Middle to Late Pleistocene Record of Dust Input during Glacial Periods in Western Australia shelf (IODP Expedition 356, Site U1461)

IODP Expedition 356 Site U1461 represents one of the few records in the NW sector of the Australian shelf that provides information about aridity fluctuations in Australia during major glacial cycles of the Quaternary because of its proximity to the continent. A combination of chronostratigraphic indicators revealed the (partial) preservation of two major glaciations (MIS 2 and MIS 12) in the sedimentary record. The faunal content (mainly benthic foraminifera, corals and bryozoans) was analyzed to estimate paleo-environments and paleo-depths in order to determine if these sediments have been remobilized by reworking processes. Despite the occurrence of a depositional hiatus (including parts of the MIS 2 and the whole of MIS 3 to MIS 7 time interval), the excellent preservation of faunal content suggests that the preserved sediment can be considered in situ. The geochemical composition of the sediments (Nd and major elements) indicates that during MIS 12, riverine input was likely reduced because of enhanced aridity, and the sediment provenance (mainly atmospheric dust) might come from the Central (Lake Eyre) or the eastern (Murray Darling Basin) parts of the continent. MIS 2 is confirmed to be one of the driest periods recorded in Australia but with mixed dust sources from the eastern and western parts of the continent. More humid conditions followed the glacial maximum which might correspond to the peak of the Indian-Australian Summer Monsoon