Faculty Candidate Seminar - Sarah Aarons

04/24/2018 - 1:00pm
Eckart Lecture Hall room 227
Event Description: 


DATE:          April 24th, Tuesday, 1p.m.  

LOCATION:     Eckart Lecture Hall
SPEAKER:      Sarah Aarons, Ph.D.
            University of Chicago

TITLE:          A tale of two transitions: Geochemical evidence for WAIS collapse during the last interglacial


Documenting the stability of the West Antarctic Ice Sheet (WAIS) during past interglacial periods is critical for accurately predicting future sea-level rise due to climate change. However, proxy records of WAIS extent are limited, despite its large influence on regional environmental conditions. Fluctuations in the composition of dust particles trapped in ice during glacial and interglacial periods provide insight into past wind directions and ice sheet extent. In this talk, I will present results from an ice-core dust archive extracted from the Taylor Glacier in coastal East Antarctica. This archive provides a record of changing dust sources and wind directions strongly influenced by the extent of the nearby WAIS. Radiogenic strontium and neodymium isotopes serve as a “fingerprint” for determining dust provenance, and reveal that the dust composition during the last interglacial period, Marine Isotope Stage (MIS) 5e, is dominated by a young volcanic signature from the West Antarctic Rift System. In contrast, current, pre-industrial, and MIS 1 dust composition is consistent with a mixture of older, reworked continental material from southern South America and nearby Victoria Land. Based on the coastal location of Taylor Glacier and comparison to other interior Antarctic dust records, the change in dust provenance requires a profound difference in atmospheric transport pathways and environmental conditions. Such distinctions are strictly related to the WAIS extent, and I will discuss how this dust record provides evidence of a WAIS collapse early in MIS 5e.


 Faculty Host:  Jane Willenbring (jwillenbring@ucsd.edu)
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