Rushan-Pshart Paleo-Tethyan Suture Deduced from Geochronological, Geochemical, and Sr-Nd-Hf Isotopic Characteristics of Granitoids in Pamir

Lithos 364–365 (2020) 105549

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Research Article Rushan-Pshart Paleo-Tethyan suture deduced from geochronological, geochemical, and Sr-Nd-Hf isotopic characteristics of granitoids in Pamir

Shifeng Wang a,WenkunTanga,⁎, Yiduo Liu b, Xinghong Liu a, Xin Yao a a Key Laboratory of Paleomagnetism and Tectonic Reconstruction, Ministry of Land and Resources, Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China b Department of Earth and Atmospheric Sciences, University of Houston, TX 77204, USA article info abstract

Article history: Correlation of blocks comprising the Pamir plateau with blocks in the Tibetan plateau is debated due to the com- Received 24 September 2019 plex tectonic history of amalgamated orogenic belts, followed by widespread Cenozoic intracontinental deforma- Received in revised form 20 April 2020 tion within the Pamir plateau. Of particular interest is the Rushan-Pshart suture along the southern edge of the Accepted 21 April 2020 Central Pamir. It is uncertain if the suture zone is a Meso-Tethyan or a Paleo-Tethyan suture and if it is the west- Available online 25 April 2020 ern extension of the Bangong-Nujiang suture. This study presents new in-situ zircon U-Pb geochronology, whole-

Keywords: rock geochemistry, and Sr-Nd-Hf isotopes of three granitic plutons (Tahman, Tash, and Mingtie) along the south- Central Pamir block ern edge of the Central Pamir block. Emplacement ages of the three plutons range from ~206 Ma to ~201 Ma. Rushan–Pshart Paleo-Tethyan Suture Samples from Tahman and Tash contain 67% to 76% SiO2, and yield A/CNK values between 0.92 and 1.17. They Indosinian granite exhibit high LILE/HFSE ratios, negative Eu anomalies (Eu/Eu* = 0.41–0.77), pronounced negative Nb, Ta, P, and Zircon U-Pb age Ti anomalies, negative εNd(t) values (between −7.3 and −6.9), and negative zircon εHf(t) values (between Geochemistry −15.5 and −1.4). Geochemical data indicate that the Tahman and Tash samples represent metaluminous or peraluminous, I-type arc-related granitoids. The Tahman granites are inferred to have formed by partial melting of the Precambrian metaigneous and metasedimentary rocks in the lower crust, while the Tash pluton was formed by partial melting of the infracrustal medium-to-high K basaltic compositions within the garnet stability ﬁeld of the lowermost crust. We suggest that these newly discovered Late Triassic granite plutons are related to the closure of the Rushan-Pshart suture. This is supported by recent geochronological, paleontological, and stratigraphic studies. Thus, the Rushan-Pshart suture is a Paleo-Tethyan suture. We further notice that the Central Pamir block is bounded by the Tanymas and Rushan-Pshart Paleo-Tethyan sutures to the north and south, respectively, which is structurally similar to the North Qiangtang and the Indochina blocks that are also bounded by two Paleo-Tethyan sutures from both sides. This indicates that the Central Pamir block is the western extension of the Tianshuihai-North Qiangtang block, both of which underwent oblique convergence during the closure of the Paleo-Tethys ocean. © 2020 Elsevier B.V. All rights reserved.

1. Introduction Late Cretaceous), and Neo-Tethys (Late Triassic–Late Cretaceous) (Metcalfe, 2013; Robinson, 2015; Sengör, 1984; Xiao et al., 2002, The Himalayan–Tibetan–Pamir orogenic plateau witnessed the se- 2005; Zhang et al., 2018a). Some blocks, such as the Cimmerian block quential accretion of blocks onto the southern margin of Eurasia since (which includes the Turkey, Iran, Afghan, Qiangtang, Baoshan, and the Neo-Proterozoic (e.g., Robinson, 2015; Yin and Harrison, 2000). In Sibumasu micro-blocks), extend over a distance of N7000 km from the the Tibet Plateau, from north to south, these blocks include: the Mediterranean Sea in the west to the Sumatra arc in the east (Fig. 1a). Qaidam-Kunlun, Songpan-Ganzi, Qiangtang, Lhasa, and Himalayan Due to the complex tectonic history of the amalgamated orogenic blocks. In the Pamir plateau, similarly, there exist the North, Central, belts, as well as subsequent widespread Cenozoic intracontinental de- and South Pamir blocks (Fig. 1a). Rifting and drifting of these blocks formation, correlation of the blocks comprising the Pamir plateau with from Gondwana and their subsequent accretion onto Eurasia are gener- those in Tibetan plateau remains unresolved. In particular, intense ally related to the successive opening and closing of four intervening strain localized at the western Himalayan syntaxis in the Pamir region oceans, namely, the Proto-Tethys (Neo-Proterozoic–Ordovician), during the Cenozoic has resulted in discussion on whether the South Paleo-Tethys (Devonian–Triassic), Meso-Tethys (late Early Permian– or Central Pamir is the western continuation of the Qiangtang block, and whether the Rushan-Pshart Suture (RPS) corresponds to the – ⁎ Corresponding author. Bangong Nujiang suture (BNS) (Fig. 1a) (e.g. Angiolini et al., 2013; E-mail address: [email protected] (W. Tang). Lacassin et al., 2004; Schwab et al., 2004).

