Chase, Z. Lamont-Doherty Earth Observatory, zanna@ldeo.columbia.edu
Fleisher, M. Lamont-Doherty Earth Observatory, martyq@ldeo.columbia.edu
Anderson, R. F. Lamont-Doherty Earth Observatory, boba@ldeo.columbia.edu

 
PRESERVATION AND BURIAL OF OPAL IN THE SW PACIFIC SECTOR OF THE SOUTHERN OCEAN
 
Sediments record the integrated response of carbon flux to changes in climate and other factors, such as trace element supply, which may regulate phytoplankton growth and species composition. Opal is the principal biogenic phase in Southern Ocean sediments but reconstructing past changes in diatom production from opal burial rates is confounded because: (1) dissolution of opal during early diagenesis is extensive, but poorly constrained, and (2) focusing of sinking particles by the deep-reaching Antarctic Circumpolar Current decouples burial and rain rate. Here we normalize opal to Th-230 to correct for sediment focusing. Th-normalized opal accumulation rates will be compared to opal fluxes collected by sediment traps as part of the U.S. JGOFS program to evaluate the fraction of the opal rain preserved and buried along the JGOFS transect at 170W. Maximum opal rain today in this region occurs between approximately 60S and 65S.Using down-core records of Th-normalized opal accumulation rate, we will assess the response of opal rain to climate change since the Last Glacial Maximum, both in terms of the magnitude of opal rain and the extent of the northward migration of the opal belt.
 
Day: Friday, Feb. 5
Time: 04:30 - 04:45pm
Location: Sweeney Center
 
Code: SS31FR0430S