Millennial-scale CaCO₃ and C(org) events along the northern and central California margins: Stratigraphy and origins

Sediments from five Leg 167 drill sites and three piston cores were analyzed for C(org) and CaCo₃. Oxygen isotope stratigraphy on benthic foraminifers was used to assign age models to these sedimentary records. We find that the northern and central California margin is characterized by k.y.-scale events that can be found in both the CaCO₃ and C(org) time series. We show that the CaCO₃ events are caused by changes in CaCO₃ production by plankton, not by dissolution. We also show that these CaCO₃ events occur in marine isotope Stages (MIS) 2, 3 and 4 during Dansgaard/Oeschger interstadials. They occur most strongly, however, on the MIS 5/4 glaciation and MIS 2/1 deglaciation. We believe that the link between the northeastern Pacific Ocean and North Atlantic is primarily transmitted by the atmosphere, not the ocean. Highest CaCO₃ production and burial occurs when the surface ocean is somewhat cooler than the modern ocean, and the surface mixed layer is somewhat more stable.