Early Ordovician island‐arc‐type Manite granodiorite pluton from the Buqingshan Tectonic Mélange Belt in the southern margin of the East Kunlun Orogen: constraints on subduction of the Proto‐Tethyan Ocean

Abstract

The Buqingshan Tectonic Mélange Belt in the south margin of the East Kunlun Orogen, located in west section of Buqingshan–A'nyemaqen Suture Zone, is one of the key areas to understand continental tectonics and continental dynamics of China. This paper reports zircon U–Pb dating results and geochemistry of the Manite granodiorite (rock mass) in the Buqingshan Tectonic Mélange Belt. Zircons from the granodiorite show oscillatory zoning structures and relatively high Th/U ratios, indicating that they are magmatic zircons. Zircon LA–ICP–MS U–Pb dating for the Manite granodiorite yields ages of 487 ± 11 Ma (MSWD = 2.3) and 479 ± 2 Ma (MSWD = 0.56), implying that the Manite granodiorite were formed in the Late Cambrian to Early Ordovician. Geochemical analyses show that the rocks have high contents of SiO2 (66.06 wt.%–68.60 wt.%) and Al2O3 (14.84 wt.%–16.54 wt.%), and low alkaline (6.17 wt.%–7.43 wt.%), belonging to the middle‐K calc‐alkaline series. The A/CNK (Al2O3/(CaO + Na2O + K2O)) ratios are 1.02–1.15, indicating that the granodiorite is weakly peraluminous. The contents of rare earth elements (REEs) are lower (89.64–130.41 ppm), with weakly negative to weakly positive Eu anomalies (δEu = 0.83–1.12). The primitive mantle‐normalized trace elements are characterized by evidently negative anomalies of Nb, Ta, P, Hf, Ti, etc., and positive anomalies of Th, La, Nd, Zr, Eu, etc. Moreover, the rocks show features of typical I‐type granite. This leads us to conclude that the Manite granodiorites is derived from the partial melting of crust and formed in an island‐arc environment. Combined with previous studies, we believe that the subduction of the Proto‐Tethyan Ocean in the Buqingshan area was ongoing during 487 to 479 Ma and formed island‐arc‐type granites represented by the Late Cambrian to Early Ordovician Manite granodiorite. Copyright © 2016 John Wiley & Sons, Ltd.

The Sardic Phase: field evidence of Ordovician tectonics in SE Sardinia, Italy

“…During Early Ordovician time, these reconstructions place Sardinia on the eastern side of the northern margin of Gondwana. It was still a convergent setting (Li et al 2016) where the Qaidam Ocean (more or less coincident with the Proto Tethys Ocean according to previous reconstructions, e.g. von Raumer & Stampfli, 2008) was subducting under the South China terrane with SE Sardinia being located close to the convergent margin of the upper plate and, on the basis of our findings, probably somewhat closer to the margin than previously thought (von Raumer & Stampfli, 2008; von Raumer et al 2013).…”

“…2008), Turkey (Okay, Satir & Shang, 2008), South China (Li et al . 2016) and Sardinia (Oggiano et al . 2010; Gaggero et al 2012).…”

Oceanic island basalts in ophiolitic mélanges of theCentralChinaOrogen: An overview

“…The Buqingshan ophiolitic mélange is a northwest part of the Anyemaqen ophiolite belt in the southern East Kunlun marginal suture (Li, Pei et al, ; Yang et al, ; Zhu et al, ; Figure ). The WNW‐trending ophiolitic mélange consists of metaperidotite, gabbro, diabase, pillow basalt, massive basalt, and pelagic sedimentary rocks including radiolarian chert, thick‐massive carbonate rock, and siliceus mudstone (Bian et al, ; Li et al, ).…”

“…The Buqingshan ophiolitic mélange is a northwest part of the Anyemaqen ophiolite belt in the southern East Kunlun marginal suture (Li, Pei et al, 2017;Yang et al, 1996;Zhu et al, 1999;Figure 3…”

Petrogenesis and tectonic implications of the quartz diorites and mafic microgranular enclaves in the Asiha gold ore deposit in the East Kunlun orogenic belt: Evidence from zircon U–Pb dating, geochemistry, and Sr–Nd–Hf isotopes

“…The granite‐MME associations have been widely documented in many complexes from Middle Permian to Late Triassic: the Naomuhun granodiorites and their MMEs (Xiong et al, 2012), the Qianwadaqiao granodiorites and their MMEs (G. C. Chen, Pei, Li, Li, Pei, et al, 2018), the Qushi'ang granodiorites and their MMEs (G. C. Chen, Pei, Li, Li, Liu, Chen, et al, 2017), the Harizha granodiorites and their MMEs (Xin et al, 2019), the Saishitang granodiorites and their MMEs (J. Y. Zhang, Yang, et al, 2017), and the Xiangride porphyritic granodiorites and their MMEs (Xiong, Ma, Zhang, Liu, & Jiang, 2014). The EKOB in the Qinghai‐Tibetan Plateau is considered to undergo multi‐stages of tectonic‐magmatic evolution (Y. X. Chen, Pei, Li, Li, Liu, & Wang, 2017; Y. P. Dong et al, 2018; Du et al, 2017; J. J. Kong, Niu, He, Zhang, & Shao, 2020; Z. C. Li, Pei, et al, 2017; Y. G. Liu et al, 2018, 2019; X. Xu et al, 2020; Z. W. Zhang et al, 2018; M. J. Zhang et al, 2021). The evolutionary history of the Palaeo‐Tethys within the EKOB has attracted considerable attention over the past decades (Y. P. Dong et al, 2018; Gao & Sun, 2021; Hu et al, 2016; Huang et al, 2014; J. J. Kong et al, 2020; H. L. Kong et al, 2021; Y. Y. Liang, Xia, Ma, Zhao, & Guo, 2020; Richards, 2015; Shao et al, 2017; Song et al, 2020; Tian et al, 2021; J. Y. Zhang, Ma, Xiong, & Liu, 2012; Zhao et al, 2019).…”