Seminar Speaker – Sarah M. Aarons, UCSD Scripps |

Seminar Title – When it’s dusty, it’s dusty: Geochemical insights into the modern and paleo dust cycle | 

Abstract – The generation and transport of mineral dust is strongly related to climate on seasonal, year-to-year, and glacial-interglacial timescales. Mineral dust records climate conditions, and influences climate both directly and indirectly. The production and transport of dust is amplified by global and regional droughts, and can be an important source of critical nutrients capable of enhancing primary productivity in both terrestrial and marine environments. In this seminar, I will discuss dust compositional variations to a montane ecosystem in the context of catastrophic drought conditions, and the role of dust as a source of nutrients to this site. Another aspect of the dust cycle is its behavior on longer timescales; changes in the composition of dust trapped in Antarctic ice provide evidence of past atmospheric circulation and earth surface conditions. I will discuss the sources and transport pathways of dust to the Taylor Glacier, East Antarctica, during several climate periods spanning from the last interglacial period (130,000 years ago) to the present. Distinct dust compositions during separate interglacial periods suggest significant differences in conditions at the dust source areas and a large-scale shift in atmospheric dynamics to this peripheral Antarctic site, perhaps precipitated by deglacial conditions and a reduction of the West Antarctic Ice Sheet. This seminar will detail how I combine chemical compositions and physical characteristics of dust to gain insight into Earth’s atmospheric, marine, and terrestrial history, and to better understand the role of dust upon nutrient availability in modern earth systems.