Fig. 1. Simpliﬁed geologic map of the eastern Pamir (after Xinjiang BGMR, 2005), part of geochronological data in the study area also shown. Abbreviations: ① - Caledonian granite belt; ② - Indosinian granite belt; ③ - Yanshanian granite belt; TSH-NQ-Tianshuihai-North Qiangtang; SQ-south Qiangtang; SC-South China; NC -North China; SG- Songpan-Ganzi; L = Lhasa;JS- Jinshajiang suture; LSS- Longmu Co-Shuanghu suture; BNS- Bangong-Nujiang suture; YS- Yalong–Indus suture; TS- Tanymas suture; KS- Kudi suture; RPS- Rushan-Pshart suture; ShS- Shyok suture; CMS- Changning-Menglian suture; ATF: Altyn Tagh fault; KKF: Karakorum fault; Tash. F-Tashikurgan fault. S. Wang et al. / Lithos 364–365 (2020) 105549 3

Recent petrological, geochronological, and geochemical studies on to the west of Tashkurghan town yields a zircon U–Pb age of 12–8Ma ophiolitic, magmatic, and metamorphic rocks in central Qiangtang (Jiang et al., 2012), and a granite intruded into the Bulunkuole have shown that the Longmu Co–Shuanghu Suture represents a primary Palaeoproterozoic gneiss yields an age of 855 ± 14 Ma (Bian et al., Paleo-Tethyan suture (Li et al., 2006, 2009; Li et al., 2019; Wang et al., 2013). Three magmatic belts developed in the eastern Pamir, which 2018, 2019; Zhai et al., 2011, 2013, 2016). The North Qiangtang block are, from north to south, the Cambro-Ordovician, Permo-Triassic, and is interpreted as having a Cathaysian affinity, whereas the South Jurassic-Cretaceous magmatic belts (Bi et al., 1999; Kang et al., 2012, Qiangtang block is ascribed to represent the eastern segment of the Cim- 2015; Li et al., 2016; Schwab et al., 2004; Zhang et al., 2005). Based on merian block (Li et al., 2006, 2009; Li et al., 2019; Metcalfe, 2013; Wang geochronological and geochemical characteristics of the granites, these et al., 2016b, 2018, 2019). On the west side of the Karakorum Fault magmatic belts are considered to be associated with the closure of the (KKF), the Rushan-Pshart suture has been conventionally interpreted Kudi Proto-Tethys, Jinshajiang (Tanymas) Paleo-Tethys, and Bangong- as a Meso-Tethyan suture that correlates with the Bangong-Nujiang Nujiang (Rushan-Pashart or Shyok) Meso-Tethys oceans, respectively Meso-Tethyan suture (Burtman and Molnar, 1993; Lacassin et al., (Mattern and Schneider, 2000; Xiao et al., 2002, 2005; Zhang et al., 2004; Schwab et al., 2004). However, recent studies proposed alterna- 2004, 2016, 2018a, b; Li et al., 2007a; Qu et al., 2007; Yang et al., 2010). tively that the Rushan-Pshart suture is a Paleo-Tethyan suture rather Although no ophiolitic rocks have been identified, the presence of than a Meso-Tethyan one, based on new studies on biostratigraphy, the Longmu Co–Shuanghu suture in the southern part of the study mafic dikes, and granites in Central Pamir (Angiolini et al., 2013; area is inferred from the juxtaposition of Cathaysian- and Chapman et al., 2018; Hong et al., 2017). These competing interpreta- Gondwanan-affinitive biostratigraphy (Fig. 1). The strata to the north tions of the tectonic architecture in Pamir highlight the uncertainties of the Longmu Co-Shuanghu Suture is comprised of Upper Devonian in block correlation between Pamir and Tibet. Therefore, more research to Lower Permian sandstone and shale that contain warm-water is needed to document the evolution of the Rushan-Pshart suture and its Cathaysian fossil assemblages, similar to those observed in the North relationship to the sutures in the Tibetan Plateau. Qiangtang area; in contrast, Upper Devonian to Lower Permian units Geochronological and geochemical data from granitic rocks can pro- to the south of the Longmu Co Suture are characterized by cold-water vide important information regarding the timing and nature during sub- assemblages of Gondwanan affinity (Huang, 2001; Bureau of Geology duction and collision of plate convergence. In Pamir, the emplacement of and Mineral Resources of Xinjiang Uygur Autonomous Region the Caledonian granite belt is related to the closure of the Kudi Proto- (Xinjiang BGMR), 2006; Cui et al., 2006; Xia et al., 2006; Li et al., 2006, Tethys, the emplacement of the Indosinian granite belt to the closure of 2009; Metcalfe, 2013). Thus, the Tianshuihai-North Qiangtang block is the Jinshajiang Paleo-Tethys, and the emplacement of the Yanshanian bounded by the Jinshajiang suture to the north and the Longmu Co- granite belt to the closure of the Bangong-Nujiang Meso-Tethys oceans Shuanghu suture to the south, both of which are in the Paleo-Tethyan (e.g. Jiang et al., 2002, 2013; Xiao et al., 2002, 2005; Schwab et al., 2004; domain. The magmatic records around Mazar also support this double Zhang et