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DOI	10.1016/j.gca.2019.07.031
	Silicate weathering in antarctic ice-rich permafrost: Insights using magnesium isotopes
	Cuozzo, Nicolas 1; Sletten, Ronald S.1; Hu, Yan 1; Liu, Lu 1; Teng, Fang-Zhen 1; Hagedorn, Birgit 2
通讯作者	Cuozzo, Nicolas
来源期刊	GEOCHIMICA ET COSMOCHIMICA ACTA
ISSN	0016-7037
EISSN	1872-9533
出版年	2020
卷号	278 页码:244-260
英文摘要	This study reports that substantial chemical weathering occurs at subzero temperatures in ice-and-salt-rich permafrost in the McMurdo Dry Valleys, Antarctica. Chemical weathering is documented in a 30.0-m core collected in Beacon Valley by measuring the ionic composition, pH, and Mg isotopes of water extracted from thawed ice-rich sediment. Evidence of rock weathering is revealed by coinciding increases in the Mg isotopic composition and pH values. The primary factor that controls weathering is the salt content that leads to unfrozen brine; this is most apparent in the upper 7.0 m where salt content is high, temperatures rise above -21 degrees C and modeled unfrozen water reaches up to 4.0% of ice-content. In the upper 7.0 m, up to 60% of soluble Mg in the thawed permafrost ice is sourced from Ferrar Dolerite (delta Mg-26 = -0.22 +/- 0.07%) weathering, resulting in delta Mg-26 values ranging from of -0.82 +/- 0.05 parts per thousand to -0.64 +/- 0.05 parts per thousand. Below 7.0 m, temperatures remain below -21 degrees C, unfrozen water is less than 2.0% of ice-content, and on average, 5% of soluble Mg is sourced from dolerite weathering with delta Mg-26 values ranging from -1.05 +/- 0.05 parts per thousand to -0.76 +/- 0.05 parts per thousand. Regions of the core that are modeled to have no unfrozen water show little or no evidence of chemical weathering and relatively constant delta Mg-26 values close to Taylor Glacier and Beacon Valley snowfall values (-0.93 +/- 0.06 parts per thousand). This study demonstrates that significant chemical weathering occurs at subzero temperatures in permafrost where liquid brines form. (C) 2019 Elsevier Ltd. All rights reserved.
英文关键词	Polar deserts McMurdo Dry Valleys Beacon Valley Permafrost Unfrozen water Brine Mars analog
类型	Article
语种	英语
国家	USA
收录类别	SCI-E
WOS记录号	WOS:000536445700002
WOS关键词	MCMURDO DRY VALLEYS ; SOUTHERN-VICTORIA-LAND ; BEACON-VALLEY ; SOIL SOLUTIONS ; TAYLOR VALLEY ; MG ISOTOPES ; FRACTIONATION ; ANALOG ; GEOCHEMISTRY ; STRONTIUM
WOS类目	Geochemistry & Geophysics
WOS研究方向	Geochemistry & Geophysics
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/319213
作者单位	1.Univ Washington, Dept Earth & Space Sci, Seattle, WA 98195 USA; 2.Sustainable Earth Res LLC, Anchorage, AK 99508 USA
推荐引用方式 GB/T 7714	Cuozzo, Nicolas,Sletten, Ronald S.,Hu, Yan,et al. Silicate weathering in antarctic ice-rich permafrost: Insights using magnesium isotopes[J],2020,278:244-260.
APA	Cuozzo, Nicolas,Sletten, Ronald S.,Hu, Yan,Liu, Lu,Teng, Fang-Zhen,&Hagedorn, Birgit.(2020).Silicate weathering in antarctic ice-rich permafrost: Insights using magnesium isotopes.GEOCHIMICA ET COSMOCHIMICA ACTA,278,244-260.
MLA	Cuozzo, Nicolas,et al."Silicate weathering in antarctic ice-rich permafrost: Insights using magnesium isotopes".GEOCHIMICA ET COSMOCHIMICA ACTA 278(2020):244-260.