极地研究(英文版)2000，Vol.11Issue(2)：79-88,10.
Composition of plagioclases in volcanic rocks of King George Island, Antarctica with reference to the petrogenetic significance
Composition of plagioclases in volcanic rocks of King George Island, Antarctica with reference to the petrogenetic significance
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作者信息
- 1. Antarctic Research Center, Nanjing Institute of Geology and Mineral Resources, Nanjing 210016, China;Antarctic Research Center, Nanjing Institute of Geology and Mineral Resources, Nanjing 210016, China
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摘要
Abstract
Plagioclases occur mainly as phenocrysts in volcanic rocks of King George Island, South Shetland Islands, West Antarctica. In basaltic andesites and andesites of Keller Peninsula and Ullman Spur (Admiralty Bay), they are high structure state labradorite-andesines; and in high-A1 basalts and basaltic andesites of Barton and Weaver peninsulas (Maxwell Bay), they are high structure state bytownite-anorthites.∑REE, La/Yb ratios and δEu values of plagioclases from Admiralty Bay are higher than those from Maxwell Bay. All plagioclases have rather identical chondritenormalized transitional element distribution patterns, probably reflecting that crystal structure rather than composition of plagioclase controls their diversity. Compositions of plagioclases depend chiefly on those of their host rocks, compositional differences of plagioclases reveal that basaltic magmas in the Admiralty Bay area are more evolved than in the Maxwell Bay area.关键词
composition of plagioclases/volcanic rocks/King George Island/AntarcticaKey words
composition of plagioclases/volcanic rocks/King George Island/Antarctica分类
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..Composition of plagioclases in volcanic rocks of King George Island, Antarctica with reference to the petrogenetic significance[J].极地研究(英文版),2000,11(2):79-88,10.
