Pedothem carbonates reveal anomalous North American atmospheric circulation 70,000-55,000 years ago

EJ Oerter; WD Sharp; JL Oster; A Ebeling; JW Valley; R Kozdon; IJ Orland; J Hellstrom; JD Woodhead; JM Hergt; OA Chadwick; R Amundson

Journal article

Pedothem carbonates reveal anomalous North American atmospheric circulation 70,000-55,000 years ago

EJ Oerter, WD Sharp, JL Oster, A Ebeling, JW Valley, R Kozdon, IJ Orland, J Hellstrom, JD Woodhead, JM Hergt, OA Chadwick, R Amundson

Proceedings of the National Academy of Sciences of the United States of America | Published : 2016

DOI: 10.1073/pnas.1515478113

Abstract

Our understanding of climatic conditions, and therefore forcing factors, in North America during the past two glacial cycles is limited in part by the scarcity of long, well-dated, continuous paleoclimate records. Here, we present the first, to our knowledge, continuous, millennial-resolution paleoclimate proxy record derived from millimeter-thick pedogenic carbonate clast coatings (pedothems), which arewidely distributed in semiarid to arid regions worldwide. Our new multiisotope pedothem record from the Wind River Basin inWyoming confirms a previously hypothesized period of increased transport of Gulf of Mexico moisture northward into the continental interior from 70,000 to 55,000 years ag..

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University of Melbourne Researchers

John Hellstrom Author

Jon Woodhead Author

Janet Hergt Author

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Grants

Awarded by National Science Foundation

Funding Acknowledgements

We thank Ken Ludwig for insights into U-series dating and data analysis, Tim Teague for assistance with sample preparation, Kouki Kitajima for assistance with the WiscSIMS instrument, and Nick Fylstra for assistance with the Berkeley Geochronology Center Neptune ICP-MS. Two anonymous reviewers provided comments and suggestions that improved this paper. Funding was provided by NSF EAR Grants 1329568 (to E.J.O. and R.A.), 0207963 (to W.D.S. and R.A.), and 0207490 (to W.D.S. and R.A.). WiscSIMS is partly supported by NSF Grants EAR03-19230, EAR10-53466, and EAR13-55590. W.D.S. and J.M.H. secured funding from the University of Melbourne Collaborative Research Grant Scheme (International) to conduct the U-series work at the University of Melbourne. I.J.O. was also supported by NSF Grant AGS-1231155.