Geodynamics of the divergent double subduction along the Bangong-Nujiang tethyan suture zone: Insights from late mesozoic intermediate-mafic rocks in central Tibet

2020 ◽  
Vol 79 ◽  
pp. 233-247 ◽  
Author(s):  
Huichuan Liu ◽  
Qiangtai Huang ◽  
I. Tonguç Uysal ◽  
Zhourong Cai ◽  
Zhifeng Wan ◽  
...  
Keyword(s):  
Suture Zone ◽  
Mafic Rocks ◽  
Late Mesozoic ◽  
Central Tibet

Morphology and geochemistry of zircons from late Mesozoic igneous complexes in coastal SE China: implications for petrogenesis

2002 ◽  
Vol 66 (2) ◽  
pp. 235-251 ◽  
Author(s):  
X. Wang ◽  
W. L. Griffin ◽  
S. Y. O’Reilly ◽  
X. M. Zhou ◽  
X. S. Xu ◽  
...  
Keyword(s):  
Growth Stages ◽  
Continental Margins ◽  
Calc Alkaline ◽  
Mafic Rocks ◽  
Late Mesozoic ◽  
Igneous Complexes ◽  
Basaltic Magmas ◽  
Morphological Indices ◽  
Active Continental Margins ◽  
Se China

AbstractThe Pingtan and Tonglu igneous complexes in SE China are typical of the calc-alkaline series developed at active continental margins. These two complexes are dominated by felsic rocks, temporally and spatially associated with minor mafic rocks. Morphological and trace-element studies of zircon populations in rocks from each of these complexes show that the zircon populations may be divided into 3–4 distinct growth stages, characterized by different distributions of morphological indices (Ipr, Ipy and Iel), and different contents of the substituting elements (Hf, U, Th, Y and P). The four growth stages recognized in the zircons are believed to have formed successively in the magma chamber, during the emplacement, and in the early and later stages of magma consolidation, respectively. All four stages are recognized in the plutonic Pingtan complex, whereas the stages 3 and 4 are less developed in the volcanic/subvolcanic Tonglu complex. Based on the chemistry and morphology of the different zircon populations of the Pingtan and Tonglu complexes, it is suggested that basaltic magmas underplating at the boundary between crust and mantle caused partial melting of the mid–lower crust and produced granitoid magmas. Subsequently, mixing between magmas was important.

Geological setting and geochemical signatures of the mafic rocks from the Intra-Pontide Suture Zone: implications for the geodynamic reconstruction of the Mesozoic Neotethys

2015 ◽  
Vol 105 (1) ◽  
pp. 39-64 ◽  
Author(s):  
Kaan Sayit ◽  
Michele Marroni ◽  
M. Cemal Göncüoglu ◽  
Luca Pandolfi ◽  
Alessandro Ellero ◽  
...  
Keyword(s):  
Suture Zone ◽  
Mafic Rocks ◽  
Geological Setting

Closure of the Bangong–Nujiang Tethyan Ocean in the central Tibet: Results from the provenance of the Duoni Formation

2019 ◽  
Vol 89 (10) ◽  
pp. 1039-1054 ◽  
Author(s):  
Zhicai Zhu ◽  
Qingguo Zhai ◽  
Peiyuan Hu ◽  
Sunlin Chung ◽  
Yue Tang ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
Suture Zone ◽  
The Tibetan Plateau ◽  
Tectonic History ◽  
Magmatic Rocks ◽  
Two Samples ◽  
Delta Sequence ◽  
History Of ◽  
Central Tibet

ABSTRACT The closure of the Bangong–Nujiang Tethyan Ocean (BNTO) and consequent Lhasa–Qiangtang collision is vital to reasonably understanding the early tectonic history of the Tibetan Plateau before the India-Eurasia collision. The timing of the Lhasa–Qiangtang collision was mainly constrained by the ophiolite and magmatic rocks in previous studies, with only limited constraints from the sedimentary rocks within and adjacent to the Bangong–Nujiang suture zone. In the middle segment of the Bangong–Nujiang suture zone, the Duoni Formation, consisting of a fluvial delta sequence with minor andesite interlayers, was originally defined as the Late Cretaceous Jingzhushan Formation and interpreted as the products of the Lhasa–Qiangtang collision during the Late Cretaceous. Our new zircon U-Pb data from two samples of andesite interlayers demonstrate that it was deposited during the latest Early Cretaceous (ca. 113 Ma) rather than Late Cretaceous. Systemic studies on the sandstone detrital model, heavy-mineral assemblage, and clasts of conglomerate demonstrate a mixed source of both Lhasa and Qiangtang terranes and ophiolite complex. Clasts of conglomerate contain abundant angular peridotite, gabbro, basalt, chert, andesite, and granite, and minor quartzite and gneiss clasts also exist. Sandstones of the Duoni Formation are dominated by feldspathic–lithic graywacke (Qt25F14L61 and Qm13F14L73), indicative of a mixture of continental-arc and recycled-orogen source origin. Detrital minerals of chromite, clinopyroxene, epidote, and hornblende in sandstone also indicate an origin of ultramafic and mafic rocks, while garnets indicate a metamorphosed source. Paleocurrent data demonstrate bidirectional (southward and northward) source origins. Thus, we suggest that the deposition of the Duoni Formation took place in the processes of the Lhasa–Qiangtang collision during the latest Early Cretaceous (∼ 113 Ma), and the BNTO had been closed by this time.

Collisional processes between the Qiangtang Block and the Lhasa Block: Insights from structural analysis of the Bangong–Nujiang Suture Zone, central Tibet

2019 ◽  
Vol 54 (2) ◽  
pp. 946-960 ◽  
Author(s):  
Runhua Guo ◽  
Sanzhong Li ◽  
Shengyao Yu ◽  
Liming Dai ◽  
Yongjiang Liu ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Suture Zone ◽  
Central Tibet
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