HR: 1330h
AN: PP42A-0863    [PDF]
TI: Rapid Variations in the Biogeochemistry of the Arabian Sea Determined Using Multi-proxy Comparisons From Indian and Somali Margin Cores Over the Last 60 kyr.
AU: * Ivanochko, T S
EM: Tara.Ivanochko@glg.ed.ac.uk
AF: School of GeoSciences, University of Edinburgh, Grant Institute, Kings Buildings, West Mains Rd., Edinburgh, EH9 3JW United Kingdom
AU: Ganeshram, R
EM: Raja.Ganeshram@glg.ed.ac.uk
AF: School of GeoSciences, University of Edinburgh, Grant Institute, Kings Buildings, West Mains Rd., Edinburgh, EH9 3JW United Kingdom
AU: Fontugne, M
EM: Michel.Fontugne@lsce.cnrs-gif.fr
AF: Laboratoire des Sciences du Climat et de l'Environnement, Domaine du CNRS, Gif sur Yvette Cedex, F 91198 France
AB: Evidence of rapid change in the biogeochemistry of the Arabian Sea throughout the Holocene in addition to the Last Glacial period has been reconstructed using two marine sediment cores. A Somali margin core (1567 m water depth) is compared to one from the Indian margin (1230 m water depth). Today, the basin wide oxygen minimum zone results in denitrification within the intermediate waters of the Arabian Sea. Using past variations in the basin-wide denitrification signal to temporally relate these two cores, changes in the biogeochemical proxies of the east and west basin are compared. Throughout the Holocene, %organic carbon and Ba/Al records suggest large fluctuations in productivity. As well, major element (Mg/Al, P/Al, K/Al) ratios indicate the Arabian Sea biogeochemistry has experienced significant variation over the last 10,000 years. Within each core, millennial-scale variations in organic proxies (%organic carbon, Ba/Al) during the last glacial period are compared with sedimentary redox conditions (Mo/Al), %CaCO3, Sr/Al and Mg/Al to identify changes paleoproductivity and carbonate preservation. Mineralogy downcore provides further evidence of carbonate preservation and, in conjunction with major element ratios (Ti/Al, K/Al) the varying dust sources at the two sites.
DE: 4215 Climate and interannual variability (3309)
DE: 4267 Paleoceanography
DE: 4825 Geochemistry
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting