scholarly journals Supplemental Material: Subduction initiation of the western Proto-Tethys Ocean: New evidence from the Cambrian intra-oceanic forearc ophiolitic mélange in the western Kunlun Orogen, NW Tibetan Plateau

2021 ◽  
Author(s):  
Qichao Zhang ◽  
et al.
Keyword(s):  
Tibetan Plateau ◽  
Geochemical Data ◽  
Subduction Initiation ◽  
Ophiolitic Mélange ◽  
Western Kunlun ◽  
Tethys Ocean ◽  
Western Kunlun Orogen ◽  
New Evidence

Detailed petrological and geochemical data.

Subduction initiation of the western Proto-Tethys Ocean: New evidence from the Cambrian intra-oceanic forearc ophiolitic mélange in the western Kunlun Orogen, NW Tibetan Plateau

2021 ◽  
Author(s):  
Qichao Zhang ◽  
Zhong-Hai Li ◽  
Zhenhan Wu ◽  
Xuanhua Chen ◽  
Ji’en Zhang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Subduction Zone ◽  
Geochemical Data ◽  
Subduction Initiation ◽  
Ophiolitic Mélange ◽  
Late Cambrian ◽  
Western Kunlun ◽  
Tethys Ocean ◽  
Subduction Input ◽  
Western Kunlun Orogen

The supra-subduction zone ophiolite or ophiolitic mélange formed in the forearc setting is generally considered to be a key geological record for subduction initiation (SI) with petrological characteristics comparable to the SI-related rock sequence from forearc basalt (FAB) to boninite in the Izu-Bonin-Mariana subduction zone. Nevertheless, the standard FAB and boninite are generally difficult to observe in the forearc rocks generated during SI. Yet, a typical rock sequence indicating the SI of the western Proto-Tethys Ocean is reported for the first time in the Qimanyute intra-oceanic forearc system in the western Kunlun Orogen, Northwest Tibetan Plateau. The magmatic compositions, which range from less to more high field strength element (HFSE)-depleted and large ion lithophile element (LILE)-enriched, are changing from oceanic plagiogranites (ca. 494 Ma) to forearc basalt-like gabbros (FAB-Gs, ca. 487 Ma), boninites, and subsequent Nb-enriched gabbros (NEGs, ca. 485 Ma), which are thus consistent with the Izu-Bonin-Mariana forearc rocks as well as the Troodos and Semail supra-subduction zone-type ophiolites. The geochemical data from the chemostratigraphic succession indicate a subduction initiation process from a depleted mid-oceanic-ridge (MORB)-type mantle source with no detectable subduction input to gradual increasing involvement of subduction-derived materials (fluid/melts and sediments). The new petrological, geochemical, and geochronological data, combined with the regional geology, indicate that the well-sustained FAB-like intrusive magmas with associated boninites could provide crucial evidence for SI and further reveal that the SI of the western Proto-Tethys Ocean occurred in the Late Cambrian (494−485 Ma).

scholarly journals Supplemental Material: Petrogenesis of Ordovician granitoids in Western Kunlun, NW Tibetan Plateau: Insights into the evolution of the Proto-Tethys Ocean

2020 ◽  
Author(s):  
Peng Wang ◽  
Guochun Zhao ◽  
et al.
Keyword(s):  
Tibetan Plateau ◽  
Trace Element ◽  
Partition Coefficients ◽  
Hf Isotope ◽  
Igneous Rocks ◽  
Pb Isotope ◽  
Element Modeling ◽  
Western Kunlun ◽  
Tethys Ocean ◽  
Ordovician Granitoids

Table S1: Zircon U-Pb ages of igneous rocks in the Western Kunlun orogenic belt; Table S2: Results of whole-rock major- (wt%) and trace-element (ppm) data from the three intrusions; Table S3: Zircon U-Pb age of the three intrusions; Table S4: Zircon Hf isotope compositions of the three intrusions; Table S5: Whole-rock Sr-Nd-Pb isotope compositions of the three intrusions; Table S6: Representative analyses of feldspar, amphibole, and pyroxene from the Aqiang and Yutian intrusions; Table S7: Bulk partition coefficients used for trace-element modeling in Figure 14; Figure S1: CL images of zircons showing internal textures and ages of 206Pb/238U (Ma).

