Paleoceanographic variability on a millennial scale: a high resolution record of the latest deglaciation from the Blake Outer Ridge, western North Atlantic

Submitted in partial fulfillment of the requirements of the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 1998Strong temporal and geographic variabilty in paleocirculation during the latest deglaciation is demonstrated for the Blake Outer Ridge, Western North Atlantic. Cores KNR140-2 GGC-39 from 2975 meters and GGC-40 from 2924 meters show correlative oscillations in Cibicidoides and Uvigerina abundances, and δ180 from Globigerinoides ruber (white) which suggest that the Western Boundary Undercurrent and NADW fluctuated on a decadal to century scale between 14,000 and 10,000 14C years BP. Furthermore, between 13,500 and 13,300 14C years BP and 10,900 and 10,600 14C years BP, the coincidence of benthic foraminifera abundance maxima and benthic δ13C minima from C. wuellerstorfi indicate an increased influence of AABW relative to NADW in the vicinity of 3000 meters on the Blake Outer Ridge.NSF grants which helped to subsidize my work: NSF grants OCE-9301015 for 14C dates at NOSAMS, OCE92- 17017 and OCE95- 10075 for work with Lloyd Keigwin and O.S.P. 26317 for work with Maureen Raymo