气候变化领域集成服务门户(CCPortal): Two late Carboniferous belts of Nb-enriched mafic magmatism in the Eastern Tianshan: Heterogeneous mantle sources and geodynamic implications

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DOI	10.1130/B35366.1
	Two late Carboniferous belts of Nb-enriched mafic magmatism in the Eastern Tianshan: Heterogeneous mantle sources and geodynamic implications
	Zhang Y.; Yuan C.; Sun M.; Long X.; Huang Z.; Jiang Y.; Li P.; Du L.
发表日期	2020
ISSN	167606
起始页码	1863
结束页码	1880
卷号	132 期号:2021-09-10
英文摘要	Identification of subduction to post-collisional tectonic transitions is critical to the study of orogenic belts. To characterize such a transition in the Tianshan Orogenic Belt, a systematic study was conducted on the late Carboniferous (305-301 Ma) Hongshankou dolerite and Dikan'er basalt of Eastern Tianshan. The Hongshankou dolerites have relatively high Ti and Nb contents, akin to Nb-enriched arc basalts. Based on the Nb/La ratios, these dolerites can be divided into low-Nb/La (0.35-0.40) and high-Nb/La (0.67-1.4) groups, which were likely derived respectively from slab melt-metasomatized mantle wedge and a mixed mantle source involving depleted super-slab and enriched sub-slab asthenospheric components. Like the low-Nb/La dolerites, the Dikan'er basalts possess low Nb/La (0.42-0.46) ratios, suggesting a mantle source previously modified by slab components. In addition, the Dikan'er basalts have variable Nb contents and can be grouped into normal arc basalts and Nb-rich basalts that can be attributed to a common mantle source with different degrees of mantle melting, as demonstrated by the positive correlations of La/Sm with La and Nb. By integrating available data, two late Carboniferous belts of Nb-enriched mafic magmatism are recognized in the Eastern Tianshan, with one in the Yamansu arc (336-301 Ma) and the other in the Bogda Mountains (305-301 Ma). The former is characterized by low Nb/La (<0.6) ratios, reflecting derivation from mantle metasomatized by slab-derived melt during a subduction process; the latter exhibits an abrupt Nb/La increase from 0.6 to 1.4, indicating significant input of sub-slab asthenospheric mantle that was probably induced by slab break off. Accordingly, we propose that the tectonic transition from subduction to post-collision in the Eastern Tianshan occurred in the latest Carboniferous (305-301 Ma) and was marked by the abrupt input of deep and enriched asthenospheric mantle. © 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/184721
作者单位	Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong; State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi'an, 710069, China
推荐引用方式 GB/T 7714	Zhang Y.,Yuan C.,Sun M.,et al. Two late Carboniferous belts of Nb-enriched mafic magmatism in the Eastern Tianshan: Heterogeneous mantle sources and geodynamic implications[J],2020,132(2021-09-10).
APA	Zhang Y..,Yuan C..,Sun M..,Long X..,Huang Z..,...&Du L..(2020).Two late Carboniferous belts of Nb-enriched mafic magmatism in the Eastern Tianshan: Heterogeneous mantle sources and geodynamic implications.Bulletin of the Geological Society of America,132(2021-09-10).
MLA	Zhang Y.,et al."Two late Carboniferous belts of Nb-enriched mafic magmatism in the Eastern Tianshan: Heterogeneous mantle sources and geodynamic implications".Bulletin of the Geological Society of America 132.2021-09-10(2020).