Sediment cores and their radiocarbon ages in the Western Ross Sea, Antarctica

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We describe paleoenvironmental changes related to ice sheet and ice shelf developments in the western Ross Sea in the late Quaternary, based on the three sediment cores collected along ca 167°E We distinguish four lithologic units in their sequences as follows (1) Unit I of diatomaceous mud, (2) Unit IIA of mud, (3) Unit IIB of alternating clay and thin laminated silt, and (4) Unit III of consolidated sandy silt with pebbly gravel Interpreted sedimentary environments based on the time constraints of fifteen AMS ^<14>C dates and characteristics of sediments and diatom assemblages, are summarized as follows (1) Prior to the ice sheet advance, this area was possibly under a marine environment, (2) the grounded ice sheet is thought to have advanced between 35 and 20 ka BP, (3) shelf ice possibly covered the southern site between 25 and 20 ka BP, (4) an open marine environment with moderate productivity existed from 20 ka BP at the northern site, and (5) an open marine environment with high productivity existed from 9kaBP The length and timing of the ice sheet advance cannot explain radiocarbon dates of all sites Radiocarbon dating of marine sediments in the Antarctic area shows a large reservoir effect and contamination of reworked dead carbon In our estimation of the ages, two thousand years correction is needed in the upper unit at least Age data for lower units are thought to be older than the true sedimentary ages though these need further consideration
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Sediment cores and their radiocarbon ages in the Western Ross Sea, Antarctica

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