al., 2004, 2005, 2016, 2018a,b;Fig. 1b). In this contribution, Paleo-Tethyan suture model (Liu et al., 2015). Along the west side of we present new geochronological and geochemical data from the the KKF in the eastern Pamir, there exist the Tanymas, Rushan-Pshart, Indosinian granitic plutons in the eastern Pamir to better understand and Shyok sutures from north to south. While the Tanymas and Shyok the spatiotemporal evolution of the Rushan-Pshart suture. Based on the sutures are of the Paleo- and Meso-Tethyan domains, respectively, the newly obtained and previously published data, we attempt to correlate nature of the Rushan-Pshart suture is unclear (Angiolini et al., 2013; the sutures and micro-blocks in Pamir with those in the Tibetan Plateau. Chapman et al., 2018; Lacassin et al., 2004; Schwab et al., 2004). Many faults are observed within the study area, including, from west 2. Geological setting to east, the Aksu–Rangkul, Tashkurghan, Kongur, Xindi–Kuke, Waqia, and Kumtag (a branch of the Kashgan–Yecheng transfer zone) faults The study area is located along the southern edge of the Central (Sobel et al., 2011; Strecker et al., 1995)(Fig. 1). The Tashkurghan Pamir block in eastern Pamir, separated from the Tianshuihai-North Fault represents the northern segment of the KKF and bounds the Qiangtang block by the KKF on the east side (Fig. 1). north–trending Tashkurghan Basin in the study area. Tectonostratigraphic units exposed in the study area mainly consist of Palaeoproterozoic gneiss of the Bulunkuole Group, Lower Silurian slate 3. Petrographic characteristics of the Indosinian granites and marble interbedded with andesite and basalt, Upper Carboniferous limestone, and Middle Permian basalt, sandstone, slate, and limestone The Tahman granitic pluton crops out over an area of 25 km2 and in- (Bureau of Geology and Mineral Resources of Xinjiang Uygur truded the gneiss of the Bulunkuole group. It has no detectable deforma- Autonomous Region (Xinjiang BGMR), 2006 (Fig. 1). These units are ex- tion or metamorphism. Seven samples were collected from the Tahman tensively deformed and are typically in fault contact with each other. pluton which is medium-coarse grained, greyish-white in colour, and The Bulunkuole Group represents the basement of the Tianshuihai- has a massive structure (Fig. 2a, c, d). All samples are monzonitic gran- North Qiangtang, North Pamir and Central Pamir blocks. Published geo- ites that are composed of K-feldspar (~25–35 vol%), plagioclase (~20–25 chronological data indicated that the Bulunkuole Group underwent a vol%), quartz (~20–30 vol%), biotite (~8–15 vol%), with minor zircon, complex evolution and is subdivided into several formations. A apatite, titanite and iron oxides. biotite-hornblende gneiss is dated at 2481 ± 14 Ma (zircon U–Pb We observed a 300–500-m-thick ductile shear zone that transects age), and sillimanite-, garnet-, and hornblende-bearing gneisses yield the widespread magmatic area west of the Tashkurgan basin. The zircon U–Pb protolith and metamorphic ages of 540 and 250–220 Ma, northwest-striking shear zone extends about 60–80 km long in China respectively (Ji et al., 2010; Qu et al., 2007; Yang et al., 2010; Zhang and continues into Tajikistan to the northwest (Fig. 1). This shear zone et al., 2005, 2018a). Mesozoic strata are rare in the study area, which is referred to as the Aksu–Rangkul Fault and is interpreted to represent are mainly comprised of Jurassic marble, volcaniclastic rocks, and Creta- a branch of the KKF (Strecker et al., 1995). The main body of the Tash ceous clastic sedimentary rocks. Due to limited access in Pamir, the pluton intruded into the Silurian slate with the Aksu–Rangkul Fault im- strata in both Central Pamir and Tianshuihai-North Qiangtang block posed on it. Along its eastern end, Quaternary fluvial fans cover its sur- have been attributed to the same stratigraphic system (Xinjiang face trace. The Tash pluton outcrop is about 12–15 km long and 4–5km BGMR, 2005). A minor amount of strata, mainly Permian limestone wide. We collected eight undeformed granitic samples (BL7–1to with cold water floras of the South Qiangtang block affinity, is also ex- BL7–8) for geochronologic and geochemical analyses. The eight samples posed in the study area. are generally greyish-white and fine-to- medium-grained. The samples Magmatic rocks are widespread in the eastern Pamir, with a wide are classified as granodiorite based on microscopic observation (Fig. 2e). range of ages from the Proterozoic to the Cenozoic. A granitic complex They are dominated by euhedral to subhedral plagioclase (25–35 vol%), 4 S. Wang et al. / Lithos 364–365 (2020) 105549

