气候变化领域集成服务门户(CCPortal): Resolving the argument about volcanic bedrock under the West Antarctic Ice Sheet and implications for ice sheet stability and sea level change

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DOI	10.1016/j.epsl.2021.117035
	Resolving the argument about volcanic bedrock under the West Antarctic Ice Sheet and implications for ice sheet stability and sea level change
	Andrews J.T.; LeMasurier W.
发表日期	2021
ISSN	0012821X
卷号	568
英文摘要	We provide a test for recent arguments that the West Antarctic Ice Sheet (WAIS) is underlain by an extensive outcrop of volcanic rock (mainly basalt) by examining the non-clay and clay mineral composition of sediments collected in front of and under the Ross Ice Shelf. If the proposed large volume were present, then we posit that glacial erosion and transport would deliver sediments to the Ross Sea enriched in minerals diagnostic of alkaline basalt, namely olivine, pyroxene, and plagioclase, and no quartz. Using quantitative X-ray diffraction analysis, we determine the weight percent of minerals in West Antarctic alkaline basalt, dolerite, gneiss, and granite bedrock, and compare these with a suite of 49 surface and near-surface sediment samples from a 1400 km west to east transect across the Ross Sea. Fifty percent of the samples had quartz percentage values >25% and had very small wt percentages of diagnostic basalt minerals. A sediment unmixing algorithm, with basalt, dolerite, gneiss and granite bedrock, end members, showed that the sediment contained virtually no basalt, was dominated by granite compositions, but did show some samples with an admixture of material derived from the Ferrar dolerite, which crops out extensively in the Transantarctic Mountains. Indicators of possible late Cenozoic volcanic bedrock – pyroxene, forsterite, and smectite weight percentages – decrease from west to east across the Ross Sea opposite to the trend of the quartz weight percent. Our study provides no support for the presence of extensive basalt outcrop under the WAIS, hence indicates that any changes in ice stream stability will not be influenced by basal heat regime. © 2021 Elsevier B.V.
关键词	Antarctic bedrock Cenozoic volcanics glacial erosion Ross Sea mineral composition sediment unmixing
英文关键词	Erosion; Glacial geology; Glaciers; Granite; Ice; Quartz; Sea level; Sediments; Silicate minerals; Volcanoes; X ray powder diffraction; Alkalines; Antarctic bedrock; Cenozoic volcanic; Glacial erosion; Ross Sea; Ross sea mineral composition; Sediment unmixing; Volcanics; Weight percent; West antarctic ice sheets; Basalt; bedrock; Cenozoic; glacial erosion; ice sheet; paleoceanography; paleoenvironment; sea level change; stability analysis; volcanic rock; Antarctic Ice Sheet; Antarctica; Ross Sea; Southern Ocean; West Antarctic Ice Sheet; West Antarctica
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203021
作者单位	Department of Geological Sciences, INSTAAR, University of Colorado, Boulder, CO 80303, United States; INSTAAR, University of Colorado, Boulder, CO 80303, United States
推荐引用方式 GB/T 7714	Andrews J.T.,LeMasurier W.. Resolving the argument about volcanic bedrock under the West Antarctic Ice Sheet and implications for ice sheet stability and sea level change[J],2021,568.
APA	Andrews J.T.,&LeMasurier W..(2021).Resolving the argument about volcanic bedrock under the West Antarctic Ice Sheet and implications for ice sheet stability and sea level change.Earth and Planetary Science Letters,568.
MLA	Andrews J.T.,et al."Resolving the argument about volcanic bedrock under the West Antarctic Ice Sheet and implications for ice sheet stability and sea level change".Earth and Planetary Science Letters 568(2021).