Journal article
Middle to Late Pleistocene loess record in eastern Nebraska, USA, and implications for the unique nature of Oxygen Isotope Stage 2
Quaternary Science Reviews, Vol.26(5-6), pp.773-792
03/01/2007
DOI: 10.1016/j.quascirev.2006.10.007
Abstract
New subsurface data reveal a nearly continuous stratigraphic record of Middle to Late Pleistocene loess sedimentation preserved beneath upland summits in eastern Nebraska, USA. Thickness and grain size trends, as well as pedologic evidence, indicate significant changes in loess sources, accumulation rates, and depositional environments. The newly defined Kennard Formation accumulated in the Middle Pleistocene, and may represent multiple thin increments of distal loess from nonglacial sources on the Great Plains. The overlying Loveland Loess, up to 18 m thick and deposited during Oxygen Isotope Stage 6 (OIS 6) (Illinoian glaciation), probably records the emergence of the Missouri River valley as a major glaciogenic loess source. The prominent Sangamon Geosol formed through long-term pedogenic alteration of the upper Loveland Loess during OIS 5 and 4. Thin loess of the Gilman Canyon Formation records slow loess accumulation and pedogenic alteration in OIS 3. The Peoria Loess (OIS 2) is similar in thickness to Loveland Loess, but may have accumulated more rapidly in an environment less favorable to bioturbation. More importantly, comparison of Peoria and Loveland loess thickness trends indicates much greater influx of nonglaciogenic loess from the Great Plains during OIS 2 than in OIS 6, suggesting colder and/or drier conditions in the Midcontinent during OIS 2 than in earlier glacial stages.
Details
- Title: Subtitle
- Middle to Late Pleistocene loess record in eastern Nebraska, USA, and implications for the unique nature of Oxygen Isotope Stage 2
- Creators
- J. A. MasonR. M. JoeckelE A Bettis III - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Quaternary Science Reviews, Vol.26(5-6), pp.773-792
- DOI
- 10.1016/j.quascirev.2006.10.007
- ISSN
- 0277-3791
- Language
- English
- Date published
- 03/01/2007
- Academic Unit
- Earth and Environmental Sciences
- Record Identifier
- 9983557558702771
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