Fig. 2. Indosinian granitic plutons. 2a- Deformed Mingtie granitic pluton; 2b-Undeformed Tahman granitic pluton; 2c- S–C foliations in Mingtie pluton shown by plagioclase phenocryst and mylonitic mica ribbons; 2d, 2f- undeformed granite from Tahman and Tash plutons. Abbreviations: Qtz- quartz; Pl- plagioclase; Kfs- potash-feldspar; Bt- biotite; Zr- zircon.

K-feldspar (20–25 vol%), quartz (20–25 vol%), biotite (5–12 vol%), and techniques. Pure zircon grains were selected using a binocular micro- hornblende (4–8 vol%), with accessory minerals including apatite, zir- scope. Representative grains were placed into an epoxy resin and con, magnetite, and titanite. ground down by about half to expose the zircon interior, before U-Pb We also collected three samples (BL6–7, MT-1, −2) from the dating. Before and after the dating, zircon grains were examined and Mingtie pluton for zircon U-Pb geochronology. Since the samples are photographed in transmitted and reflected light under the polarized mi- all granitic mylonites (Figs.2b, 2f), we did not conduct geochemical croscope, together with cathodoluminescence images (CL), in order to analysis on these samples. The Mingtie pluton is about 9–11 km long determine the crystalline shape, inner structure and dating position. and 2–4 km wide. The Mingtie pluton is in fault contact with Devonian Zircon U–Pb dating was undertaken using a New Wave UP193FX limestone at its eastern side and is intruded by the Yanshanian granite Excimer LA system coupled with an Agilent 7500a ICP–MS instrument, plutons around it. Samples from the pluton are all augen granitic at the Key Laboratory of Continental Collision and Plateau Uplift, Insti- mylonites, the samples are composed of quartz (5–10 vol%), plagioclase tute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), (25–30 vol%), biotite (10–15 vol%), K-feldspar (5–10 vol%), as well as a Beijing, China. These analyses used a 36 μm diameter laser beam and a felsic matrix (35–40 vol%) and accessory minerals including chlorite, 45 s ablation time. Helium was used as the carrier gas within the abla- magnetite, epidote, apatite, and zircon. tion cell to enhance the transport efficiency of the ablated materials. Raw count rates for 29Si, 204Pb, 206Pb, 207Pb, 208Pb, 232Th, and 238U 4. Analytical methods were collected for age determinations, with U, Th, and Pb concentrations as well as the concentrations of some other selected trace ele- Nine granite samples from three plutons south of the Bulunkou In- ments being calibrated using 29Si as an internal standard and a NIST dochina granite belt were prepared for zircon U-Pb LA-ICP-MS dating. SRM 610 silicate glass standard as reference material. 207Pb/206Pb, Zircons were separated using conventional heavy-liquid and magnetic 206Pb/238U, 207Pb/235U, and 208Pb/232Th isotopic ratios and age estimates S. Wang et al. / Lithos 364–365 (2020) 105549 5 were calculated using the Macquarie University GLITTER 4.0 program 80–100 μm wide. We selected 25 representative zircon grains for U– and were corrected using a 91,500 zircon as an external standard. Pb dating (Table 1 in Appendix). Most grains yield Th/U ratios of Weighted average age calculations and concordia diagram construction 0.18–0.91, consistent with a magmatic origin. The U-Pb results are typ- were undertaken using Isoplot/Ex version 3.0 (Ludwig, 2003). Age cal- ically well clustered and can be used to determine weighted mean culations were based on U decay constants of 235U = 9.8454 × 10−10 206Pb/238U ages. Samples BL3–1, BL3–2, and BL3–3 yield ages of 206.2 per annum and 238U = 1.55125 × 10−10 per annum (Ludwig, 2003), ± 1.4 Ma (95% confidence (same below), MSWD = 0.3), 206.0 ± 1.4 and common Pb corrections were made using the approach of Ma (MSWD = 0.1), and 205.3 ± 1.9 Ma (MSWD = 0.3), respectively Andersen (2002). (Fig. 3a–c). We interpret these ages as the timing of crystallization of In situ zircon Lu–Hf isotopic analyses were conducted using a New the Tahman granitic complex. Wave UP213 LA system coupled with a Neptune multicollector (MC)– Zircon grains from three samples of the Mingtie pluton (BL6–7, MT- ICP–MS instrument at the State Key Laboratory for Mineral Deposits 1, and MT-2) are typically light yellow to transparent, euhedral, and Research, Nanjing University, China. The in situ zircon LA–ICP–MS Hf iso- prismatic. They are generally 70–140 μm long and 40–70 μm wide. CL topic analysis used a beam size of 60 μm and a laser pulse frequency of 8 images reveal luminescent (low-U) cores and euhedral fine-scale oscil- Hz. Details of the analytical approaches used and the methods used to latory igneous zoning. We selected 25 representative grains for U–Pb correct for the interference of 176Yb on 176Hf are given in Hou et al. dating (Table 1 in Appendix). Th/U ratios mainly range from 0.10 to (2007).A176Lu decay constant of 1.865 × 10−11/year was used to calcu- 0.65 while some spots yield 0.03–0.09 Th/U ratios, suggesting a mag- late initial 176Hf/177Hf ratios, and the chondritic values of 176Lu/177Hf = matic origin. The results are generally well clustered and are used to cal- 0.0332 and 