气候变化领域集成服务门户(CCPortal): Grenvillean evolution of the Beishan Orogen, NW China: Implications for development of an active Rodinian margin

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DOI	10.1130/B35404.1
	Grenvillean evolution of the Beishan Orogen, NW China: Implications for development of an active Rodinian margin
	Soldner J.; Yuan C.; Schulmann K.; Štípská P.; Jiang Y.; Zhang Y.; Wang X.
发表日期	2020
ISSN	167606
起始页码	1657
结束页码	1680
卷号	132 期号:2021-07-08
英文摘要	New geochemical and geochronological data are used to characterize the geodynamic setting of metasediments, felsic orthogneisses, and eclogite and amphibolite lenses forming the Beishan complex, NW China, at the southern part of the Central Asian Orogenic Belt. The metasediments correspond compositionally to immature greywackes receiving detritus from a heterogeneous source involving a magmatic arc and a Precambrian continental crust. Metagranitoids, represented by felsic orthogneisses, show both composition of greywacke-derived granitic melt with incompatible trace element patterns similar to the host metasediments. The eclogite lenses are characterized by high Nb contents (5.34-27.3 ppm), high (Nb/La)N (>1), and low Zr/Nb ratios (<4.5), which together with variable and negative whole-rock εNd(t) (-4.3 to-10.3) and zircon εHf(t) (-5.0 to + 2.3) values indicate an origin of enriched mantle source as commonly manifested by back-arc basalts at stretched continental margins. Combined with monazite rare earth element analysis, the in situ monazite U-Pb dating of metagraywacke (880.7 ± 7.9) suggests garnet growth during a high-temperature (HT) metamorphic event. Together with U-Pb dating of zircon metamorphic rims in amphibolite (910.9 ± 3.0 Ma), this indicates that the whole crustal edifice underwent a Grenvillian-age metamorphic event. The protolith ages of the eclogite (889.3 ± 4.8 Ma) and orthogneiss (867.5 ± 1.9 Ma) suggest that basalt underplating and sediment melting were nearly coeval with this HT metamorphism. Altogether, the new data allow placing the Beishan Orogen into a Grenvillean geodynamic scenario where: (1) The late Mesoproterozoic to early Neoproterozoic was marked by deposition of the greywacke sequence coeval with formation of an early arc. (2) Subsequently, an asthenospheric upwelling generated basaltic magma underneath the thinned subcontinental mantle lithosphere that was responsible for HT metamorphism, melting of the back-arc basin greywackes and intrusion of granitic magmas. These events correspond to a Peri-Rodinian supra-subduction system that differs substantially from the Neoproterozoic ophiolite sequences described in the Mongolian part of the Central Asian Orogenic Belt, thus indicating important lateral variability of supra-subduction processes along the Rodinian margin. © 2019 Geological Society of America.
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/184752
作者单位	State Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; University of Chinese Academy of Sciences, Beijing, 10069, China; Institut de Physique du Globe de Strasbourg, UMR 7516, University of Strasbourg/School and Observatory of Earth Sciences, Centre National de la Recherche Scientifique, 1 rue Blessig, Strasbourg, F 67084, France; Centre of Lithospheric Research, Czech Geological Survey, Klárov 3, Praha 1, 118 21, Czech Republic; Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
推荐引用方式 GB/T 7714	Soldner J.,Yuan C.,Schulmann K.,et al. Grenvillean evolution of the Beishan Orogen, NW China: Implications for development of an active Rodinian margin[J],2020,132(2021-07-08).
APA	Soldner J..,Yuan C..,Schulmann K..,Štípská P..,Jiang Y..,...&Wang X..(2020).Grenvillean evolution of the Beishan Orogen, NW China: Implications for development of an active Rodinian margin.Bulletin of the Geological Society of America,132(2021-07-08).
MLA	Soldner J.,et al."Grenvillean evolution of the Beishan Orogen, NW China: Implications for development of an active Rodinian margin".Bulletin of the Geological Society of America 132.2021-07-08(2020).