Pliocene-Pleistocene paleoproductivity on the Wilkes Land margin, Antarctica

Although the East Antarctic Ice Sheet (EAIS) is considered relatively stable, the Wilkes Land Margin (WLM) is susceptible to global warming because its marine-based glaciers are at risk of contact with warm mid-depth waters. Unstable ice sheets cause sea-level rise and threaten coastal communities, but our understanding of ice variability and response to climate change is poorly constrained due to the scarcity of proximal reconstructions. We present a Plio-Pleistocene biogenic silica stratigraphy and diatom assemblages from a marine sediment core collected from IODP site U1361A, located on the WLM continental rise. Characterizing Southern Ocean conditions from 1.8 - 3.8 Ma allows us to examine the shift from the warm Pliocene, which is an analog for future warming conditions, to the cooler Pleistocene, and may improve the parameterization of EAIS response to climate forcings. High wt% BSi intervals are interpreted to reflect interglacial episodes of elevated diatom productivity, while lower wt% BSi intervals are interpreted to reflect glacial episodes of decreased productivity and/or increased terrigenous input. Diatom assemblages from mid- and late-Pliocene interglacial intervals indicate the onset of interglacial surface ocean cooling around 3.6 Ma, punctuated by short-lived warm water incursions.