Geochemical constraints on the petrogenesis of the Proterozoic granitoid gneisses from the eastern segment of the Central Tianshan Tectonic Zone, northwestern China

doi:10.1017/S0016756806002688

	Geochemical constraints on the petrogenesis of the Proterozoic granitoid gneisses from the eastern segment of the Central Tianshan Tectonic Zone, northwestern China
	Li, Qiugen ; Liu, Shuwen ; Wang, Zongqi ; Yan, Quanren ; Guo, Zhaojie ; Zhang, Zhicheng ; Zheng, Haifei ; Jiang, Chunfa ; Wang, Tao ; Chu, Zhuyin
刊名	GEOLOGICAL MAGAZINE
	2007-03-01
卷号	144 期号:2 页码:305-317
关键词	Proterozoic granitoid gneisses geochemistry petrogenesis tectonic setting
ISSN号	0016-7568
DOI	10.1017/S0016756806002688
文献子类	Article
英文摘要	The Tianshan orogen is divided into the Northern, Central and Southern Tianshan tectonic zones by the northern and southern sutures on both sides of the Central Tianshan Tectonic Zone. The eastern segment of the Central Tianshan Tectonic Zone is characterized by the presence of numerous Precambrian metamorphic blocks and is unconformably overlain by Ordovician-Silurian and late Palaeozoic strata. The Precambrian Kumishi and Pargantag metamorphic blocks are the largest older blocks in the eastern segment of the Central Tianshan Tectonic Zone, consisting mainly of metamorphic granitoids and sedimentary rocks in greenschist to amphibolite facies. There are two major lithological assemblages of the metamorphic granitoids: (1) quartz dioritic gneisses, and (2) granodioritic-monzogranitic gneisses with a minor amount of tonalitic and syenogranitic gneisses in both the Kumishi and Pargantag blocks. The quartz dioritic gneisses are characterized by low Sr/Ce (< 5.3) and Sr/Y (< 28), relatively high Mg no. (51.0-57.0), K(2)O (2.65-4.04 wt %) contents and epsilon(Nd)(t) values (-2.37-5.84), and negative Nb and Zr-Hf anomalies, as well as relatively flat chondrite-normalized REE patterns with slightly negative Eu anomalies, suggesting that the quartz dioritic gneisses were derived from partial melting of a depleted mantle source enriched by fluids and sedimentary melts from the subducted slab. However, most of granitic gneiss samples display high K(2)O contents, low Al(2)O(3)/(FeO* + MgO + TiO(2)) values, and relatively flat chondrite-normalized REE patterns with intensively negative Eu anomalies. Integrated low epsilon(Nd)(t) values and older T(DM) model ages suggest that crustal materials played a significant role in the petrogenesis of these granitoid gneisses and that they were mainly derived from the partial melting of calc-alkaline mafic to intermediate rocks in the crust. Also, variations in geochemical features between the Kumishi-Gangou and Pargantag regions, such as Zr and Hf, may reflect geographic variability in the development of coeval granitic magmas. Tectonic discrimination for granitoid, using trace elements, together with Nd isotopic data, demonstrates that these granitoid gneisses in the eastern segment of the Central Tianshan Tectonic Zone formed in a continental margin arc during late Mesoproterozoic times.
WOS关键词	CENTRAL-ASIA ; CONTINENTAL GROWTH ; VOLCANIC-ROCKS ; COLLISIONAL TECTONICS ; METASEDIMENTARY ROCKS ; PALEOZOIC ACCRETION ; CRUSTAL GROWTH ; FUPING COMPLEX ; CALC-ALKALINE ; SHEAR ZONES
WOS研究方向	Geology
语种	英语
出版者	CAMBRIDGE UNIV PRESS
WOS记录号	WOS:000245612400007
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/68368]
专题	中国科学院地质与地球物理研究所
通讯作者	Liu, Shuwen
作者单位	1.Peking Univ, Sch Earth & Space Sci, Minist Educ, Key Lab Orogran Belts & Crustal Evolut, Beijing 100871, Peoples R China 2.Chinese Acad Geol Sci, Inst Geol, Beijing 100037, 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, Qiugen,Liu, Shuwen,Wang, Zongqi,et al. Geochemical constraints on the petrogenesis of the Proterozoic granitoid gneisses from the eastern segment of the Central Tianshan Tectonic Zone, northwestern China[J]. GEOLOGICAL MAGAZINE,2007,144(2):305-317.
APA	Li, Qiugen.,Liu, Shuwen.,Wang, Zongqi.,Yan, Quanren.,Guo, Zhaojie.,...&Chu, Zhuyin.(2007).Geochemical constraints on the petrogenesis of the Proterozoic granitoid gneisses from the eastern segment of the Central Tianshan Tectonic Zone, northwestern China.GEOLOGICAL MAGAZINE,144(2),305-317.
MLA	Li, Qiugen,et al."Geochemical constraints on the petrogenesis of the Proterozoic granitoid gneisses from the eastern segment of the Central Tianshan Tectonic Zone, northwestern China".GEOLOGICAL MAGAZINE 144.2(2007):305-317.