Geochemistry and geochronology of S-type granites and their coeval MP/HT   meta-sedimentary rocks in Chinese Southwest Tianshan and their tectonic   implications

doi:10.1016/j.jseaes.2015.04.020

CORC > 北京大学 > 地球与空间科学学院

	Geochemistry and geochronology of S-type granites and their coeval MP/HT meta-sedimentary rocks in Chinese Southwest Tianshan and their tectonic implications
	Gou, Long-Long ; Zhang, Li-Fei ; Lu, Zeng ; Shen, Ting-Ting
刊名	JOURNAL OF ASIAN EARTH SCIENCES
	2015
关键词	S-type granites MP/HT metamorphism Anatexis Paired metamorphic belt Chinese Southwest Tianshan ZIRCON U-PB ULTRAHIGH-PRESSURE METAMORPHISM ASIAN OROGENIC BELT SOUTHERN TIEN-SHAN LACHLAN FOLD BELT WESTERN TIANSHAN NW CHINA CONTINENTAL-CRUST NORTHWESTERN CHINA VOLCANIC-ROCKS
DOI	10.1016/j.jseaes.2015.04.020
英文摘要	This paper presents whole-rock geochemical data, in-situ zircon U-Pb ages and Hf isotopic composition, monazite U-Th-Pb age and pseudosection modeling result, in order to reveal the genetic relationship between S-type granites and meta-sedimentary rocks in the Central Tianshan and their tectonic implications for the South Tianshan Orogenic Belt. The S-type granites have the LA-ICP-MS zircon U-Pb ages of 275 +/- 3 Ma, 266 +/- 13 Ma and 278 +/- 3 Ma, interpreted as the crystallization ages. They have high contents of SiO2 (72.41-83.24 wt.%) and K2O (2.96-8.47 wt.%) and low contents of Fe(2)O(3)t (0.61-2.19 wt.%), MgO (0-0.49 wt.%) and CaO (0.61-1.51 wt.%), with A/CNK ratios of 1.14-1.35. The SHRIMP zircon U-Pb dating for the metapelite yields a weighted mean Pb-206/U-238 age of 393 +/- 7 Ma and a significantly younger apparent (206)pb/U-238 age of 267 6 Ma, whereas the EMP monazite dating gives three age groups, including 482 +/- 19 Ma, 366 +/- 10-376 +/- 13 Ma, and 282 +/- 17 Ma. Two metamorphic events are identified, one is the regional anatexis event at ca. 393 Ma based on the recent published result, which may be related to the arc magmatism, and the other is an anatexis event at ca. 280 Ma in the post-collisional setting. Pseudosection modeling shows that the meta-sedimentary rocks have experienced the anatexis under a P-T condition of 7.21 kbar and 728 degrees C, consistent with medium-pressure facies series. Thus, the meta-sedimentary rocks are inferred to have been buried to the depths of middle-to-lower crust through the crustal thickening during the continental collision at ca. 320-300 Ma, and then these rocks experienced the anatexis to form the S-type granites in the post-collisional setting with the heat possibly provided by the upwelling of asthenosphere and crustal thinning. (C) 2015 Elsevier Ltd. All rights reserved.; Major State Basic Research Development Program [2015CB856105]; National Natural Science Foundation of China [41330210, 410090371, 41302036]; Foundation of State Key Laboratory of Continental Dynamics [BJ08133-12]; Natural Science Foundation of Northwest University, China [12NW29]; Start-up Research Foundation of Northwest University, China [PR12104]; SCI(E); ARTICLE; Lfzhang@pku.edu.cn; 151-171; 107
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/417871]
专题	地球与空间科学学院
推荐引用方式 GB/T 7714	Gou, Long-Long,Zhang, Li-Fei,Lu, Zeng,et al. Geochemistry and geochronology of S-type granites and their coeval MP/HT meta-sedimentary rocks in Chinese Southwest Tianshan and their tectonic implications[J]. JOURNAL OF ASIAN EARTH SCIENCES,2015.
APA	Gou, Long-Long,Zhang, Li-Fei,Lu, Zeng,&Shen, Ting-Ting.(2015).Geochemistry and geochronology of S-type granites and their coeval MP/HT meta-sedimentary rocks in Chinese Southwest Tianshan and their tectonic implications.JOURNAL OF ASIAN EARTH SCIENCES.
MLA	Gou, Long-Long,et al."Geochemistry and geochronology of S-type granites and their coeval MP/HT meta-sedimentary rocks in Chinese Southwest Tianshan and their tectonic implications".JOURNAL OF ASIAN EARTH SCIENCES (2015).