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The West Kunlun orogenic belt (WKOB) at the northwest margin of the Greater Tibetan Plateau records seafloor subduction, ocean basin closing and continental collision with abundant syncollisional granitoids in response to the evolution of the Proto- and Paleo-Tethys Oceans from the early-Paleozoic to the Triassic. Here we present a combined study of detailed zircon U-Pb geochronology, whole-rock major...
Mafic intrusive rocks are widely exposed in the Motuo tectono-magmatic belt, southeast Lhasa terrane. LA–ICP-MS U–Pb zircon dating shows that they have magma crystallization ages of 69 and ca. 50Ma. These mafic intrusive rocks are characterized by variable SiO2 (44.60–57.60wt.%), high Al2O3 (17.19–20.86wt.%), and low MgO (1.85–5.38wt.%) with Mg# of 31–55. Their chemical composition is comparable with...
Jiru is a poorly studied Cu deposit located in the west segment of the Gangdese porphyry Cu belt (GPCB), 200km west of Lhasa. The deposit consists of both collisional- and postcollisional-stage porphyry-type Cu systems, which are genetically associated with the early Eocene granitoid batholith and the Miocene Jiru porphyry stock, respectively. In this study, we present zircon U–Pb LA-ICP-MS dates...
Phanerozoic growth of continental crust has widely been considered as an important geological phenomenon and mainly occurs in an arc setting. However, the crustal growth models (mantle-derived basalt underplating or accretion of island or intra-oceanic arc complexes or oceanic plateau) have been disputed. Here we present new zircon LA–ICPMS U–Pb age, whole-rock major and trace element, Sr–Nd and zircon...
The Western Nyainqentanglha (WNT) mountain range of south-central Tibet predominantly comprises granitoids that intrude into metasedimentary strata, and was exhumed from ~15 to 20km depth in the footwall of the Yangbajain graben during the late Neogene. The range provides a rare exposure of deeper crustal levels of Tibet, which can be used to gain insight into processes that may be occurring beneath...
We present zircon U–Pb ages and geochemical data on the late Triassic mafic dikes (diabase) and felsic volcanic rocks (rhyolite and rhyolitic tuffs) in the East Kunlun Orogenic Belt (EKOB). These rocks give a small age window of 228–218Ma. The mafic dikes represent evolved alkaline basaltic melts intruding ~8–9Myrs older and volumetrically more abundant A-type granite batholith. Their rare earth element...
The Bangong–Nujiang suture zone (BNSZ) is located in the central Tibetan Plateau, and represents the relict of the Bangong–Nujiang Tethyan Ocean (BNTO). This paper presents zircon U–Pb ages and whole-rock geochemical and Sr–Nd isotope data for the ophiolitic rocks from the Rutog, Dongco, Dongqiao, Amdo, and Dengqen areas (from west to east) in the BNSZ. Zircon U–Pb ages obtained from five gabbros...
The discovery of diamonds and highly reduced minerals in podiform chromitites, which have generally been interpreted as magmatic rocks formed from partial melts of upper mantle peridotites under low-pressure conditions, has raised many questions about the origin of these enigmatic bodies.In order to provide experimental constraints on the formation and emplacement of podiform chromititesin ophiolites,...
We report new whole-rock geochemical and Sr–Nd–Pb isotope and zircon U–Pb age and Hf isotope data of the Hongshan intrusive suite in the Triassic Yidun Terrane, eastern Tibet. These data allow us to explore the possible causative links between the magmatism and the coeval Cu–Mo mineralization in the region. The Hongshan intrusive rocks have SiO2 of 65.06–73.60wt.%, K2O of 3.17–6.41wt.%, and P2O5 of...
Eocene magmatic rocks are widespread in western Yunnan, southeastern Tibetan Plateau. However, their petrogenesis and tectonic significance remain controversial. In this paper, we report geochemical and geochronological data of adakite-like rocks from the eastern part of western Yunnan. Zircon U–Pb dating reveals that they were emplaced at ca. 35Ma. A geochemical study shows that these rocks have...
Cenozoic active structures in the Tibetan Plateau are mainly regional N–S trending extensional faults and grabens, and E–W trending extensional tracks that are related to the transition from syn- to post-collision between India and Asia. E–W trending tracks are parallel to the direction of Neo-Tethyan oceanic convergence and consist of extensional volcanic–sedimentary basins and magmatic dykes in...
Peraluminous granitic magmatism in the Baoshan block is long-lasting roughly from 500Ma to 450Ma. The petrogenesis and geodynamics for this long-lived magmatism remain controversial. To address this controversy, this study reports the zircon U–Pb age and Hf-isotope, and bulk-rock major and trace element data of the granites from the Shuangmaidi and Mengmao areas in the Baoshan block. LA-ICPMS zircon...
This study presents geochemical compositions of mafic rocks outcropped in the Luobusa ophiolite that locates at the eastern part of the Yarlung Zangbo Suture Zone (YZSZ). The studied mafic rocks include gabbroic/diabase dykes cutting the peridotites and foliated amphibolites embedded within the subophiolitic mélange. The diabases have low K2O contents and display N-MORB-like geochemical characteristics,...
The lack of magmatic records with high-quality geochronological and geochemical data in the central segment of the southern Qiangtang subterrane in central Tibet inhibits a complete understanding of the subduction polarity of the Bangong–Nujiang Ocean lithosphere during the Mesozoic. In this study, we present the zircon U–Pb age as well as geochemical and Sr–Nd–Pb isotopic data for the Late Jurassic...
Late Cenozoic volcanism occurred in the central Myanmar basin, a region that is marked by the existence of the dextral Sagaing fault linking the eastern Himalayan Syntaxis to the north and the Andaman Sea to the south. Here we report new geochemical data of volcanic rocks from Monywa, Mt. Popa and Singu areas erupting in two distinct stages, i.e., mid-Miocene and Quaternary, respectively. While calc-alkaline...
The key to gaining a better understanding of Paleotethyan tectonic evolution is to determine the tectonic setting of the main suture/tectonic zones and their relationships in SE Asia. The Luang Prabang tectonic zone in NW Laos lies in the area that aligns with the Jinshajiang–Ailaoshan suture zone to the north and the Nan suture zone to the south. Correlations among them have been debated. Samples...
The Late Paleozoic tectonic evolution of the Lhasa terrane remains poorly understood due to the paucity of the Late Paleozoic magmatic rocks exposed at the surface. Detrital zircons in the sedimentary rocks can provide a record of magmatic rocks that have been eroded. Here we report detrital zircon U-Pb ages, trace-element and Hf isotopic data of metasedimentary rocks from the Nyingchi Complex in...
Integration of lithostratigraphic, magmatic, and metamorphic data from the Lhasa–Qiangtang collision zone in central Tibet (including the Bangong suture zone and adjacent regions of the Lhasa and Qiangtang terranes) indicates assembly through divergent double sided subduction. This collision zone is characterized by the absence of Early Cretaceous high-grade metamorphic rocks and the presence of extensive...
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