Geochemistry, age and tectonic significance of granitic rocks in north Altun, northwest China

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	Geochemistry, age and tectonic significance of granitic rocks in north Altun, northwest China
	Wu, CL (Wu, Cailai); Yang, JS (Yang, Jingsui); Robinson, PT (Robinson, Paul T.); Wooden, JL (Wooden, Joseph L.); Mazdab, FK (Mazdab, Frank K.); Gao, YH (Gao, Yunhong); Wu, SP (Wu, Suoping); Chen, QL (Chen, Qilong)
刊名	LITHOS
	2009
卷号	113 期号:3-4 页码:423-436
关键词	Granite Zircon SHRIMP U-Pb dating Bashikaogong Valley North Altun
ISSN号	0024-4937
英文摘要	Granitic rocks in the Altun terrane, NW China crop out in a 50-km-long, E-W-trending belt along the southern margin of the Bashikaogong Basin, north Altun. They intrude the north Altun subduction complex and are hosted in Precambrian sandstones, schists, mudstones and tuffs. Four lithologic types are recognized; (I) gray, very coarsely phyric granite, (II) red, fine- to medium-grained, aphyric granite, (III) gray, medium- to coarse-grained, moderately phyric granite and (IV) pink, medium- to coarse-grained, moderately phyric granite. All of the granites are peraluminous with normative corundum ranging from 0.8 to 3.9 wt.%. Silica contents vary between 65.1% and 75.7%, and total alkalis (Na(2)O+K(2)O) range from 7.5 to 9.0 wt.%, giving K(2)O/Na(2)O ratios of 1.1 to 2.7. Rittman indices vary from 1.8 to 2.8, with an average of 2.3. Total rare earth elements (Sigma REE) are between 89 and 335 ppm, and all samples show significant but variable negative Eu anomalies on chondrite-normalized REE patterns. On mantle-normalized trace element patterns all the granites have pronounced negative Ba, Nb, Sr, P and Ti anomalies. Zircons from the granites show slightly different SHRIMP U-Pb ages for the different lithologies; 474.3 +/- 6.8 Ma for type I granites, 446.6 +/- 5.2 Ma for type II, 434.5 +/- 3.8 Ma for type III, and 431.1 +/- 3.8 Ma for type IV. The geochemical and geological data indicate that these are S-type granites formed by partial melting of crustal materials during or shortly after collision of the Altun and Tarim continental blocks in the Paleozoic. The age and geochemistry of the north Altun granites suggest that they can be correlated with similar rocks in north Qilian on the opposite side of the Altun strike-slip fault. (C) 2009 Elsevier B. V. All rights reserved.
学科主题	火成岩岩石学
WOS关键词	U-PB AGES ; ALTYN-TAGH ; TIBETAN PLATEAU ; ZIRCON AGES ; EVOLUTION ; SUBDUCTION ; MAGMATISM ; MOUNTAINS ; MONAZITE ; BAVARIA
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000272787200005
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/39028]
专题	中国地质调查局
作者单位	Stanford Univ, Dept Earth & Environm Sci, Stanford, CA 94305 USA
推荐引用方式 GB/T 7714	Wu, CL ,Yang, JS ,Robinson, PT ,et al. Geochemistry, age and tectonic significance of granitic rocks in north Altun, northwest China[J]. LITHOS,2009,113(3-4):423-436.
APA	Wu, CL .,Yang, JS .,Robinson, PT .,Wooden, JL .,Mazdab, FK .,...&Chen, QL .(2009).Geochemistry, age and tectonic significance of granitic rocks in north Altun, northwest China.LITHOS,113(3-4),423-436.
MLA	Wu, CL ,et al."Geochemistry, age and tectonic significance of granitic rocks in north Altun, northwest China".LITHOS 113.3-4(2009):423-436.