Reply to comment by L.Z. Shi et al. on “Birth and demise of the Bangong–Nujiang Tethyan Ocean: A review from the Gerze area of central Tibet”

Li, Shun; Yin, Changqing; Guilmette, Carl; Ding, Lin

doi:10.1016/j.earscirev.2020.103213

Cited by 5 publications

(1 citation statement)

References 30 publications

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“…Rutog and Dongco ophiolites (Wang et al, 2016) were used to represent mantle-derived magma (( 87 Sr/ 86 Sr) t = 0.7033-0.7063, ε Nd (t) = + 8.1 − + 5.4). The Rena Co two-mica granite (Hu et al, 2017) (Li et al, 2019;Li, Yin, Guilmette, & Ding, 2020;Zhu et al, 2016). At ca.…”

Section: Tectonic Implicationsmentioning

confidence: 99%

Zircon U–Pb ages, geochemistry, and Sr–Nd–Pb–Hf isotopes of the Mugagangri monzogranite in the southern Qiangtang of Tibet, western China: Implications for the evolution of the Bangong Co‐Nujiang Meso‐Tethyan Ocean

et al. 2021

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We present in‐situ zircon laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) U–Pb ages, whole‐rock geochemistry, and Sr–Nd–Pb–Hf isotopes of the Mugagangri monzogranite in the southern margin of the Qiangtang Block, Tibet, western China. The zircons yield a U–Pb age of ca. 123 Ma. The hornblende‐bearing monzogranite shows metaluminous to weak peraluminous and high‐K calc‐alkaline characteristics exemplified by high silica (SiO2 = 67.57–70.57 wt%), high aluminium (Al2O3 = 14.68–15.78 wt%), high potassium (K2O = 4.00–5.14 wt%), high alkali (K2O + Na2O = 7.88–8.62 wt%), and low calcium contents (CaO = 1.72–2.17 wt%), with the aluminium saturation index (A/CNK) ranging from 0.98 to 1.09, suggesting that the Mugagangri monzogranite is a metaluminous to weak peraluminous I‐type high‐K calc‐alkaline granite. Geochemically, similar to the arc magmas, the monzogranite is enriched in large‐ion lithophile elements, and relatively depleted in high‐field‐strength elements. The monzogranite displays relatively high (87Sr/86Sr)i values (0.70972–0.71240), uniform εNd(t) values (−2.24 to −3.40), variable zircon εHf(t) values (−14.1 to +8.0), and high radiogenic Pb isotopic values (206Pb/204Pb = 18.588–18.790, 207Pb/204Pb = 15.616–15.642, and 208Pb/204Pb = 38.838–39.053). These geochemical characteristics indicate that the monzogranite was derived from a mixed source comprising ancient crustal and mantle materials, and experienced fractional crystallization during emplacement. We propose that the parental magma of the Mugagangri monzogranite was most likely generated during northward subduction of the Bangong Co‐Nujiang Meso‐Tethys Ocean.

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Section: Tectonic Implicationsmentioning

confidence: 99%

Zircon U–Pb ages, geochemistry, and Sr–Nd–Pb–Hf isotopes of the Mugagangri monzogranite in the southern Qiangtang of Tibet, western China: Implications for the evolution of the Bangong Co‐Nujiang Meso‐Tethyan Ocean

et al. 2021

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Resolving the timing of Lhasa-Qiangtang block collision: Evidence from the Lower Cretaceous Duoni Formation in the Baingoin foreland basin

Zhu

Zhai

et al. 2022

Palaeogeography, Palaeoclimatology, Palaeoecology

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Petrogenesis and Geodynamic Implications of Early Cretaceous (∼130 Ma) Magmatism in the Baingoin Batholith, Central Tibet: Products of Subducting Slab Rollback

Tang

Wang

et al. 2022

Acta Geologica Sinica (Eng)

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The Baingoin batholith is one of the largest granitic plutons in the North Lhasa terrane. Its petrogenesis and tectonic setting have been studied for decades, but remain controversial. Here we report data on geochronology, geochemistry and isotopes of Early Cretaceous granitoids within the Baingoin batholith, which provide more evidence to uncover its petrogenesis and regional geodynamic processes. The Early Cretaceous magmatism yields ages of 134.4–132.0 Ma and can be divided into I‐type, S‐type and highly fractionated granites. The I‐ and S‐type granites exhibit medium SiO2, high K2O/Na2O with negative εNd(t) and εHf(t) values, whereas, the albite granites have very high SiO2 (79.04%–80.40%), very low K2O/N2O, negative εNd(t) and a large variation in εHf(t). Our new data indicate that these granitoids are derived from unbalanced melting in a heterogeneous source area. The granodiorites involved had a hybrid origin from partial melting of basalt‐derived and Al‐rich rocks in the crust, the porphyritic monzogranites being derived from partial melting of pelitic rocks. The albite granites crystallized from residual melt separated from K‐rich magma within the ‘mush’ process and underwent fractionation of K‐feldspar. We believe that the Early Cretaceous magmatism formed in an extensional setting produced by the initial and continuous rollback of a northward‐subducting slab of the NTO.

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Reply to comment by L.Z. Shi et al. on “Birth and demise of the Bangong–Nujiang Tethyan Ocean: A review from the Gerze area of central Tibet”

Cited by 5 publications

References 30 publications

Zircon U–Pb ages, geochemistry, and Sr–Nd–Pb–Hf isotopes of the Mugagangri monzogranite in the southern Qiangtang of Tibet, western China: Implications for the evolution of the Bangong Co‐Nujiang Meso‐Tethyan Ocean

Zircon U–Pb ages, geochemistry, and Sr–Nd–Pb–Hf isotopes of the Mugagangri monzogranite in the southern Qiangtang of Tibet, western China: Implications for the evolution of the Bangong Co‐Nujiang Meso‐Tethyan Ocean

Resolving the timing of Lhasa-Qiangtang block collision: Evidence from the Lower Cretaceous Duoni Formation in the Baingoin foreland basin

Petrogenesis and Geodynamic Implications of Early Cretaceous (∼130 Ma) Magmatism in the Baingoin Batholith, Central Tibet: Products of Subducting Slab Rollback

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