A loess–paleosol record of climate and glacial history over the past two glacial–interglacial cycles (~150 ka), southern Jackson Hole, Wyoming

Authors

• Kenneth L. Pierce, U.S. Geological SurveyFollow
• Daniel R. Muhs, U.S. Geological SurveyFollow
• Maynard A. Fosberg, University of Idaho, Moscow
• Shannon A. Mahan, US Geological Survey
• Joseph G. Rosenbaum, US Geological Survey
• Joseph M. Licciardi, University of New Hampshire, Durham
• Milan J. Pavich, US Geological Survey

Document Type

Article

Date of this Version

2011

Citation

Quaternary Research 76 (2011) 119–141

doi:10.1016/j.yqres.2011.03.006

Comments

U.S. government work

Abstract

Loess accumulated on a Bull Lake outwash terrace of Marine Oxygen Isotope Stage 6 (MIS 6) age in southern Jackson Hole, Wyoming. The 9 m section displays eight intervals of loess deposition (Loess 1 to Loess 8, oldest), each followed by soil development. Our age-depth model is constrained by thermoluminescence, meteoric ¹⁰Be accumulation in soils, and cosmogenic ¹⁰Be surface exposure ages. We use particle size, geochemical, mineral-magnetic, and clay mineralogical data to interpret loess sources and pedogenesis. Deposition of MIS 6 loess was followed by a tripartite soil/thin loess complex (Soils 8, 7, and 6) apparently re!ecting the large climatic oscillations of MIS 5. Soil 8 (MIS 5e) shows the strongest development. Loess 5 accumulated during a glacial interval (~76–69 ka; MIS 4) followed by soil development under conditions wetter and probably colder than present. Deposition of thick Loess 3 (~43–51 ka, MIS 3) was followed by soil development comparable with that observed in Soil 1. Loess 1 (MIS 2) accumulated during the Pinedale glaciation and was followed by development of Soil 1 under a semiarid climate. This record of alternating loess deposition and soil development is compatible with the history of Yellowstone vegetation and the glacial !our record from the Sierra Nevada.