California Margin sea surface temperature and paleoproductivity records at Ocean Drilling Program site 1012

A high-resolution sea-surface temperature (SST) record from ODP site 1012 off the California Margin documents the mid/late Pliocene climate shift. The alkenone derived SST record shows the cooling of surface waters in coastal California between the mid Pliocene and early Pleistocene. This cooling trend began prior to the onset of Northern Hemisphere glaciation with significant changes in SST variation starting around 3 Ma. Intensification of glacial SSTs by ∼7°C occurs 3--2 Ma, with cool water SSTs of 19°C at 3 Ma intensifying to SSTs of 12°C at 2.1 Ma. This trend ends abruptly 2.1 Ma as glacial temperatures become milder into the early Pleistocene. Mean SSTs cooled ∼5°C between ∼3 and 2.1 Ma. Measurements of C 37 total indicate an increase in paleoproductivity between 3 and 1.5 Ma. Spectral analysis of both SST and paleoproductivity display the presence of obliquity signals.