Title
Isotopic evidence for Younger Dryas aridity in the North American midcontinent
Abstract
Determining the impact of the Younger Dryas (YD) climate event on the unglaciated North American midcontinent has proved difficult due to a scarcity of suitable paleoclimate proxies. Here we present a well-dated carbon isotope (δ13C) record from a buried soil sequence in southwestern Missouri, which reveals a large isotopic excursion during the YD chronozone. In this region of the modern prairie-forest border, the δ13C signature of soil organic matter is a reliable indicator of past climatic change because δ13C values are controlled primarily by the relative abundance of C3 and C4 plants, which is tied to the environmental setting. Between ca. 13,200 and 11,900 yr ago, the abundance of C4 grasses increased by upwards of 50% of the total biomass, indicating expansion of grassland most likely driven by increased aridity during this period. Environmental gradients in the midcontinent must have been very steep, because at the same time that a C4-rich prairie existed in southwestern Missouri, spruce forests grew in Iowa, Illinois, and Ohio.
Department(s)
Center for Archaeological Research
Document Type
Article
DOI
https://doi.org/10.1130/G30781.1
Publication Date
6-1-2010
Recommended Citation
Dorale, J. A., L. A. Wozniak, E. A. Bettis III, S. J. Carpenter, R. D. Mandel, E. R. Hajic, N. H. Lopinot, and J. H. Ray. "Isotopic evidence for Younger Dryas aridity in the North American midcontinent." Geology 38, no. 6 (2010): 519-522.
Journal Title
Geology