176Hf/177Hf = 0.282772 reported by Blichert-Toft and culate the weighted mean 206Pb/238U ages (Fig. 3d–f). Samples BL6–7, Albarede (1997) were used to calculate εHf(t) values. Single-stage MT-1, and MT-2 yield ages of 204.2 ± 0.6 Ma (MSWD = 0.1), 200.9 ± model ages (TDM1) were calculated using a depleted mantle reservoir 0.6 Ma (MSWD = 1.3), and 200.6 ± 0.5 Ma (MSWD = 0.5), respec- with a present-day 176Hf/177Hf value of 0.28325 and a 176Lu/177Hf value tively. We therefore interpret the Mingtie pluton to be emplaced around of 0.0384, whereas two-stage Hf model ages (TDM2) were calculated 204 Ma. Inherited zircon grains are also observed in the analyzed sam- using a 176Lu/177Hf value of 0.015 for the average continental crust ples (Table 1 in Appendix) and yield ages ranging from 2183 to 254 Ma. (Griffinetal.,2000). A GJ-1 standard zircon was used for external stan- Zircon grains from three samples (BL7–1, −2, −3) of the Tash plu- dardization. εHf(t) values were calculated using a decay constant of ton are typically light yellow to transparent, euhedral, and prismatic. 176Lu of 1.865 × 10−11/year, and all individual Hf isotopic analyses were CL images reveal luminescent (low U) cores and euhedral fine-scale os- located within previously ablated U–Pb analysis pits. cillatory igneous zoning. They are generally 50–160 μm long and 40–80 Fifteen granite samples were chosen for whole-rock major, trace and μm wide. We selected 25 representative zircons for U–Pb dating rare earth element analysis. Prior to analyses, these samples were pow- (Table 1 in Appendix). Similarly, their Th/U ratios mainly range from dered to b20 μm in size using an agate mill. Major element analyses 0.10 to 0.65, several spots yield 0.03–0.09 Th/U ratios, consistent with were undertaken at the Institute of Geology and Geophysics, Chinese a magmatic origin. The results are generally well clustered and are Academy of Sciences (CAS), using a Phillips PW XRF-2400 X-ray fluores- used to calculate weighted mean 206Pb/238Uages(Fig. 3g–j). The sam- cence spectrometer, yielding an analytical uncertainty of b5% (±1σ). ples yield three ages, 206.6 ± 0.6 Ma (MSWD = 0.2), 204.2 ± 0.5 Ma Accuracy and precision of the data were assessed using the international (MSWD = 0.1), and 203.5 ± 0.5 Ma (MSWD = 0.2), respectively. We standard reference materials GSR-3. The related data are presented in infer that the Tash pluton crystallized at ~202 Ma. Inherited zircon Appendix Table 3. Trace element concentrations, including those of grains exist in the eight samples (Table 1 in Appendix) and yield the the rare earth elements (REEs), were determined using solution ICP– ages of 830–502 Ma. MS at the Institute of Tibetan Plateau Research, CAS. Analytical results for the standard sample of AGV-2 are also presented in the Appendix 5.2. Zircon Lu–Hf isotopic analysis Table 3. Details of the operating conditions for the ICP–MS instrument and the data reduction approaches used are given in Liu et al. (2008) We selected two samples (BL3–2, BL3–4) from the Tahman pluton with b5% uncertainties on all trace element concentrations. and three samples (BL7–1, BL7–2, and BL7–3) from the Tash pluton Whole-rock Rb–Sr and Sm–Nd isotopic analyses were undertaken for in situ zircon Lu–Hf isotopic analysis and analyzed ~15 spots for using a Triton thermal ionization magnetic sector mass spectrometer each sample. The results are listed in Fig. 4 and Table 2 in the Appendix. at the School of Earth and Space Sciences, University of Science and Thirty analyses of zircon grains from the Tahman pluton yield initial 176 177 Technology of China, Hefei, China, following the procedures outlined Hf/ Hf ratios of 0.282397–0.282606 and εHf(t) values of −8.7 to by Chen et al. (2007). Mass fractionation corrections for Sr and Nd isoto- −1.4. Their Hf crustal two-stage model ages (TDM2) fall between 1795 pic ratios were based on 86Sr/88Sr = 0.1194 and 146Nd/144Nd = 0.7219. and 1329 Ma, with a mean of 1624 Ma. Repeated measurements of La Jolla and NBS987 Sr standard Forty-five analyses of zircon grains from the Tash pluton yield initial 176 177 solutions gave mean values of 0.511869 ± 0.000006 (2σ, n =25) Hf/ Hf ratios of 0.282211–0.282453 and εHf(t) values of −15.2 to 143 144 for the Nd/ Nd ratio and 0.710249 ± 0.000012 (2σ, n = 38) for −5.2. The corresponding Hf crustal two-stage model ages (TDM2) the 87Sr/86Sr ratio. Results of repeated Rb-Sr and Sm-Nd analyses on range from 2223 to 1681 Ma, with a mean of 1958 Ma. the standard material BCR-1 (basalt powder) gave a mean value of 87Sr/86Sr ratio of 0.705027 ± 0.000013 (n = 36; Rb 46.54 ppm, Sr 5.3. Whole-rock major, trace and rare earth element data 329.5 ppm) and a mean value of 143Nd/144Nd ratio of 0.512633 ± 0.000007 (n = 45, Sm 6.676 ppm, Nd 28.77 ppm). Eight samples from the Tahman plutons (BL3–1, −2, −3, −4, −5, −6, −7, −8) and seven samples from the Tash pluton (BL7–1, −2, 5. Results −3, −4, −5, −6, −7) were collected for whole-rock major, trace, and rare earth element (REE) analysis (Table 3 in Appendix). 5.1. Zircon U–Pb data The BL3 series samples from the Tahman pluton are compositionally

