DOI: 10.1007/s00531-013-0900-x
Scopus记录号: 2-s2.0-84881611182
论文题名: Magma mixing revealed from in situ zircon U-Pb-Hf isotope analysis of the Muhuguan granitoid pluton, eastern Qinling Orogen, China: Implications for late Mesozoic tectonic evolution
作者: Liu R. ; Li J.-W. ; Bi S.-J. ; Hu H. ; Chen M.
刊名: International Journal of Earth Sciences
ISSN: 14373254
出版年: 2013
卷: 102, 期: 6 起始页码: 1583
结束页码: 1602
语种: 英语
英文关键词: Eastern Qinling Orogen
; Hf isotope
; Lithospheric extension
; Magma mixing
; Zircon U-Pb age
Scopus关键词: continental margin
; granitoid
; hafnium
; igneous intrusion
; in situ measurement
; isotopic composition
; Jurassic
; lamprophyre
; magmatic differentiation
; orogeny
; Pacific plate
; Paleozoic
; partial melting
; Proterozoic
; uranium-lead dating
; zircon
; China
; Qinling Mountains
英文摘要: In this paper, we present zircon U-Pb age and Hf isotope data to document the significance of magma mixing in the formation of Late Jurassic granitoid intrusions in the eastern Qinling Orogen, China. The Muhuguan granitoid pluton from this orogen consists of monzogranite and lesser biotite granite and granodiorite, all containing abundant hornblende-rich cumulates, dioritic xenoliths, and mafic magmatic enclaves (MMEs). The monzogranite and granodiorite are intruded by a number of lamprophyre dykes. Both a cumulate and a dioritic xenolith samples have concordant zircon U-Pb ages of ca. 161 ± 1 Ma, but possess contrasting Hf isotopic compositions. The cumulate has more radiogenic zircon Hf isotopes with negative ε Hf(t) values (-7.9 to -2.5) and T DM1 ages of 0.9-1.1 Ga, indicating its derivation likely from basaltic rocks of the Neoproterozoic to early Paleozoic Kuanping Group in the area. The dioritic xenolith has much lower zircon ε Hf(t) values of -19.5 to -8.8 and T DM2 ages of 2.4-1.7 Ga, consistent with a juvenile Paleoproterozoic crust source presumably represented by the metabasic rocks of the Qinling Group in the area. Individual samples of the monzogranite, MME, and a lamprophyre dyke have U-Pb ages of 150 ± 1, 152 ± 1, and 152 ± 1 Ma, respectively, demonstrating coeval mafic and felsic magmatism in the Late Jurassic. The lamprophyre dyke has homogeneous, highly negative zircon ε Hf(t) values (-29.8 to -24.8) and Archean T DM2 ages (3.0-2.7 Ga), and its genesis is interpreted as partial melting of an ancient enriched subcontinental mantle source. Zircons from the fine-grained MME show a large range of ε Hf(t) between -29.1 and -9.8, overlapping values of the monzogranite and lamprophyre dyke samples. Zircon U-Pb age and Hf isotopes of the MMEs are consistent with their formation by mixing of crustal- and enriched mantle-derived magmas. The main group of zircons from the monzogranite has ε Hf(t) values (-17.9 to -9.3) and T DM2 ages (2.3-1.8 Ga) that are compatible with the dioritic xenoliths, indicating that the former was produced by partial melting of Paleoproterozoic crustal source with involvement of mantle-derived magmas. Mafic magmatism revealed from the Muhuguan pluton indicates that the eastern Qinling Orogen was dominated by lithospheric extension during the Late Jurassic. Compilation of existing geological and geochronological data suggests that this extensional event started in Late Jurassic (ca. 160 Ma) and persisted into the Early Cretaceous until ca. 110 Ma. The Jura-Cretaceous extension may have resulted from the late Mesozoic westward subduction of the Pacific plate beneath the East Asian continental margin. © 2013 Springer-Verlag Berlin Heidelberg. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881611182&doi=10.1007%2fs00531-013-0900-x&partnerID=40&md5=e4338b4378b439833d1626b5b4e4bf5a
Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/70524
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
There are no files associated with this item.
作者单位: State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences (Wuhan), Wuhan, 430074, China; Faculty of Earth Resources, China University of Geosciences (Wuhan), Wuhan, 430074, China; Hubei Geological Survey, Wuhan, 430034, China
Recommended Citation:
Liu R.,Li J.-W.,Bi S.-J.,et al. Magma mixing revealed from in situ zircon U-Pb-Hf isotope analysis of the Muhuguan granitoid pluton, eastern Qinling Orogen, China: Implications for late Mesozoic tectonic evolution[J]. International Journal of Earth Sciences,2013-01-01,102(6)