The subduction-accretion history of the Bangong-Nujiang Ocean: Constraints from provenance and geochronology of the Mesozoic strata near Gaize, central Tibet

Li, Shun; Ding, Lin; Guilmette, Carl; Fu, Jiajun; Xu, Qiang; Yue, Yahui; Henrique-Pinto, Renato

doi:10.1016/j.tecto.2017.02.023

Cited by 93 publications

(68 citation statements)

References 61 publications

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“…The Mugagangri Group represents the accretionary complex formed during northward subduction of the Bangong‐Nujiang ocean [ Huang et al , ; Li et al , ; Zeng et al , ]. This mélange of the Mugagangri Group in the studied area contains limestone, chert, basalt, and sandstone blocks similar to the mélange in Gaize [ Huang et al , ; Li et al , ; Zeng et al , ], and is widely exposed from west to east to the north of Selingco along the suture zone. The accretion of the Gaaco Formation implies that the deep‐sea edge of the southern Qiangtang basin was disrupted during the growth of accretionary complex.…”

Section: Interpretation and Discussionmentioning

confidence: 99%

“…Slate, metamorphic sandstone, chert, and mudrocks interbedded with limestone (the Mugagangri Group) [Wen, 1979] most probably represent mélange accreted to a subduction complex [Huang et al, 2017;Li et al, 2017;Zeng et al, 2015]. The Shamuluo Formation, Late Jurassic-Early Cretaceous clastic rocks interlayered with limestones in shallow marine environment, overlies the Mugagangri Group and ophiolite in an angular unconformity contact [Li et al, 2017].…”

Section: Bangong-nujiang Suture Zonementioning

confidence: 99%

“…The Mugagangri Group is exposed along the northern bank of Selingco (Figure 1b). The unit, similar to that in Gaize area [Huang et al, 2017;Li et al, 2017;Zeng et al, 2015], shows blocks-in-matrix structure and contains chaotic blocks of various types. In the Demazong area (Figure 2c), packages of thin-bedded massive sandstone (Sm) may be included as blocks (Figure 4i).…”

Section: Mugagangri Group and Gaaco Formationmentioning

confidence: 99%

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Sedimentary and tectonic evolution of the southern Qiangtang basin: Implications for the Lhasa‐Qiangtang collision timing

et al. 2017

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The Mesozoic stratigraphic record of the southern Qiangtang basin in central Tibet records the evolution and closure of the Bangong‐Nujiang ocean to the south. The Jurassic succession includes Toarcian‐Aalenian shallow‐marine limestones (Quse Formation), Aalenian‐Bajocian feldspatho‐litho‐quartzose to feldspatho‐quartzo‐lithic sandstones (shallow‐marine Sewa Formation and deep‐sea Gaaco Formation), and Bathonian outer platform to shoal limestones (Buqu Formation). This succession is truncated by an angular unconformity, overlain by upper Bathonian to lower Callovian fan‐delta conglomerates and litho‐quartzose to quartzo‐lithic sandstones (Biluoco Formation) and Callovian shoal to outer platform limestones (Suowa Formation). Sandstone petrography coupled with detrital‐zircon U‐Pb and Hf isotope analysis indicate that the Sewa and Gaaco formations contain intermediate to felsic volcanic detritus and youngest detrital zircons (183–170 Ma) with εHf(t) ranging widely from +13 to −25, pointing to continental‐arc provenance from igneous rocks with mixed mantle and continental‐crust contributions. An arc‐trench system thus developed toward the end of the Early Jurassic, with the southern Qiangtang basin representing the fore‐arc basin. Above the angular unconformity, the Biluoco Formation documents a change to dominant sedimentary detritus including old detrital zircons (mainly >500 Ma ages in the lower part of the unit) with age spectra similar to those from Paleozoic strata in the central Qiangtang area. A major tectonic event with intense folding and thrusting thus took place in late Bathonian time (166 ± 1 Ma), when the Qiangtang block collided with another microcontinental block possibly the Lhasa block.

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Section: Interpretation and Discussionmentioning

confidence: 99%

Section: Bangong-nujiang Suture Zonementioning

confidence: 99%

Section: Mugagangri Group and Gaaco Formationmentioning

confidence: 99%

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Sedimentary and tectonic evolution of the southern Qiangtang basin: Implications for the Lhasa‐Qiangtang collision timing