homogeneous, with SiO2 = 70.56–75.12 wt%, total alkalis (K2O+Na2O) Zircons from three samples of the Tahman pluton (BL3–1, −2, −4) =7.59–9.02 wt%, CaO = 1.14–1.74 wt%, Al2O3 =12.88–14.76 wt%, were analyzed. The zircon grains are typically light yellow to transpar- MgO = 0.13–0.52 wt%, Fe2O3 =1.78–3.00 wt%, and TiO2 =0.13–0.24 ent, euhedral, and prismatic. Cathodoluminescence (CL) images reveal wt%, respectively. As seen in the (K2O+Na2O) vs. SiO2 diagram the presence of luminescent (low U) cores and euhedral fine-scale oscil- (Fig. 5a) (Middlemost, 1994), all the BL3 series samples fall into the latory igneous zoning. The grains are generally 130–180 μm long and granite field and BL7 series samples fall into the granodiorite field. All 6 S. Wang et al. / Lithos 364–365 (2020) 105549

Fig. 3. Concordia diagram of zircon LA-ICPMS U–Pb dating for Indosinian plutons. MSWD: mean square of weighted deviation.

the Tahman samples (BL3 series) have similar SiO2,Na2O+K2O, and and McDonough, 1989) rare earth and trace element plots. All rocks Al2O3 contents. In the K2O vs. SiO2 and A/NK vs. A/CNK diagrams show enriched light rare earth element (LREE) and flat heavy rare (Fig. 5b, c) (Maniar and Piccoli, 1989; Peccerillo and Taylor, 1976), all earth element (HREE) chondrite-normalized REE patterns (Fig. 6). The these samples fall into the metaluminous high-K calc-alkaline field. In LREE/HREE ratio is between 9.8 and 13.5 in the Tash pluton, and be- the (Na2O+K2O) vs. (Zr + Nb + Ce + Y) diagram (Fig. 5d; Whalen tween 6.77 and 10.86 in the Tahman pluton. The LaN/YbN ratio ranges et al., 1987), these samples are classified as I-type granites. from 12.6 to 19.2 in the Tash Complex and from 6.2 to 11.6 in the

The BL7 series samples from the Tash pluton contain SiO2 = Tahman Complex. Negative Eu anomalies are observed, with Eu/Eu* 66.70–72.30 wt%, total alkalis (K2O + Na2O) = 6.25–7.59 wt%, CaO values ranging from 0.54 to 0.77 in the Tash pluton and from 0.41 to

=1.30–3.37 wt%, Al2O3 = 15.36–15.51 wt%, MgO = 0.54–1.62 wt%, 0.57 in the Tahman pluton. The samples are also marked by variable en- Fe2O3 =1.76–3.66 wt%, and TiO2 =0.22–0.54 wt%. Similar to richments in large ion lithophile elements (LILEs; e.g., Rb, U, and Th) and the Tahman samples, all the Tash samples (BL7 series) show similar depletions in high ﬁeld strength elements (HFSEs; e.g., Ta, Nb, P, and Ti)

SiO2,Na2O+K2O, and Al2O3 contents. In the K2O vs. SiO2 and A/NK (Fig. 6). In the Rb vs. (Yb + Ta) tectonic discrimination diagrams vs. A/CNK diagrams (Fig. 5b, c) (Maniar and Piccoli, 1989; Peccerillo (Pearce, 1996), the granitic rocks fall into the overlapped field of volca- and Taylor, 1976), these samples all fall into the peraluminous high-K nic arc granite and post-collision granite (Fig. 7a), but in the Hf–Rb–Ta calc-alkaline field. Furthermore, in the (Na2O+K2O) vs. (Zr + Nb + tectonic classification diagrams (Fig. 7b) (Harris et al., 1986), they Ce + Y) diagram (Fig. 5d; Whalen et al., 1987), they can also be classi- largely fall into the volcanic arc granite field and far away from the fied as I-type granites. post-collision granite field. Overall, the whole-rock major, trace and The granitic samples from the two plutons display similar patterns in rare earth element compositions of the 15 granites from the two plutons the chondrite- (Boynton, 1984) and primitive mantle-normalized (Sun are characteristic I-type, arc-like granites. S. Wang et al. / Lithos 364–365 (2020) 105549 7

Fig. 4. εHf(t) vs. U–Pb ages for granites of the Tahman, Mingtie, and Tash plutons. Hf isotopic compositions of chondrite and depleted mantle are from Blichert–Toft and Albarede (1997).

5.4. Sr–Nd isotopic compositions at least two components. Based on our modeling, melts derived from Precambrian metaigneous (80%) and metasedimentary (20%) rocks Two Tahman granite samples (BL3–2 and BL3–4) were selected for could produce the parental magma of the Tahman granites (Fig. 8a). Sr–Nd isotopic analysis. They exhibit 87Sr/86Sr ratios ranging from Moreover, they have relatively consistent Sr-Nd isotopic compositions 143 144 T 0.714390 to 0.717548 and Nd/ Nd ratios from 0.512162 to and negative correlations among Al2O3, CaO, MgO, FeO , TiO2 vs. SiO2 0.512164. Initial 87Sr/86Sr ratios vary from 0.705638 to 0.705683, and (Fig. 9), all of which suggests that fractional crystallization played a

εNd(t) values range from −7.1 to −6.9. The samples yield TDM2 (Nd) key role during the evolution of the magma after partial melting. The T model ages of 1565 and 1576 Ma, respectively (Table 4 in Appendix). negative correlations of MgO, FeO ,TiO2 vs. SiO2 suggest maﬁcmineral Three Tasha granodiorite samples (BL7–1, BL7–2, and BL7–3) were fractional crystallization, and the negative correlations of Na2O, CaO, 87 86 selected for Sr–Nd isotopic analysis. They exhibit Sr/ Sr ratios ranging Al2O3, and Sr vs. SiO2 suggest plagioclase fractionation. The depletion from 0.710899 to 0.712164 and 143Nd/144Nd ratios from 0.512150 to in Nb-Ta-Ti likely resulted from the separation of Ti-bearing phases, 0.512158 (see Table 4 in Appendix). Initial 87Sr/86Sr ratios vary from such as ilmenite and titanite. The Tahman granites have relatively 0.708450 to 0.708797, and εNd(t) values range from −7.1 to −7.3. high Yb (2.7 to 4.9 ppm, N1.9 ppm) and Y (25.5 to 46.5 ppm, N18