scholarly journals Supplemental Material: Petrogenesis of Ordovician granitoids in Western Kunlun, NW Tibetan Plateau: Insights into the evolution of the Proto-Tethys Ocean

2020 ◽  
Author(s):  
Peng Wang ◽  
Guochun Zhao ◽  
et al.
Keyword(s):  
Tibetan Plateau ◽  
Trace Element ◽  
Partition Coefficients ◽  
Hf Isotope ◽  
Igneous Rocks ◽  
Pb Isotope ◽  
Element Modeling ◽  
Western Kunlun ◽  
Tethys Ocean ◽  
Ordovician Granitoids

Table S1: Zircon U-Pb ages of igneous rocks in the Western Kunlun orogenic belt; Table S2: Results of whole-rock major- (wt%) and trace-element (ppm) data from the three intrusions; Table S3: Zircon U-Pb age of the three intrusions; Table S4: Zircon Hf isotope compositions of the three intrusions; Table S5: Whole-rock Sr-Nd-Pb isotope compositions of the three intrusions; Table S6: Representative analyses of feldspar, amphibole, and pyroxene from the Aqiang and Yutian intrusions; Table S7: Bulk partition coefficients used for trace-element modeling in Figure 14; Figure S1: CL images of zircons showing internal textures and ages of 206Pb/238U (Ma).

From folding to transpressional faulting: the Cenozoic Fusha structural belt in front of the Western Kunlun Orogen, northwestern Tibetan Plateau

2016 ◽  
Vol 105 (5) ◽  
pp. 1621-1636 ◽  
Author(s):  
Cong Wang ◽  
Xiao-Gan Cheng ◽  
Han-Lin Chen ◽  
Kang Li ◽  
Xiao-Gen Fan ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Western Kunlun ◽  
Western Kunlun Orogen

Forced subduction initiation within the Neotethys: An example from the mid-Cretaceous Wuntho-Popa arc in Myanmar

2021 ◽  
Author(s):  
Liyun Zhang ◽  
Weiming Fan ◽  
Lin Ding ◽  
Alex Pullen ◽  
Mihai N. Ducea ◽  
...  
Keyword(s):  
Eastern Mediterranean ◽  
Geochemical Data ◽  
Diverse Range ◽  
Subduction Initiation ◽  
The North ◽  
Oceanic Spreading ◽  
Tectonic Settings ◽  
Volcanic Succession ◽  
Subduction System ◽  
New Evidence

Despite decades of research, the mechanisms and processes of subduction initiation remain obscure, including the tectonic settings where subduction initiation begins and how magmatism responds. The Cretaceous Mawgyi Volcanics represent the earliest volcanic succession in the Wuntho-Popa arc of western Myanmar. This volcanic unit consists of an exceptionally diverse range of contemporaneously magmatic compositions which are spatially juxtaposed. Our new geochemical data show that the Mawgyi Volcanics comprise massive mid-oceanic ridge basalt (MORB)-like lavas and dikes, and subordinate island arc tholeiite and calc-alkaline lavas. The Mawgyi MORB-like rocks exhibit flat rare earth elements (REEs) patterns and are depleted in REEs, high field strength elements (except for Th) and TiO2 concentrations relative to those of MORBs, resembling the Izu-Bonin-Mariana protoarc basalts. Our geochronological results indicate that the Mawgyi Volcanics formed between 105 and 93 Ma, coincident with formation of many Neotethyan supra-subduction zone ophiolites and intraoceanic arcs along orogenic strike in the eastern Mediterranean, Middle East, Pakistan, and Southeast Asia. Combined with its near-equatorial paleo-latitudes constrained by previous paleomagnetic data, the Wuntho-Popa arc is interpreted as a segment of the north-dipping trans-Neotethyan subduction system during the mid-Cretaceous. Importantly, our restoration with available data provides new evidence supporting the hypothesis of a mid-Cretaceous initiation of this >8000-km-long subduction system formed by inversion of the ∼E-W−trending Neotethyan oceanic spreading ridges, and that this was contemporaneous with the final breakup of Gondwana and an abrupt global plate reorganization.

