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Lake Sediment Records of
Holocene Climate Variability in Central Asia:
I am currently
reconstructing Holocene environmental changes in Central Asia using sediment
records from multiple lake
systems. This research program
builds upon the success of a number of U.S.-led and joint
German-Mongolian-Russian field expeditions. We are
examining laminated sediment records from two sites in
Mongolia, and decadal to century-scale environmental changes from nearly
forty additional lake sediment core sites along east-west and
north-south environmental gradients in Mongolia, northern and
southeastern Kazakhstan,
and southern Siberia. Geochemical assays (carbonate mineral oxygen and
carbon isotopic analyses) and
sedimentological (scanning XRF, rock-magnetic) and biological
(diatoms, photosynthetic pigments, fossil pollen) studies of the
sediment cores are providing information on the local and regional extent
of regional Holocene climate transitions. This study will also provide
insight into the external and internal forcing mechanisms of extreme
continentality and abrupt changes within the Asian interior and will
provide insight on twentieth century warming by extending proxy data
beyond existing instrumental and tree-ring records.
The most recent
component of this collaborative project included paleoenvironmental field
research within the Russian Federation (Chelyabinsk Oblast and the
Republic of Bashkortostan) during a three-week period in late June and
July 2008. During the field campaign, we recovered multiple sediment cores
from five lake sites located along the eastern slope of the southern
Ural Mountains (along a north-south transect that spanned ~190 km).
Waters of the study lakes are rich in carbonate and bicarbonate and
thereby promote shell formation. Because of the high density of
carbonate microfossils (ostracode and gastropod shells) preserved in the
sediments of the lakes, we expect to generate stable isotope
data sets that, when coupled with sedimentological and biological
analyses, will provide valuable climate information and thereby an
environmental context for the emergence of a complex socio-economic
formation in the Eurasian steppe region.
Related Programs:
Carnegie Museum of Natural History - Department of Anthropology (Dr.
Sandra Olsen)
Kent State University - Department of Geology (Dr. Joseph Ortiz)
National
University of Mongolia - Faculty of Biology (Dr.
Soninkhishig Nergui)
National
University of Mongolia - Mongolian Landscape Research Centre (Dr.
Michael Walther)
University of Akron - Department of Geology and Environmental Science (Dr. John
Peck)
University of Pittsburgh - Department of Anthropology (Dr.
Bryan Hanks)
Washington University in St. Louis - Department of Anthropology (Dr.
Michael Frachetti)
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