DOI: 10.1007/s00531-015-1220-0
Scopus记录号: 2-s2.0-84961794988
论文题名: Origins of Early Mesozoic granitoids and their enclaves from West Kunlun, NW China: implications for evolving magmatism related to closure of the Paleo-Tethys ocean
作者: Wang C. ; Liu L. ; Korhonen F. ; Yang W.-Q. ; Cao Y.-T. ; He S.-P. ; Zhu X.-H. ; Liang W.-T.
刊名: International Journal of Earth Sciences
ISSN: 14373254
出版年: 2016
卷: 105, 期: 3 起始页码: 941
结束页码: 964
语种: 英语
英文关键词: Microgranular enclaves
; Post-collisional granite
; Slab break-off
; Tethys Ocean
; West Kunlun
Scopus关键词: continental collision
; enclave
; granitoid
; magmatism
; Mesozoic
; partial melting
; suture zone
; tectonic evolution
; Tethys
; uranium-lead dating
; zircon
; China
; Kunlun Mountains
英文摘要: Early Mesozoic granitoids and microgranular enclaves (MEs) are widespread in the West Kunkun, northwestern Tibetan plateau, and record the tectonic evolution of Eurasia–Tethys in this area. This study reports geochemistry, zircon U–Pb and Hf isotopic data for a suite of granitoids and their MEs from the Middle Triassic Bulunkou pluton (BP) and the Late Triassic Akazishan pluton (AP) from the West Kunlun. LA-ICP-MS U–Pb zircon dating of a sample from the BP host monzogranite and an enclave, as well as a AP monzogranite, yielded ages of 236 ± 2, 230 ± 7 and 208 ± 1 Ma, respectively. The BP monzogranite and its enclaves from the northwestern part of the West Kunlun are mainly weakly peraluminous granites characterised by relatively high Rb, Th, Rb/Sr (2.64–9.03) and HREE contents, and low Mg#, Sr/Y and negative Eu anomalies. Zircons from the BP monzogranite have εHf(t) values from −5.7 to −1.6. Zircons from enclaves of the BP show more variable εHf(t) values from −4.1 to 3.8. We consider that the BP granites are likely to have been formed by partial melting of metasedimentary rocks at shallow crustal depth, and their enclaves, composed of quartz + biotite + plagioclase + garnet + K-feldspar, are relics from the melting of a source at middle crustal depths. The AP host and its enclaves from the southeastern part of the West Kunlun have low Rb, Rb/Sr (0.15–1.90) and weakly negative Eu anomalies but high HREE contents indicating limited fractionation of plagioclase without residual garnet in their source. The inferred protolith is an intermediate igneous rock in the middle or lower crust. MEs hosted in the AP have high Mg# (39.7–45.0) and Nb and weakly negative Eu anomalies, as well as high Sr, P and Ti, corresponding to a medium-K basaltic rock, which may have originated from mixing of partial melting of metasomatised mantle wedge that has been modified by upwelling asthenospheric mantle and crustal melting in the deep source. Post-collisional southeasternward younging of Mesozoic granitoids in the West Kunlun records a transition from shallow level, mid-crustal melting to deeper level, lower-crustal melting. The post-collisional granitoids show significant mantle input increasing from northwest to southeast, which was closely associated with mafic magma-driven partial melting of mantle and crustal sources as a consequence of slab break-off. Syn- to post-collisional Early Mesozoic granites emplaced along the Mazar–Kangxiwar suture zone suggest that these tectonomagmatic processes followed the closure of the Paleo-Tethys ocean during the Tarim and Karakorum–Qiangtang continental collision. © 2015, Springer-Verlag Berlin Heidelberg. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84961794988&doi=10.1007%2fs00531-015-1220-0&partnerID=40&md5=e56bed473b70db1571718bce5bf4122c
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/70179
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi’an, China; MLR Key Laboratory of Genesis and Exploration of Magmatic Ore Deposits, Xi’an Center of Geological Survey, China Geological Survey, Xi’an, China; Geological Survey of Western Australia, 100 Plain Street, East Perth, WA, Australia; College of Geological Science and Engineering, Shandong University of Science, and Technology, Qingdao, China
Recommended Citation:
Wang C.,Liu L.,Korhonen F.,et al. Origins of Early Mesozoic granitoids and their enclaves from West Kunlun, NW China: implications for evolving magmatism related to closure of the Paleo-Tethys ocean[J]. International Journal of Earth Sciences,2016-01-01,105(3)