Early Cretaceous exhumation of the Qiangtang Terrane during collision with the Lhasa Terrane, Central Tibet

Terra Nova ◽  
2017 ◽  
Vol 29 (6) ◽  
pp. 382-391 ◽  
Author(s):  
Zhongbao Zhao ◽  
Paul D. Bons ◽  
Konstanze Stübner ◽  
Gen-Hou Wang ◽  
Todd A. Ehlers
Keyword(s):  
Early Cretaceous ◽  
Lhasa Terrane ◽  
Central Tibet ◽  
Qiangtang Terrane

Co-seismic surface ruptures in Qiangtang Terrane: Insight into Late Cenozoic deformation of central Tibet

2019 ◽  
Vol 750 ◽  
pp. 359-378 ◽  
Author(s):  
Shuai Han ◽  
Haibing Li ◽  
Jiawei Pan ◽  
Haijian Lu ◽  
Yong Zheng ◽  
...  
Keyword(s):  
Late Cenozoic ◽  
Surface Ruptures ◽  
Central Tibet ◽  
Qiangtang Terrane ◽  
Insight Into

Late Eocene post-collisional magmatic rocks from the southern Qiangtang terrane record the melting of pre-collisional enriched lithospheric mantle

2021 ◽  
Author(s):  
Yue Qi ◽  
Qiang Wang ◽  
Gang-jian Wei ◽  
Xiu-Zheng Zhang ◽  
Wei Dan ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Trace Element ◽  
Partial Melting ◽  
Early Cretaceous ◽  
Lithospheric Mantle ◽  
Late Eocene ◽  
The Tibetan Plateau ◽  
Mafic Rocks ◽  
Isotopic Compositions ◽  
Qiangtang Terrane

Diverse rock types and contrasting geochemical compositions of post-collisional mafic rocks across the Tibetan Plateau indicate that the underlying enriched lithospheric mantle is heterogeneous; however, how these enriched mantle sources were formed is still debated. The accreted terranes within the Tibetan Plateau experienced multiple stages of evolution. To track the geochemical characteristics of their associated lithospheric mantle through time, we can use mantle-derived magmas to constrain the mechanism of mantle enrichment. We report zircon U-Pb ages, major and trace element contents, and Sr-Nd isotopic compositions for Early Cretaceous and late Eocene mafic rocks in the southern Qiangtang terrane. The Early Cretaceous Baishagang basalts (107.3 Ma) are characterized by low K2O/Na2O (<1.0) ratios, arc-like trace element patterns, and uniform Sr-Nd isotopic compositions [(87Sr/86Sr)i = 0.7067−0.7073, εNd(t) = −0.4 to −0.2]. We suggest that the Baishagang basalts were derived from partial melting of enriched lithospheric mantle that was metasomatized by subducted Bangong−Nujiang oceanic material. We establish the geochemistry of the pre-collisional enriched lithospheric mantle under the southern Qiangtang terrane by combining our data with those from other Early Cretaceous mafic rocks in the region. The late Eocene (ca. 35 Ma) post-collisional rocks in the southern Qiangtang terrane have low K2O/Na2O (<1.0) ratios, and their major element, trace element, and Sr-Nd isotopic compositions [(87Sr/86Sr)i = 0.7042−0.7072, εNd(t) = −4.5 to +1.5] are similar to those of the Early Cretaceous mafic rocks. Based on the distribution, melting depths, and whole-rock geochemical compositions of the Early Cretaceous and late Eocene mafic rocks, we argue that the primitive late Eocene post-collisional rocks were derived from pre-collisional enriched lithospheric mantle, and the evolved samples were produced by assimilation and fractional crystallization of primary basaltic magma. Asthenosphere upwelling in response to the removal of lithospheric mantle induced the partial melting of enriched lithospheric mantle at ca. 35 Ma.

Late Jurassic Nb‐enriched basalts from the Bilong Co area in the southern Qiangtang Terrane, central Tibet, and their implications

2021 ◽  
Author(s):  
Jianbo Cheng ◽  
Yalin Li ◽  
Haiyang He ◽  
Siqi Xiao ◽  
Wenjun Bi ◽  
...  
Keyword(s):  
Late Jurassic ◽  
Central Tibet ◽  
Qiangtang Terrane

Passive-margin magmatism caused by enhanced slab-pull forces in central Tibet

Geology ◽  
2020 ◽  
Author(s):  
Wei Dan ◽  
Qiang Wang ◽  
William M. White ◽  
Xian-Hua Li ◽  
Xiu-Zheng Zhang ◽  
...  
Keyword(s):  
Passive Margin ◽  
Lower Plate ◽  
Isotopic Signatures ◽  
Ridge Subduction ◽  
Slab Rollback ◽  
Element Enrichment ◽  
Central Tibet ◽  
Back Arc ◽  
Ocean Ridge ◽  
Qiangtang Terrane

We report on a ca. 239 Ma mafic dike swarm intruded in the Southern Qiangtang terrane, central Tibet, that was generated on the passive continental margin of a subducting lower plate. The dikes are tholeiitic basalts and exhibit light rare earth element enrichment, modest negative anomalies in Nb and Ta, and enriched isotopic signatures. The dikes are coeval with a back-arc basin formed in the upper plate as a result of the rollback of the Paleo-Tethys oceanic slab. Thus, after ocean-ridge subduction, enhanced slab-pull forces related to slab rollback on one side of the ocean induced extension and magmatism in the passive margin on the opposite side. We argue that enhanced slab-pull forces are a previously unrecognized mechanism for the generation of lower-plate passive-margin magmatism.

Sign in / Sign up

Export Citation Format

Share Document