et al. 2017

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“…Previous works have accumulated a large amount of geological data on petrology, isotope geochemistry, geochronology, sedimentary stratigraphy, palaeomagnetism, and seismic geophysical data (Q. Chen, Freymueller, et al, ; J. J. Fan, Li, Wang, & Xie, ; Girardeau et al, ; Haines et al, ; Kapp, Yin, Harrison, & Ding, ; S. Li, Ding, et al, ; D. L. Liu, Shi, Ding, & Zou, ; Mo, ; Pan et al, ; Qiu et al, ; Shi, Yang, Xu, & Qi, ; Qu, ; S. Y. Yu, Zhang, del Real, et al, ; S. Y. Yu, Zhang, Li, et al, ; S. Y. Yu et al, ; K. J. Zhang, Xia, Wang, Li, & Ye, ; Y. X. Zhang, Li, et al, ; X. Z. Zhang, Wang, et al, ; R. S. Zhang & Zeng, ; D. C. Zhu et al, , ).…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Guo

et al. 2019

Geological Journal

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The Bangong–Nujiang Suture Zone (BNSZ) is one of the main suture zones in the Tibetan Plateau and indicates the existence of the Bangong–Nujiang Neo‐Tethys Ocean (BNO). It was formed by the collision between the Qiangtang and Lhasa blocks after the closure of the BNO. However, its evolutionary processes and subduction polarity remain controversial. Research on the BNSZ is of great significance for exploring plate tectonic evolution and ocean–continent connection. The scarcity of the BNSZ structural data is one of the most important reasons for the debate of the BNO tectonic evolution. Based on structural analysis in the field and combined with previous petrology and palaeomagnetic data, this paper has determined that the closure time of the BNO is progressive and scissor‐like, from Middle Jurassic in the east to Early Cretaceous in the middle and late Early Cretaceous to early Late Cretaceous in the west. There was a three‐stage deformation in the BNSZ: (a) N–S‐directed compression induced by the initial collision; (b) WNW–directed transpression related to the stress adjustment; and (c) NE–SW‐directed compression caused by the low‐angle NE‐directed subduction of the Indus–Yarlung Zangbo Ocean. The different structural pattern along the eastern segment of the BNSZ may have resulted from orogenic bending due to the later Himalayan Orocline caused by the India–Eurasia collision in the Cenozoic.

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Geochronology, geochemistry, origin, and tectonic implications of high‐pressure mafic granulites of the Amdo region, Central Tibet

et al. 2020

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The Amdo Terrane, Central Tibet, was previously located in the middle of the Bangong-Nujiang Ocean (BNO), and is key to understanding the subduction history of the BNO. However, the high-pressure (HP) mafic granulites of the Amdo Terrane remain poorly studied. Here, we report the petrology, geochemistry, and zircon U-Pb geochronology of the Amdo HP mafic granulites. The granulites occur mainly as enclaves or deformed dikes in granitic gneisses of the Amdo Terrane. Zircons from the granulites yield two clusters of ages, at 193-192 and 180 Ma. The former represents the best estimate of the age of peak metamorphism, and the latter represents the age of retrograde amphibolite-facies metamorphism. Although the contents of mobile elements in the granulites, including the large-ion lithophile elements (Rb, Sr, Cs, Pb, K), were significantly altered during metamorphism, the contents of the highfield-strength elements (HFSEs; Th, Nb, Zr, Ti) and rare earth elements (REEs) remained largely unchanged. The granulites belong to the tholeiitic basalt series, with SiO 2 contents of 47.05-51.03% and Mg# of 35-50. The REE contents of the granulites are characterised by flat chondrite-normalised patterns (La N /Yb N = 0.96-1.92; La N /Sm N = 1.0-1.59) and weak Eu anomalies (Eu/Eu* = 0.84-0.99). Most of the granulite samples have high TiO 2 contents, clear negative Nb and Ta anomalies, and high Pb enrichment, with positive zircon ε Hf (t) values (+8.14 to +16.02). The granulites exhibit both normal mid-ocean ridge basalt (N-MORB) and island-arc basalt (IAB) characteristics. Using the data presented here and previous data, we suggest that the protolith of the granulites were back-arc basin basalts derived from high-degree partial melting of depleted mantle in the spinel stability field, which records the early evolution of the BNO. Northward subduction of the BNO oceanic plate led to backarc spreading and the formation of back-arc basin basalts on the northern margin of the Amdo Terrane. The back-arc basin extended further to form an ocean basin, which separated the Amdo Terrane and the Southern Qiangtang-Baoshan (SQB) Terrane, resulting in the Amdo Terrane becoming an isolated microcontinent in the BNO.

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The subduction-accretion history of the Bangong-Nujiang Ocean: Constraints from provenance and geochronology of the Mesozoic strata near Gaize, central Tibet

Cited by 93 publications

References 61 publications

Sedimentary and tectonic evolution of the southern Qiangtang basin: Implications for the Lhasa‐Qiangtang collision timing

Sedimentary and tectonic evolution of the southern Qiangtang basin: Implications for the Lhasa‐Qiangtang collision timing

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

Geochronology, geochemistry, origin, and tectonic implications of high‐pressure mafic granulites of the Amdo region, Central Tibet

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