The samples yield TDM2 (Nd) model ages between 1578 and 1590 Ma ppm) contents (Fig. 9), and show flat HREE patterns, indicating garnet (Table 4 in Appendix). was not a residual phase. They also have relatively low Sr (115–197 ppm), and show negative Eu anomalies, which requires melting of a source rock within the stability field of plagioclase. Most samples plot T 6. Discussion within the metabasaltic amphibolite field in the (Na2O+K2O + FeO T +MgO+TiO2) vs. (Na2O+K2O)/(FeO +MgO+TiO2) magma source 6.1. Petrogenesis and magma source discrimination diagram (Fig. 5e), and all the samples plot in the lower

crustal ﬁeld in the εNd(t) vs. εHf(t) diagrams (Fig. 8b). All these geo- 6.1.1. Tahman pluton chemical characteristics suggest that the source of the Tahman granites

The Tahman granites (BL3 series) contain 70.6%–75.2% SiO2 and is the lower crust. In Table 3 of the Appendix, the calculated Zr satura- 3.3%–4.5% K2O contents, yielding 0.98 mean A/CNK values (0.92–1.01, tion thermometry estimates ranging from 787 °C to 815 °C (ave. = b1.1). They show decreasing P2O5 concentrations with increasing SiO2 798 °C; Watson and Harrison, 1983), indicating low temperature gran- content (Fig. 9f). The samples do not have typical peraluminous min- ites (Miller et al., 2003). erals such as muscovite and garnet. These features conﬁrm the rocks In summary, the Tahman high-K calc-alkaline granites were formed of the Tahman pluton belong to high-K calc-alkaline, metaluminous, I- primarily by partial melting of the Precambrian metamorphic basement type granitoids (Fig. 5c, d). (including both metasedimentary and metaigneous rocks) in the lower The Tahman samples show similar Mg# to melts derived from the crust. The parental magma likely experienced extensive fractional crys- crust (Fig. 5f), suggesting that they might be produced by partial melt- tallization after partial melting. ing of crustal rocks without signiﬁcant mantle-derived magmas mixing during the generation of these granites. This is further supported by the relatively uniform εHf(t) values. Sr–Nd isotopic compositions of the 6.1.2. Tash pluton Tahman granites are different from those of the Precambrian Samples from the Tash granitoids (BL7 series) contain 66.7%–72.3% metaigneous or metasedimentary rocks in the western Kunlun terrane SiO2, 3.4%–4.1% K2O, and 14.5%–15.6% Al2O3. Samples are characterized (Liu et al., 2015), indicating that the parental magma is composed of by high Sr (mostly N400 ppm) and low Yb contents (mostly b1.9), but 8 S. Wang et al. / Lithos 364–365 (2020) 105549

Fig. 5. Diagrams showing the geochemical compositions of the Tash and Tahman granitoids. (a) (K2O+Na2O) vs. SiO2 diagram (after Middlemost, 1994) showing the classiﬁcation of the Tash and Tahman granitoids; (b) K2Ovs.SiO2 diagram (after Peccerillo and Taylor, 1976) illustrating the calc-alkaline to high-K calc-alkaline nature of the Tash and Tahman samples; (c) A/CNK

(molar Al2O3/(CaO + Na2O+K2O)) vs. SiO2 diagram (after Maniar and Piccoli, 1989) indicating theI-andS-type nature of theTash and Tahman granites; (d) (Na2O + K2O) vs. (Zr + Nb + Ce

+Y)diagram(Whalen et al., 1987), identifying I–S type granites. and (e) (Na2O+K2O)/(FeOT +MgO+TiO2)vs.Na2O+K2O+FeOT +MgO+TiO2 (in wt%; after Patiño Douce, 1999) (f) SiO2 vs. Mg# [=Mg/(Mg + FeT)] diagram (Jiang et al., 2013 and references therein) diagrams indicating magma source characteristics for the Tash and Tahman plutons; S. Wang et al. / Lithos 364–365 (2020) 105549 9

Fig. 6. Chondrite-normalization REE patterns and primitive mantle-normalized trace element diagrams for the Tash and Tahman granitoids. Chondrite-normalizaiton data are from Boynton (1984). Primitive mantle-normalized data are from Sun and McDonough (1989).

they have relatively higher Y (rarely b18 ppm) and lower Sr/Y ratios (16 granites. They are weakly peraluminous with most A/CNK values less to 34, b40) than those of adakites. According to the (Na2O+K2O) vs. (Zr than 1.1. The Tash granitoids also lack typical peraluminous minerals +Nb+Ce+Y)diagram(Fig. 5d), the Tash granitoids are not A-type such as muscovite, cordierite, and garnet. This indicates that they

Fig. 7. Rb versus (Yb + Ta) and Hf–Rb–Ta tectonic discrimination diagrams (after Pearce, 1996; Harris et al., 1986). The Tash and Tahmam arc-like granites have similar ages and similar geochemical features to the Mazar arc-like granites relating to the Longmu Co –Shuanghu suture, are ~50 Ma younger than the Kayizi arc-like granites and 30-45 Ma younger than the Bulunkou and Yuqikapa syn-collision granite relating to the Jinshajiang suture. WPG: Within-plate granitoid; VAG: volcanic arc granitoid; Syn-COLG: syn-collision granitoid; ORG: ocean ridge granitoid; post-COLG: post-collision granitoid. Data from Jiang et al. (2013), Liu et al. (2010, 2015),andWang et al. (2016a) also shown. 10 S. Wang et al. / Lithos 364–365 (2020) 105549

87 86 Fig. 8. (a) Initial Sr/ Sr vs. εNd (T) diagrams. Also shown are two binary mixing curves between Precambrian metasedimentary and metaigneous rocks in the western Kunlun terrane;

