Osmium concentrations and isotope ratios of ODP Site 146-893A

The Pleistocene deposits of Santa Barbara Basin (SBB) show laminations during interglacial periods typical of an anoxic or suboxic depositional environment and more sporadically laminated deposits during glacial times, indicating a more oxic environment of deposition. The 187Os/188Os value of sediment leaches varies as a function of climate, consistent with a more radiogenic Os signal during interglacial times and less radiogenic Os values more typical of glacial times. The signal is confounded by contributions from a high Os detrital component with a variable 187Os/188Os value, but generally agrees with prior result from deposits from other marine environments.