40Ar/39 Ar isotopic ages of Qitianling granite and their geologic implications.

Autor: Liu, Yimao, Xu, Jifeng, Dai, Tongmo, Li, Xianhua, Deng, Xiguang, Wang, Qiang
Zdroj: Science in China. Series D: Earth Sciences; Jan2003 Supplement, Vol. 46, p50-59, 10p
Abstrakt: This paper has reported the first application of 40Ar/39 Ar dating to orthoclase from Qitianling granite. The resultant plateau ages yielded by three orthoclase specimens 2KL-17, 99LQ-2 and 2KL-31 (Note: The last one was taken from the part of granite which had been attributed to Cailing super-unit of the Indosinian Period by the former researchers) collected from the said granite are (139.57±2.79) Ma, (140.55±2.81) Ma and (144.91±2.90) Ma respectively. The above-mentioned ages represent the closed 40Ar/39 Ar age of the orthoclase. The consistency in age dating results, the similarity in geochemical characteristics and rock textures, and the NW-SE orientation of orthoclase phenocrysts almost throughout the granite, provide evidence for the intimate relationship between the Furong super-unit and the Cailing super-unit that form the main part of the granite, suggesting that they are products of comagmatic conjugate differentiation during the Late Jurassic. This paper also makes a comparison between the Qitianling granite and the Qianlishan granite. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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