气候变化领域集成服务门户(CCPortal): Tectonic and magmatic evolution of the Aqishan-Yamansu belt: A Paleozoic arc-related basin in the Eastern Tianshan (NW China)

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DOI	10.1130/B35749.1
	Tectonic and magmatic evolution of the Aqishan-Yamansu belt: A Paleozoic arc-related basin in the Eastern Tianshan (NW China)
	Zhang S.; Chen H.; Hollings P.; Zhao L.; Gong L.
发表日期	2021
ISSN	167606
起始页码	1320
结束页码	1344
卷号	133 期号:2021-05-06
英文摘要	The Aqishan-Yamansu belt in the Chinese Eastern Tianshan represents a Paleozoic arc-related basin generally accompanied by accretionary magmatism and Fe-Cu mineralization. To characterize the tectonic evolution of such an arc-related basin and related magmatism and metallogenesis, we present a systematic study of the geochronology, whole-rock geochemistry, and Sr-Nd isotopes of igneous rocks from the belt. New zircon U-Pb ages, in combination with published data, reveal three phases of igneous activity in the Aqishan-Yamansu belt: early Carboniferous felsic igneous rocks (ca. 350-330 Ma), late Carboniferous intermediate to felsic igneous rocks (ca. 320-305 Ma), and Permian quartz diorite and diorite porphyry dikes (ca. 280-265 Ma). The early Carboniferous felsic rocks are enriched in large ion lithophile elements (LILEs) and depleted in Nb, Ta, and Ti, showing arc-related magma affinities. Their positive εNd(Z) values (3.3-5.9) and corresponding depleted mantle model ages (TDM) of 0.83-0.61 Ga, as well as high MgO contents, Mg# values, and Nb/Ta ratios, suggest that they were derived from lower crust with involvement of mantle-derived magmas. The late Carboniferous intermediate igneous rocks show calc-alkaline affinities, exhibiting LILE enrichment and high field strength element (HFSE) depletion, with negative Nb and Ta anomalies. They have high MgO contents and Mg# values with positive εNd(t) values (3.9-7.9), and high Ba/La and Th/Yb ratios, implying a depleted mantle source metaso-matized by slab-derived fluids and sediment or sediment-derived melts. The late Carbon-iferous felsic igneous rocks are metalumi-nous to peraluminous with characteristics of medium-K calc-alkaline I-type granites. Given the positive £Nd(t) values (6.3-6.6) and TDM ages (0.56-0.53 Ga), we suggest the late Carboniferous felsic igneous rocks were produced by partial melting of a juvenile lower crust. The Permian dikes show characteristics of adakite rocks. They have relatively high MgO contents and Mg# values, and positive εNd(t) values (7.2-8.5), which suggest an origin from partial melting of a residual basaltic oceanic crust. We propose that the Aqishan-Yamansu belt was an extensional arc-related basin from ca. 350 to 330 Ma; this was followed by a relatively stable carbonate formation stage at ca. 330-320 Ma, when the Kangguer oceanic slab subducted beneath the Central Tianshan block. As the subduction continued, the Aqishan-Yamansu basin closed due to slab breakoff and rebound during ca. 320-305 Ma, which resulted in basin inversion and the emplacement of granitoids with contemporary Fe-Cu mineralization. During the Permian, the Aqishan-Yamansu belt was in postcollision extension stage, with Permian adakitic dikes formed by partial melting of a residual oceanic crust. © 2021 Geological Society of America. All Rights Reserved.
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184675
作者单位	Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Guangdong Provincial Key Laboratory of Mineral Physics and Materials, 511 Kehua Street, Guangzhou, 510640, China; Department of Geology, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B5E1, Canada; School of Earth Science and Resources, Chang'an University, Xi'an, 710054, China
推荐引用方式 GB/T 7714	Zhang S.,Chen H.,Hollings P.,et al. Tectonic and magmatic evolution of the Aqishan-Yamansu belt: A Paleozoic arc-related basin in the Eastern Tianshan (NW China)[J],2021,133(2021-05-06).
APA	Zhang S.,Chen H.,Hollings P.,Zhao L.,&Gong L..(2021).Tectonic and magmatic evolution of the Aqishan-Yamansu belt: A Paleozoic arc-related basin in the Eastern Tianshan (NW China).Bulletin of the Geological Society of America,133(2021-05-06).
MLA	Zhang S.,et al."Tectonic and magmatic evolution of the Aqishan-Yamansu belt: A Paleozoic arc-related basin in the Eastern Tianshan (NW China)".Bulletin of the Geological Society of America 133.2021-05-06(2021).