Recurrent E - W oscillations of the ice flow confluence of the East and West Antarctic ice sheets in the central Ross Sea, Antarctica, from the Middle Miocene to the present day

We present a multidisciplinary provenance study on legacy cores drilled in the 1970s during DSDP Leg 28 at sites 271 and 272, in the central Ross Sea, Antarctica. The two sites combined provide a discontinuous glaciomarine sedimentary record covering 18 myr, from the Middle Miocene to the present day.The two boreholes are located on the continental shelf and near the edge of the Ross Ice Shelf, in the middle of the Ross Sea, at a key site close at 180° longitude that is considered to represent the present confluence between ice flows fed by West Antarctica and East Antarctica. The study employs Usingle bondPb dating of detrital zircons and apatites, coupled with apatite fission-track dating and trace element and REE compositions. Based on the sedimentary provenance, our data show a recurrent E-W oscillation of the confluence of the West Antarctica and East Antarctica ice flows, allowing phases of advance and retreat of the West Antarctic Ice Sheet to be inferred.