High-resolution windows into abrupt and millennial-scale changes in climate and ocean since the mid-Pleistocene transition, Santa Barbara basin, California

Two high-resolution, multi-proxy records were produced for ∼ 5-kyr windows at ∼ 290 ka and ∼ 735 ka, from piston cores acquired in Santa Barbara basin, California. These records show that abrupt, millennial- to sub-millennial-scale oscillations in weight % total organic carbon carbonate and, at lower resolution, biogenic silica, have occurred concurrent with climatic changes indicated by delta18O of planktonic foraminifera Globigerina bulloides. These oscillations are similar in magnitude and periodicity to the Dansgaard-Oeschger events observed at Ocean Drilling Program (ODP) Site 893 during Marine Isotopic Stage 3. In both records, the relationships in the proxies suggest higher sea-surface temperatures and productivity, associated with decreased benthic oxygenation during interstadials that, at least at ∼ 290 ka, resulted in anoxic conditions. Combined with ODP Site 893 data, these records provide three almost equally spaced datums for studying high-frequency climate behavior and the sensitivity of oceanic biogeochemical responses since the Mid-Pleistocene Transition.