气候变化领域集成服务门户(CCPortal): Age and geochemistry of western Hoh-Xil-Songpan-Ganzi granitoids, northern Tibet: Implications for the Mesozoic closure of the Paleo-Tethys ocean

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DOI	10.1016/j.lithos.2013.12.019
	Age and geochemistry of western Hoh-Xil-Songpan-Ganzi granitoids, northern Tibet: Implications for the Mesozoic closure of the Paleo-Tethys ocean
	Zhang, Li-Yun; Ding, Lin; Pullen, Alex; Xu, Qiang; Liu, De-Liang; Cai, Fu-Long; Yue, Ya-Hui; Lai, Qing-Zhou; Shi, Ren-Deng; Ducea, Mihai N.; Kapp, Paul; Chapman, Alan
通讯作者	Zhang, LY (通讯作者)
发表日期	2014
ISSN	0024-4937
EISSN	1872-6143
起始页码	328
结束页码	348
卷号	190
英文摘要	A geologic investigation was undertaken in the Hoh-Xil-Songpan-Ganzi (HXSG) complex, northern Tibet in order to better understand magma genesis and evolution during the late stages of Paleo-Tethys ocean closure. The HXSG complex is composed of vast accumulations of Middle-Upper Triassic marine gravity flow deposits that were extensively intruded by igneous rocks. These early Mesozoic rocks exposed in this area record a rich history of accretionary tectonics during the amalgamation of the Tibetan Plateau terranes. Eight plutons sampled from the western HXSG complex yield zircon U-Pb ages that range from 225 to 193 Ma. Muscovite Ar-40/Ar-39 ages for the Hudongliang and Zhuonai Lake plutons yield ages of 210.7 +/- 2.5 Ma and 212.7 +/- 2.5 Ma, respectively. These plutonic rocks can be subdivided into two geochemically distinct groups. Group 1 (221-212 Ma: Dapeng Lake, Changhong Lake and Heishibei Lake plutons) is composed of high-K calc-alkaline rocks that have strongly fractionated REE patterns with high (La/Yb)(N) ratios (91-18) and generally lack Eu anomalies (Eu/Eu = 1.02-0.68). Rocks in Group 1 display pronounced negative Nb-Ta and Ti anomalies on primitive mantle-normalized spidergrams. Group 1 rocks exhibit high Sr (782-240 ppm) and low Y (6.3-16.0 ppm) contents with high Sr/Y ratios (84-20). Based on Sr-Nd-Hf isotopic data (Sr-87/Sr-86(i) = 0.7079-0.7090, epsilon Nd(t) = -7.7--4.7, epsilon Hf(t) = -5.7--0.8) and low MgO contents (MgO = 1.10-2.18%), Group 1 rocks are geochemically similar to adakitic rocks and were probably derived from partial melting of the downgoing Paleo-Tethys oceanic slab and overlying marine sediments. Group 2 plutons (225-193 Ma: Daheishan, Yunwuling, Zhuonai Lake, Malanshan and Hudongliang plutons) display lower P2O5 with increasing SiO2 and are medium-K to high-K I-type calcalkaline bodies with low Sr (14-549 ppm) and high Y (223-10.5 ppm) contents. Group 2 rocks have variable fractionated REE patterns ((La/Yb)N = 3-38) and negative Eu anomalies (Eu/Eu = 0.02-0.86). Together with Sr-Nd-Hf isotopes (Sr-87/Sr-86(i) = 0.7072-0.7143, epsilon Nd(t) = -6.6--2.0, epsilon Hf(t) = -0.6-+ 3.0), Group 2 rocks are most likely formed by partial melting of the juvenile crustal sources. Collectively, these data suggest that the Hoh-Xil turbidites were underlain by more continental arc crust than previously thought We propose that rollback of the subducting Paleo-Tethys oceanic slab led to partial melting of overlying continental arc fragments which developed beneath the HXSG gravity flow deposits. (C) 2013 Elsevier B.V. All rights reserved.
关键词	GARZE FOLD BELT ADAKITIC MAGMATISM ASSOCIATION U-PB ZIRCON A-TYPE GRANITE TECTONIC EVOLUTION SOUTH CHINA SW CHINA CONTINENTAL-CRUST SICHUAN PROVINCE VOLCANIC-ROCKS
英文关键词	Hoh-Xil-Songpan-Ganzi; Tibet; Granitoids; Paleo-Tethys; Rollback
语种	英语
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS类目	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:000333782300021
来源期刊	LITHOS
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/258383
推荐引用方式 GB/T 7714	Zhang, Li-Yun,Ding, Lin,Pullen, Alex,et al. Age and geochemistry of western Hoh-Xil-Songpan-Ganzi granitoids, northern Tibet: Implications for the Mesozoic closure of the Paleo-Tethys ocean[J]. 中国科学院青藏高原研究所,2014,190.
APA	Zhang, Li-Yun.,Ding, Lin.,Pullen, Alex.,Xu, Qiang.,Liu, De-Liang.,...&Chapman, Alan.(2014).Age and geochemistry of western Hoh-Xil-Songpan-Ganzi granitoids, northern Tibet: Implications for the Mesozoic closure of the Paleo-Tethys ocean.LITHOS,190.
MLA	Zhang, Li-Yun,et al."Age and geochemistry of western Hoh-Xil-Songpan-Ganzi granitoids, northern Tibet: Implications for the Mesozoic closure of the Paleo-Tethys ocean".LITHOS 190(2014).