian winter monsoon proxy records at the precession band suggestive of monsoon (sea level) to be the dominant control on alkenone temperatures in the eastern tropical Indian Ocean on sub-orbital (glacial-interglacial) timescales. © 2009 Elsevier Ltd. All rights reserved.
SDGs
Other Subjects
Alkenones; Annual mean; East Asian winter monsoon; Glacial terminations; Glacial-interglacial cycles; In-line; Indian ocean; Late Pleistocene; Linear response; Proxy records; Sediment core; Stable oxygen isotopes; Sumatra; Summer monsoon; Surface temperatures; Thermocline temperature; Time-scales; Tropical Indian ocean; Water depth; Atmospheric temperature; Carbonate minerals; Glacial geology; Isotopes; Oxygen; Sea level; Seawater; Sedimentology; Sediments; Stream flow; Surface properties; Tropics; Climate change; alkenone; calcium; glacial-interglacial cycle; magnesium; oxygen isotope; paleoceanography; paleotemperature; Pleistocene; reconstruction; salinity; sea level; sea surface temperature; sediment core; terrigenous deposit; thermocline; Greater Sunda Islands; Indian Ocean; Indian Ocean (North); Indian Ocean (Tropical); Sumatra; Sunda Isles
Type
journal article