首页|Loess-paleosol carbonate clumped isotope record of late Pleistocene-Holocene climate change in the Palouse region, Washington State, USA

Loess-paleosol carbonate clumped isotope record of late Pleistocene-Holocene climate change in the Palouse region, Washington State, USA

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  • NSTL
  • Cambridge Univ Press
The Channeled Scabland-Palouse region of the Pacific Northwest (PNW) of the United States preserves geomorphic and pedosedimentary records that inform understanding of late Pleistocene-Holocene paleoclimate change in a region proximal to the last glacial period Cordilleran Ice Sheet. We present a clumped (Delta(47)) and conventional (delta O-18, delta C-13) isotopic study of Palouse loess-paleosol carbonates in combination with carbonate radiocarbon (C-14) dating to provide new measures of regional late-last glacial (similar to 31-20 cal ka BP) and Holocene soil conditions. Average clumped isotope temperatures (T(Delta(47))) for last glacial Palouse loess-paleosol carbonates (9 +/- 4 degrees C) are significantly lower than those for Holocene-aged carbonates (T(Delta(47)) = 18 +/- 2 degrees C) in study sections. Calculated soil water delta O-18(VSMOW) values (-16 +/- 2 parts per thousand) for last glacial carbonates are also offset relative to those for Holocene-aged samples (-11 +/- 1 parts per thousand), whereas calculated soil CO2 delta C-13(VPDB) values are similar for the Holocene (-16.9 +/- 0.2 parts per thousand) and late-last glacial (-16.7 +/- 1.1 parts per thousand) periods. Together, these paleoclimate metrics indicate late-last glacial conditions of pedogenic carbonate formation in the C-3 grassland soils of the Palouse were measurably colder (9 +/- 5 degrees C) than during the Holocene and potentially reflect a more arid last glacial paleoclimate across the Palouse, findings in agreement with previous proxy studies and climate model simulations for the region.

LoessPaleosolPalouseClumped isotopePedogenic carbonateLGMPaleoclimate

Lechler, Alex R.、Huntington, Katharine W.、Breecker, Daniel O.、Sweeney, Mark R.、Schauer, Andrew J.

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Pacific Lutheran Univ, Dept Geosci, Rieke 158, Tacoma, WA 98447 USA

Univ Washington, Dept Earth & Space Sci, Seattle, WA 98195 USA

Univ Texas Austin, Jackson Sch Geosci, Dept Geol Sci, Austin, TX 78712 USA

Univ South Dakota, Dept Sustainabil & Environm, Vermillion, SD 57069 USA

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2018

10.1017/qua.2018.47

Quaternary Research

Quaternary Research

ISTP
ISSN：0033-5894
年,卷(期)：2018.90(2)
  • 11
  • 91