scholarly journals Triassic-Jurassic Granitoids and Pegmatites from Western Kunlun-Pamir Syntax: Implications for the Paleo-Tethys Evolution at the Northern Margin of the Tibetan Plateau

Lithosphere ◽  
2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Xiao-Qiang Liu ◽  
Chuan-Lin Zhang ◽  
Haibo Zou ◽  
Qian Wang ◽  
Xiao-Shu Hao ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
The Tibetan Plateau ◽  
Northern Margin ◽  
Magmatic Rocks ◽  
Western Kunlun ◽  
Type Granite ◽  
Tethys Ocean ◽  
Terrane Accretion

Abstract The Western Kunlun-Pamir-Karakorum (WKPK) at the northwestern Tibetan Plateau underwent long-term terrane accretion from the Paleozoic to the Cenozoic. Within this time span, four phases of magmatism occurred in WKPK during the Early Paleozoic, Triassic-Jurassic, Early Cretaceous, and Cenozoic. These voluminous magmatic rocks contain critical information on the evolution of the Tethys Oceans. In this contribution, we provide field observations, petrography, ages, whole-rock elemental and Sr-Nd isotopic compositions, and zircon in situ Lu-Hf isotopes of the Triassic-Jurassic granitoids and pegmatites from the Dahongliutan in Western Kunlun and Turuke area at the Pamir Plateau, in an attempt to constrain their petrogenesis and to decipher a more detailed Paleo-Tethys evolution process. The Dahongliutan pluton is composed of diorites (ca. 210 Ma) and monzogranite (ca. 200 Ma). The diorites have moderate SiO2 (56.77–62.22 wt. %), variable Mg# (46–49), and low Cr (34.4–50.6 ppm) and Ni contents (7.0–14.5 ppm). They show LREE-enriched patterns (LaN/YbN=4.3–17), with variable negative Eu anomalies (0.63–0.91) and variable ratios of Nb/La (0.27–0.97). Isotopically, the diorites display enriched whole-rock εNdt (-5.43 to -7.67) and negative to positive zircon εHft values (-6.6 to 0.4). They were most likely generated by melting of a subduction-modified mantle source with subsequent assimilation and fractional crystallization. The Turuke monzogranites (ca. 202–197 Ma) have S-type granite characteristics and are characterized by high SiO2 (70.36–76.12 wt. %) and A/CNK values (1.19–1.36), variable LREE-enriched patterns (LaN/YbN=8.87–14.40), negative Eu anomaly (0.07–0.56), relatively uniform whole-rock εNdt (-10.49 to -11.22), and variable negative zircon εHft values (-10.7 to -1.3). They were probably generated by muscovite-dehydration melting of dominantly metapelitic sources. The widespread pegmatites (ca. 195 Ma) at the Dahongliutan area record an extensional setting after the collision of Karakorum with the South Kunlun-Tianshuihai terrane. Combining our new data with the previous studies, we propose a divergent double-sided subduction of the Paleo-Tethys Ocean (243–208 Ma) and a gradual closure of the Paleo-Tethys Ocean from east (ca. 200 Ma) to west (ca. 180 Ma) to explain the Triassic-Jurassic tectono-magmatism in the WKPK.

scholarly journals Timing of the Meso-Tethys Ocean opening: Evidence from Permian sedimentary provenance changes in the South Qiangtang Terrane, Tibetan Plateau

2021 ◽  
Vol 567 ◽  
pp. 110265
Author(s):  
Jian-Jun Fan ◽  
Yaoling Niu ◽  
An-Bo Luo ◽  
Chao-Ming Xie ◽  
Yu-Jie Hao ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
The South ◽  
Sedimentary Provenance ◽  
Tethys Ocean ◽  
Qiangtang Terrane
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