Petrology, geochemistry and geochronology of gabbros from the Zhongcang ophiolitic mélange, central Tibet: Implications for an intra-oceanic subduction zone within the Neo-Tethys Ocean

2014 ◽  
Vol 25 (2) ◽  
pp. 224-240 ◽  
Author(s):  
Mengjing Xu ◽  
Cai Li ◽  
Wei Xu ◽  
Chaoming Xie ◽  
Peiyuan Hu ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Ophiolitic Mélange ◽  
Tethys Ocean ◽  
Central Tibet

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).

Middle Permian adakitic granite dikes in the Sumdo region, central Lhasa terrane, central Tibet: Implications for the subduction of the Sumdo Paleo-Tethys Ocean

2021 ◽  
Vol 205 ◽  
pp. 104610
Author(s):  
Bin Wang ◽  
Chao-Ming Xie ◽  
Yong-sheng Dong ◽  
Jian-Jun Fan ◽  
Yun-Peng Yu ◽  
...  
Keyword(s):  
Middle Permian ◽  
Lhasa Terrane ◽  
Tethys Ocean ◽  
Central Tibet

scholarly journals Tectonic evolution and high-pressure rock exhumation in the Qiangtang Terrane, Central Tibet

2015 ◽  
Vol 7 (1) ◽  
pp. 329-367 ◽  
Author(s):  
Z. Zhao ◽  
P. D. Bons ◽  
G. Wang ◽  
A. Soesoo ◽  
Y. Liu
Keyword(s):  
High Pressure ◽  
Tectonic Evolution ◽  
Late Triassic ◽  
The South ◽  
Metamorphic Belt ◽  
The North ◽  
Ophiolitic Mélange ◽  
Basement Rocks ◽  
Central Tibet ◽  
Qiangtang Terrane

Abstract. Conflicting interpretations of the > 500 km long, east-west trending Qiangtang Metamorphic Belt have led to very different and contradicting models for the Permo-Triassic tectonic evolution of Central Tibet. We define two metamorphic events, one that only affected Pre-Ordovician basement rocks and one subduction-related Triassic high-pressure metamorphism event. Detailed mapping and structural analysis allowed us to define three main units that were juxtaposed due to collision of the North and South Qiangtang terranes after closure of the Ordovician-Triassic ocean that separated them. The base is formed by the Precambrian-Carboniferous basement, followed by non-metamorphic ophiolitic mélange, containing mafic rocks that range in age from the Ordovician to Middle Triassic. The top of the sequence is formed by strongly deformed sedimentary mélange that contains up to > 10 km size rafts of both un-metamorphosed Permian sediments and high-pressure blueschists. We propose that the high-pressure rocks were exhumed from underneath the South Qiangtang Terrane in an extensional setting caused by the pull of the northward subducting slab of the Shuanghu-Tethys. High-pressure rocks, sedimentary mélange and margin sediments were thrust on top of the ophiolitic mélange that was scraped off the subducting plate. Both units were subsequently thrust on top of the South Qiantang Terrane continental basement. Onset of Late Triassic sedimentation marked the end of the amalgamation of both Qiangtang terranes and the beginning of spreading between Qiantang and North Lhasa to the south, leading to the deposition of thick flysch deposits in the Jurassic.

Triassic continental subduction in central Tibet and Mediterranean-style closure of the Paleo-Tethys Ocean

Geology ◽  
2008 ◽  
Vol 36 (5) ◽  
pp. 351 ◽  
Author(s):  
Alex Pullen ◽  
Paul Kapp ◽  
George E. Gehrels ◽  
Jeff D. Vervoort ◽  
Lin Ding
Keyword(s):  
Continental Subduction ◽  
Tethys Ocean ◽  
Central Tibet

Cretaceous structures in the Duolong region of central Tibet: Evidence for an accretionary wedge and closure of the Bangong–Nujiang Neo-Tethys Ocean

2017 ◽  
Vol 48 ◽  
pp. 110-123 ◽  
Author(s):  
Yiming Liu ◽  
Ming Wang ◽  
Cai Li ◽  
Chaoming Xie ◽  
Hongqi Chen ◽  
...  
Keyword(s):  
Accretionary Wedge ◽  
Tethys Ocean ◽  
Central Tibet

Discovery of a dismembered metamorphic sole in the Saga ophiolitic mélange, South Tibet: Assessing an Early Cretaceous disruption of the Neo-Tethyan supra-subduction zone and consequences on basin closing

2012 ◽  
Vol 22 (2) ◽  
pp. 398-414 ◽  
Author(s):  
Carl Guilmette ◽  
Réjean Hébert ◽  
Jaroslav Dostal ◽  
Aphrodite Indares ◽  
Thomas Ullrich ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Early Cretaceous ◽  
Ophiolitic Mélange ◽  
South Tibet

scholarly journals Tectonic evolution and high-pressure rock exhumation in the Qiangtang terrane, central Tibet

Solid Earth ◽  
2015 ◽  
Vol 6 (2) ◽  
pp. 457-473 ◽  
Author(s):  
Z. Zhao ◽  
P. D. Bons ◽  
G. Wang ◽  
A. Soesoo ◽  
Y. Liu
Keyword(s):  
High Pressure ◽  
Tectonic Evolution ◽  
Late Triassic ◽  
The South ◽  
Metamorphic Belt ◽  
The North ◽  
Ophiolitic Mélange ◽  
Basement Rocks ◽  
Central Tibet ◽  
Qiangtang Terrane

Abstract. Conflicting interpretations of the > 500 km long, east–west-trending Qiangtang metamorphic belt have led to very different and contradicting models for the Permo–Triassic tectonic evolution of central Tibet. We define two metamorphic events, one that only affected pre-Ordovician basement rocks and one subduction-related Triassic high-pressure metamorphism event. Detailed mapping and structural analysis allowed us to define three main units that were juxtaposed due to collision of the north and south Qiangtang terranes after closure of the Ordovician–Triassic ocean that separated them. The base is formed by the Precambrian–Carboniferous basement, followed by non-metamorphic ophiolitic mélange containing mafic rocks that range in age from the Ordovician to Middle Triassic. The top of the sequence is formed by strongly deformed sedimentary mélange that contains up to > 10 km size rafts of both unmetamorphosed Permian sediments and high-pressure blueschists. We propose that the high-pressure rocks were exhumed from underneath the south Qiangtang terrane in an extensional setting caused by the pull of the northward subducting slab of the Shuanghu–Tethys. High-pressure rocks, sedimentary mélange and margin sediments were thrust on top of the ophiolitic mélange that was scraped off the subducting plate. Both units were subsequently thrust on top of the south Qiantang terrane continental basement. Onset of Late Triassic sedimentation marked the end of the amalgamation of both Qiangtang terranes and the beginning of spreading between Qiantang and north Lhasa to the south, leading to the deposition of thick flysch deposits in the Jurassic.

Sign in / Sign up

Export Citation Format

Share Document