Geological Sciences Seminar: Isla Castaneda, University of Massachusetts, Amherst
- Tuesday, Oct 6, 2020 12:00 PM
- More Info:
- Faculty/Staff, Students, Alumni/Friends
- Department of Geological Science
Reconstructing the paleoclimate history of Lake El’gygytgyn (Far East Russia): new insights from bacterial membrane lipids and plant leaf waxes.
The regional response of the high Arctic to past climate variability is little known prior to ~100,000 years ago. In 2009, a 3.6 Ma sediment core was recovered from Lake El’gygytgyn (Russia), the largest and oldest unglaciated Arctic lake basin. These sediments offer a unique opportunity to examine Plio-Pleistocene high-latitude continental climate variability. Determining the magnitude of past Arctic temperature and precipitation variability is especially relevant to understanding the mechanisms and feedbacks contributing to arctic amplification. Here results of ongoing organic geochemical analyses of Lake El’gygytgyn sediments are presented spanning the past 3.6 Ma, with a main focus on the past 800,000 years of the record (currently analyzed at the highest-resolution). Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are used to reconstruct past temperature and plant leaf wax hydrogen isotopes are used as a proxy for both temperature and for past shifts in moisture source. Our organic geochemical reconstructions suggest that prior to approximately 2.5 Ma, Lake El’gygytgyn was characterized by significantly different limnological and environmental conditions from today. In the Pleistocene, our paleoclimate reconstructions indicate strong glacial-interglacial variability throughout the record with Marine Isotope Stage (MIS) 7 standing out as the strongest interglacial of the past ~ 1 Ma. We compare our new records other previously generated proxy data from Lake El’gygytgyn and find that the intensity and timing of climatic cycles varies by proxy type, even within the same sedimentary archive and when measured on the same samples. We suggest high resolution, multi-proxy analysis of paleoclimate archives is essential for improved understanding of the complexities of the earth climate system as these differences can provide valuable information about climate and environmental patterns and dynamics.
Isla Castaneda's Bio:
1999 BSc Syracuse University (Geology major)
2001 MSc University of Colorado Boulder (Geosciences)
2001-2003 worked at USGS in Denver
2007 PhD University of Minnesota (Geology)
2007-2011 Postdoctoral research associate at the Royal Netherlands Institute for Sea Research
2011-present UMass Amherst (currently Associate Professor with a joint appointment in the Department of Geosciences and Commonwealth Honors College)
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