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Isotopic evidence for Younger Dryas aridity in the North American Midcontinent

J. A. Dorale, L. A. Wozniak, E. A. Bettis, 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 (Boulder) (June 2010) 38 (6): 519-522


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 (delta (super 13) C) 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 delta (super 13) C signature of soil organic matter is a reliable indicator of past climatic change because delta (super 13) C values are controlled primarily by the relative abundance of C (sub 3) and C (sub 4) plants, which is tied to the environmental setting. Between ca. 13,200 and 11,900 yr ago, the abundance of C (sub 4) 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 C (sub 4) -rich prairie existed in southwestern Missouri, spruce forests grew in Iowa, Illinois, and Ohio.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 38
Serial Issue: 6
Title: Isotopic evidence for Younger Dryas aridity in the North American Midcontinent
Affiliation: University of Iowa, Department of Geoscience, Iowa City, IA, United States
Pages: 519-522
Published: 201006
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 36
Accession Number: 2010-050213
Categories: Quaternary geologyIsotope geochemistry
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sketch map
N37°17'60" - N37°36'00", W94°04'60" - W93°39'00"
Secondary Affiliation: University of Kansas, USA, United StatesIllinois State Museum, USA, United StatesMissouri State University, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201027
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