Tiny but mighty: Geochemical and physical characteristics of mineral dust from Allan Hills ice cores
Mineral dust records from Antarctic ice cores offer insights into past atmospheric circulation and Earth surface conditions. In this talk, we will explore the dust records from two ice cores obtained at the Allan Hills Blue Ice Area in East Antarctica. One core (ALHIC1903) contains ice spanning MIS 6 to 5e in stratigraphic order, while the other (ALHIC1901) contains discontinuous ice spanning 4000-500 ka. Here, we applied a suite of geochemical and physical measurements galore. These data both expand and extend the Antarctic ice core dust record to under sampled and unexamined time periods, which previously was limited to 800 ka. During the Last Interglacial (MIS 5e), the unique dust composition combined with Earth System model simulations suggest reorganized atmospheric circulation consistent with an open Ross Sea and/or diminished West Antarctic Ice Sheet. In contrast, the older discontinuous ice core appears altered possibly by entrainment of basal material near the bed, and shallower depths appear to be time-averaged contributions from glacial and interglacial sources. Together, these data demonstrate how mineral dust preserved within Antarctic ice can be used to gain insight into past environmental conditions and ice stratigraphy and to reconstruct ice sheet extent/retreat during past warm periods.
