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A new paleoprecipitation proxy based on soil magnetic properties; implications for expanding paleoclimate reconstructions

Ethan G. Hyland, Nathan D. Sheldon, Rob Van der Voo, Catherine Badgley and Alexandra Abrajevitch
A new paleoprecipitation proxy based on soil magnetic properties; implications for expanding paleoclimate reconstructions
Geological Society of America Bulletin (February 2015) 127 (7-8): 975-981

Abstract

Description of precipitation patterns and changes in the hydrological cycle during periods of past global change is crucial for providing an understanding of terrestrial climate systems and for predicting impacts of future climate change such as shifting water availability. While a number of proxies and climofunctions exist for reconstructing paleoprecipitation using paleosols, all of the available tools for reconstructing paleoprecipitation are either limited to certain precipitation ranges (effective only for low-precipitation regimes; e.g., depth to Bk, chemical index of alteration [CIA-K]), or are relevant only to a limited range of paleosols (single-pedotype relationships; e.g., calcium-magnesium index [CALMAG]). Here, we measure the acquisition of isothermal remanent magnetization in B horizons of modern soils to quantify the ratio of pedogenic magnetic minerals goethite and hematite, and we use the relationship between these soil magnetic properties and measured climatic variables at each soil site to derive a new quantitative proxy for precipitation. By compiling both literature-derived and measured goethite-hematite (G/H) ratios and mean annual precipitation estimates for a global suite of modern soils (n=70), we describe a strong linear relationship (R (super 2) =0.96) between the G/H ratios of soil B horizons and mean annual precipitation that can be used to estimate paleoprecipitation values for a wide range of climatic regimes (100-3300 mm yr (super -1) ) and soil types (Inceptisols, Alfisols, Ultisols, Oxisols, Mollisols, Aridisols, Spodosols). We tested the new climofunction using paleosols from the early Eocene of Wyoming, which show that estimates based on G/H ratios compare favorably to and expand upon previously published estimates based on paleosol data.


ISSN: 0016-7606
EISSN: 1943-2674
Coden: BUGMAF
Serial Title: Geological Society of America Bulletin
Serial Volume: 127
Serial Issue: 7-8
Title: A new paleoprecipitation proxy based on soil magnetic properties; implications for expanding paleoclimate reconstructions
Affiliation: University of Michigan, Department of Earth and Environmental Sciences, Ann Arbor, MI, United States
Pages: 975-981
Published: 20150203
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 51
Accession Number: 2015-017360
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2015068
Illustration Description: illus. incl. sketch map
N41°00'00" - N45°00'00", W111°04'60" - W104°04'60"
Secondary Affiliation: Russian Academy of Sciences, Institute of Tectonics and Geophysics, RUS, Russian Federation
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, 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: 201509
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