Dust transport to Antarctica during previous warm periods

Abstract:

Understanding variations in dust transport, both in amount and composition, is essential for understanding the links between climate, biogeochemical cycling, and landscape evolution through time. The composition and flux of dust to the Antarctic during glacial regimes is relatively well known because of higher dust transport during cold periods. In contrast, determining the source of dust during previous interglacial periods is more challenging due to the lower dust transported and the limited amount of ice available for measurement. Dust provenance in Antarctic ice core records indicate that South America is the primary source during both glacial and interglacial periods, however records from the peripheral portion of East Antarctica hint at different source contributor. Here, we present an Antarctic ice core record of dust flux and dust provenance (Sr and Nd isotope compositions) for two glacial-interglacial transitions at the Taylor Glacier. While South American and local Antarctic dust is a consistent contributor during the Holocene, the dust record from the last interglacial period (~130-116 ka) is uniquely volcanic in composition. Dust concentration data suggest that the volcanic signature is not related to isolated volcanic eruptions, but rather the sustained transport of volcanic dust. We consider potential causes for the transport of uniquely volcanic material, including increased subaerial exposure of nearby sediment from the West Antarctic Rift System and large-scale circulation changes. The difference in the dust composition from the last interglacial period to the Holocene at the same site require a profound difference in atmospheric transport and environmental conditions, which could be plausibly related to ice sheet extent and/or retreat. We place our dataset into geographic context in this peripheral portion of East Antarctica to highlight additional records that may aid in constraining the extent of deglaciation and the impact on the Southern Hemisphere dust cycle.