Planktonic foraminiferal d18O, pollen, and opal records from Santa Barbara
Basin are used to evaluate climate changes in the northeast Pacific during
marine isotope stages (MIS) 6 and 5. While the oak and foraminifera record the
major glacial-interglacial changes, opal is not correlated with these
large-scale transitions. Surface water warming in the basin was synchronous
with terrestrial ... warming but earlier than ice sheet melting and increasing
Northern Hemisphere insolation at Termination II. During and immediately after
deglaciation, our marine proxies indicate the presence of an isothermal upper
water column. Later in substage 5E, the water column thermally stratified,
surface productivity increased, and laminated sediments began accumulating.
Sediment trap and hydrographic data suggest these changes were due to the
onset of a strong seasonal cycle similar to that seen today in the basin. A
series of rapid coolings within MIS 5 appears to be synchronous with North
Atlantic ice-rafting events and Greenland stadials.