Geochemistry and geochronology of the Precambrian high-grade metamorphic complex in the Southern Central Tianshan ophiolitic m lange, NW China

doi:10.1016/j.precamres.2014.08.017

	Geochemistry and geochronology of the Precambrian high-grade metamorphic complex in the Southern Central Tianshan ophiolitic m lange, NW China
	Wang, Xin-Shui 1,2; Gao, Jun 1; Klemd, Reiner 3; Jiang, Tuo 1,2; Li, Ji-Lei 1; Zhang, Xi 4; Tan, Zhou 1,2; Li, Le 1,2; Zhu, Zhixin 5
刊名	PRECAMBRIAN RESEARCH
	2014-11-01
卷号	254 页码:129-148
关键词	Central Tianshan Wuwamen Complex Supercontinent Tarim Craton Tectonic evolution
ISSN号	0301-9268
DOI	10.1016/j.precamres.2014.08.017
文献子类	Article
英文摘要	The Central Tianshan Arc Terrane is one of the major constituents of the Tianshan orogen in the southwestern Altaids. Thus its Precambrian evolution is important for unravelling the geodynamic and continental evolution of the Altaids. Biotite-plagioclase-hornblende orthogneisses intruded by leucogranite dykes are exposed as exotic blocks within the Southern Central Tianshan ophiolitic m lange. Zircon U-Pb age dating of one orthogneiss sample yields an upper intercept age of 2466 51 Ma and a weighted mean O-2 7pb/206pb age of 1812 19 Ma around the lower intercept. These ages are interpreted as protolith crystallization age and subsequent metamorphic overprint age, respectively. The orthogneisses have moderate SiO2 contents, high MgO and Na2O contents, high Sr/Y ratios (32-43) and moderately fractionated REE patterns (112/Y1AN = 7.59-13.64) with negligible Eu anomalies, enriched Sr contents and pronounced negative Th-U, Nb-Ta, Zr-Hf and Ti anomalies resembling high-SiO2 TTGs derived from subducted basaltic slab-melts. Positive stif(t) values (+3.4 to +9.2) and low (176Hf/177H01 ratios (0.281304-0.281469) with Neoarchaean to early Paleoproterozoic single-stage Hf model ages (Tm,41= 2431-2652 Ma) suggest that the orthogneisses probably originated from partial melting of juvenile subducted oceanic crust. The orthogneisses were subsequently also affected by collisional orogenic events associated with the assembly of the supercontinent Columbia. In contrast, the zircon U-Pb age of 785 15 Ma obtained for the intrusive leucogranite dykes is consistent with the timing of rifting events associated with the breakup of Rodinia. The leucogranites have a high-Al trondhjemitic composition characterized by extremely low MgO and 120 contents as well as high SiO2, Al2O3 and Na2O contents, dramatically low EREE abundances and REE patterns with moderate LREE enrichments ([La/Yb](N) =3.55-8.4) and pronounced positive Eu anomalies (Eu/Eu* = 1.29-2.61). The high zircon initial Hf compositions (0.281670-0.281841) and negative sHf(t) values (-21.7 to -15.4), in conjunction with high whole-rock initial 87Sr/86Sr ratios (0.70737-0.70751) and negative sNd(t) values (-4.7 to -5.1) suggest that the leucogranite resulted from reworking of ancient lower crust. Based on the presented data we conclude that the Central Tianshan Arc Terrane has undergone three tectonothermal events, namely -2.5 Ga continental crustal growth, -1.8 Ga collision related to the Columbia assembly and -785 Ma crustal reworking due to the Rodinia breakup. The Central Tianshan Arc Terrane, which experienced the same tectonic events as the Tarim Craton during the Precambrian, is considered to be a micro-Precambrian block that separated from the Tarim Craton during the Rodinia breakup. (C) 2014 Elsevier B.V. All rights reserved.
WOS关键词	ZIRCON U-PB ; PALEOZOIC TECTONIC EVOLUTION ; NORTHEASTERN TARIM BLOCK ; ASIAN OROGENIC BELT ; TRONDHJEMITE-GRANODIORITE TTG ; HF-ISOTOPE EVIDENCE ; A-TYPE GRANITES ; CONTINENTAL-CRUST ; VOLCANIC-ROCKS ; NORTHWESTERN CHINA
WOS研究方向	Geology
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000343786400008
资助机构	National Natural Science Foundation of China(41390445 ; National Natural Science Foundation of China(41390445 ; China Geological Survey(1212010911070) ; China Geological Survey(1212010911070) ; DFG(KL 692/17-3) ; DFG(KL 692/17-3) ; 41025008) ; 41025008) ; National Natural Science Foundation of China(41390445 ; National Natural Science Foundation of China(41390445 ; China Geological Survey(1212010911070) ; China Geological Survey(1212010911070) ; DFG(KL 692/17-3) ; DFG(KL 692/17-3) ; 41025008) ; 41025008) ; National Natural Science Foundation of China(41390445 ; National Natural Science Foundation of China(41390445 ; China Geological Survey(1212010911070) ; China Geological Survey(1212010911070) ; DFG(KL 692/17-3) ; DFG(KL 692/17-3) ; 41025008) ; 41025008) ; National Natural Science Foundation of China(41390445 ; National Natural Science Foundation of China(41390445 ; China Geological Survey(1212010911070) ; China Geological Survey(1212010911070) ; DFG(KL 692/17-3) ; DFG(KL 692/17-3) ; 41025008) ; 41025008)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/86184]
专题	中国科学院地质与地球物理研究所
通讯作者	Gao, Jun
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Mineral Resources, Beijing 100029, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 3.Univ Erlangen Nurnberg, GeoZentrum Nordbayem, D-91054 Erlangen, Germany 4.China Minmet Corp, Beijing 100010, Peoples R China 5.Geol Res Acad Xinjiang, Urumqi 830011, Peoples R China
推荐引用方式 GB/T 7714	Wang, Xin-Shui,Gao, Jun,Klemd, Reiner,et al. Geochemistry and geochronology of the Precambrian high-grade metamorphic complex in the Southern Central Tianshan ophiolitic m lange, NW China[J]. PRECAMBRIAN RESEARCH,2014,254:129-148.
APA	Wang, Xin-Shui.,Gao, Jun.,Klemd, Reiner.,Jiang, Tuo.,Li, Ji-Lei.,...&Zhu, Zhixin.(2014).Geochemistry and geochronology of the Precambrian high-grade metamorphic complex in the Southern Central Tianshan ophiolitic m lange, NW China.PRECAMBRIAN RESEARCH,254,129-148.
MLA	Wang, Xin-Shui,et al."Geochemistry and geochronology of the Precambrian high-grade metamorphic complex in the Southern Central Tianshan ophiolitic m lange, NW China".PRECAMBRIAN RESEARCH 254(2014):129-148.