Late Paleozoic tectono-metamorphic evolution of the Altai segment of the Central Asian Orogenic Belt: Constraints from metamorphic P-T Pseudosection and zircon U-Pb dating of ultra-high-temperature granulite

doi:10.1016/j.lithos.2014.05.022

	Late Paleozoic tectono-metamorphic evolution of the Altai segment of the Central Asian Orogenic Belt: Constraints from metamorphic P-T Pseudosection and zircon U-Pb dating of ultra-high-temperature granulite
	Li, Zilong 1; Yang, Xiaoqiang 1; Li, Yinqi 1; Santosh, M.2; Chen, Hanlin 1; Xiao, Wenjiao 3
刊名	LITHOS
	2014-09-01
卷号	204 页码:83-96
关键词	Ultra-high-temperature granulite P-T pseudosection Zircon U-Pb geochronology Late Paleozoic Altai orogenic belt
ISSN号	0024-4937
DOI	10.1016/j.lithos.2014.05.022
文献子类	Article
英文摘要	Ultra-high-temperature (UHT) granulite-facies rocks offer important constraints on crustal evolution processes and tectonic history of orogens. UHT granulites are generally rare in Phanerozoic orogens. In this study, we investigate the late Paleozoic pelitic UHT granulites from Altai in the western segment of the Central Asian Orogenic Belt (CAOB). The diagnostic minerals in these rocks include high alumina orthopyroxene (Al2O3 up to 9.76 wt.%, and y(opx) = Al-VI in orthopyroxene up to 0.21) coexisting with sillimanite and quartz, and low Zn spinel (ZnO = 1.85-2.50 wt.%) overgrowth with quartz. Cordierite corona separates sillimanite from orthopyroxene. The high alumina orthopyroxene is replaced by symplectites of low-alumina orthopyroxene (similar to 5.80 wt.% Al2O3) and cordierite. These textural observations are consistent with a significant decompression following the peak UHT metamorphism. Phase equilibrium modeling using pseudosections and the y(opx) isopleths indicate an anti-clockwise P-T path for the exhumation of the Altai orogenic belt. The pre-peak assemblage of spinel + quartz in garnet is stable at high- to ultra-high-temperature and low-pressure conditions (P <5.8 kbar at T similar to 900 degrees C). The peak P-T values recorded by high aluminium orthopyroxene is >940 degrees C and 7.8 to 10 kbar. Subsequent near-isothermal decompression occurred at 890 to 940 degrees C and 5 to 6 kbar. The final-stage cooling is recorded at 750 and 800 degrees C and 4 to 5 kbar accompanied by a decrease in the y(opx) values (0.11-0.12). In the UHT granulite, zircon grains are commonly enclosed within cordierite. The overgrowth rims of the zircon grains yield a weighted mean Pb-206/U-238 age of 277 +/- 2 Ma using LA-ICP-MS zircon dating, which is interpreted to mark the timing of decompression and cooling. We propose that the anti-clockwise P-T path of the UHT granulite in the Altai orogenic belt could be related to an extensional event related to the sinistral strike-slip along the Irtish tectonic belt after the subduction and slab detachment during the convergence of the Kazakhstan-Junggar plate and the Siberian plate. (C) 2014 Elsevier B.V. All rights reserved.
WOS关键词	MINERAL EQUILIBRIA CALCULATIONS ; SOR RONDANE MOUNTAINS ; CRUSTAL METAMORPHISM ; NORTHWESTERN CHINA ; SYSTEM K2O-FEO-MGO-AL2O3-SIO2-H2O-TIO2-FE2O3 ; EAST ANTARCTICA ; CENTRAL ALPS ; SUTURE ZONE ; NW CHINA ; ROCKS
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000342260400009
资助机构	National Basic Research Program of China (973 Program)(2011CB808902) ; National Basic Research Program of China (973 Program)(2011CB808902) ; National Natural Science Foundation of China(40972045 ; National Natural Science Foundation of China(40972045 ; Research Fund for the Doctoral Program of Higher Education of China(20110101110001) ; Research Fund for the Doctoral Program of Higher Education of China(20110101110001) ; 41072048) ; 41072048) ; National Basic Research Program of China (973 Program)(2011CB808902) ; National Basic Research Program of China (973 Program)(2011CB808902) ; National Natural Science Foundation of China(40972045 ; National Natural Science Foundation of China(40972045 ; Research Fund for the Doctoral Program of Higher Education of China(20110101110001) ; Research Fund for the Doctoral Program of Higher Education of China(20110101110001) ; 41072048) ; 41072048) ; National Basic Research Program of China (973 Program)(2011CB808902) ; National Basic Research Program of China (973 Program)(2011CB808902) ; National Natural Science Foundation of China(40972045 ; National Natural Science Foundation of China(40972045 ; Research Fund for the Doctoral Program of Higher Education of China(20110101110001) ; Research Fund for the Doctoral Program of Higher Education of China(20110101110001) ; 41072048) ; 41072048) ; National Basic Research Program of China (973 Program)(2011CB808902) ; National Basic Research Program of China (973 Program)(2011CB808902) ; National Natural Science Foundation of China(40972045 ; National Natural Science Foundation of China(40972045 ; Research Fund for the Doctoral Program of Higher Education of China(20110101110001) ; Research Fund for the Doctoral Program of Higher Education of China(20110101110001) ; 41072048) ; 41072048)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/85524]
专题	中国科学院地质与地球物理研究所
通讯作者	Li, Zilong
作者单位	1.Zhejiang Univ, Dept Earth Sci, Hangzhou 310027, Peoples R China 2.China Univ Geosci, Sch Earth Sci & Resources, Beijing 100083, Peoples R China 3.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Li, Zilong,Yang, Xiaoqiang,Li, Yinqi,et al. Late Paleozoic tectono-metamorphic evolution of the Altai segment of the Central Asian Orogenic Belt: Constraints from metamorphic P-T Pseudosection and zircon U-Pb dating of ultra-high-temperature granulite[J]. LITHOS,2014,204:83-96.
APA	Li, Zilong,Yang, Xiaoqiang,Li, Yinqi,Santosh, M.,Chen, Hanlin,&Xiao, Wenjiao.(2014).Late Paleozoic tectono-metamorphic evolution of the Altai segment of the Central Asian Orogenic Belt: Constraints from metamorphic P-T Pseudosection and zircon U-Pb dating of ultra-high-temperature granulite.LITHOS,204,83-96.
MLA	Li, Zilong,et al."Late Paleozoic tectono-metamorphic evolution of the Altai segment of the Central Asian Orogenic Belt: Constraints from metamorphic P-T Pseudosection and zircon U-Pb dating of ultra-high-temperature granulite".LITHOS 204(2014):83-96.