Collaborative Research: Ice-Age and Millennial-Scale Changes of Pacific Intermediate Waters: Ventilation from the Southern Ocean

99-06778 Pisias 99-07292 Lyle The recommended proposal is for a marine geological field program in the eastern equatorial and subtropical Pacific to study vertical water mass distributions during the late Pleistocene on millennial time scales. The object of the proposed work is to: 1) serve as a site survey for both coring and geophysical data in support of the JOIDES ODP Proposal 465/ADD, currently highly ranked by the JOIDES SCICOM with a strong likelihood of drilling in the year 2001 or 2002; 2) document the acquired sediment cores for investigations of millennial-scale climate and ocean variability in the eastern equatorial Pacific; and 3) test the hypothesis that episodic ventilation of the intermediate waters of the Pacific Basin results from intensified flow of Antarctic Intermediate Water. Intermediate water properties will be examined with benthic foraminiferal species and isotopic data. By examining the timing and spatial distribution of climate events associated with intermediate waters, it will be assessed whether such changes are driven from the Southern or Northern Hemispheres. ***