(b) Whole-rock εNd vs. zircon εHf diagram. Also shown are the ﬁelds for MORB, OIB and global sediments (after Jiang et al., 2013). Data from Liu et al. (2015) also shown.

represent weakly peraluminous, high-K calc-alkaline, I-type granitoids plutons consist of high-K calc-alkaline granitoids. Arc granites usually (Fig. 5c, d). have relatively low Rb and Yb + Ta contents (Pearce, 1996). The High-K, calc-alkaline, I-type granitoids can be generated either by par- Tahman and Tash samples overlap between the volcanic arc granite tial melting of mafic to intermediate igneous sources, or by advanced as- and post-collisional fields in the Rb vs. (Yb + Ta) tectonic classification similation fractional crystallization of mantle-derived basaltic parental diagram (after Pearce, 1996; Fig. 8a). This indicates that the samples magmas (Li et al., 2007b; Roberts and Clemens, 1993). Typically, high- have common geochemical characteristics of the two different tectonic K, I-type granitoid magma cannot be produced by the latter model ac- settings. We can separate the granites into volcanic arc granite and post- cording to experimental studies (Roberts and Clemens, 1993). Samples collision granite in the Hf–Rb–Ta tectonic classification diagram (after from the Tash pluton show relatively higher Mg# than partial melts de- Harris et al., 1986; Fig. 8b). rived from the crust (Fig. 5f), suggesting the involvement of mantle- We consider the Tahman and Tash plutons to be indicative of derived melts. But the Sr-Nd-Hf isotopic compositions suggest a major volcanic-arc granite based on several geological reasons besides the late Paleoproterozoic infracrustal source, which indicates the Proterozoic geochemical characteristics mentioned above. Firstly, the eastern basement rock plays a key role in the petrogenesis of the studied I-type Indosinian granite belt of the Pamir (e.g. Jiang et al., 2002, 2013; granitoid. Thus, the latter process is not favored for the origin of the Schwab et al., 2004; Zhang et al., 2004, 2005, 2016, 2018a,b)isnotcon- Tash granitoids. Melts of intermediate to silicic compositions produced sidered to be related to divergent double subduction or rollback models by dehydration melting of tholeiitic amphibolites are usually low in K2O (Fig. 1b). Moreover, the geochronological analysis in this study reveals and high in Na2O/K2O N 1 (e.g. Rapp and Watson, 1995; Rushmer, much younger ages than the 220–218 Ma post-collision granites in 1991). Potassium-rich melts, with Na2O/K2O b 1atSi2O N 65%, could be the Indosinian granite belt (Zhang et al., 2018b). Furthermore, the obtained using medium-to-high K basaltic compositions as starting ma- Indosinian granites in this paper are located along the southern edge terials (Sisson et al., 2005). All Tash samples show Na2O/K2O b 1, which of the Central Pamir block, and their zircon U-Pb ages agree well with suggests that the Tash granitoid magmas were likely generated by the geochronological, paleontological and stratigraphic data along the infracrustal medium-to-high K basaltic compositions. Additionally, they southern edge of the Central Pamir block (e.g. Angiolini et al., 2013, all plot within the metabasaltic amphibolite field in the (Na2O+K2O+ 2015; Hong et al., 2017; Chapman et al., 2018), whose significance is T T FeO +MgO+TiO2) vs. (Na2O+K2O)/(FeO +MgO+TiO2)magma discussed in the next section. Therefore, the Tash and Tahman granites source discrimination diagram (Fig. 5e). And they have negative εNd are interpreted to be arc-like granites related to Paleo-Tethyan subduc- (t) and εHf(t) values, which fall in the lower crust field of εNd(t) vs. εHf tion. Specifically, the Tahman granites are inferred to have formed via (t) values diagram (Fig. 8b). The Tash granitoids are low temperature partial melting of a mixed source of Precambrian metaigneous and granitoids with calculated Zr saturation thermometry ranging from 760 metasedimentary rocks in the lower crust, and the Tash pluton was °C to 803 °C (ave. = 790 °C; Watson and Harrison, 1983, Miller et al., formed partly from infracrustal medium-to-high K basaltic composi- 2003). They are most likely derived from the in situ melting of a lower tions within the garnet stability field of the lowermost crust. crustal source. The enrichment of Sr and the moderately negative Eu anomalies indicate a plagioclase-free source. The relatively low Y and 6.3. Paleo-Tethyan suture zones in the Pamir and Tibetan Plateau Yb contents and steep HREE patterns (GdN/YbN =2.0–2.5) might require melting of a source rock within the stability field of garnet. Taken together, it is likely the Tash granitoids were derived from a lowermost Burtman and Molnar (1993) summarized the characteristics of the crust source that was within the garnet stability field. Rushan-Pshart suture on the identification of an ophiolitic mélange along the west segment of the suture that includes basalt, ultramafic rocks, limestone, radiolarite, and deep water deposits. Eastward, the 6.2. Tectonic environment ophiolitic mélange along the suture zone becomes difficult to observe. The continuous stratigraphic sequence from Carboniferous to Jurassic High-K calc-alkaline magmatism is frequently present at active con- in Central Pamir constrains the passive continent margin of the Central tinental margins (e.g. Condie, 1976). Both the Tahman and the Tash Pamir, indicating that the Rushan-Pshart oceanic lithosphere subducted S. Wang et al. / Lithos 364–365 (2020) 105549 11

Fig. 9. SiO2 vs. major element oxides (wt%), selected trace elements (ppm), and Sr-Nd isotopic compositions for the Tash and Tahman granitoids.

to the north beneath the Central Pamir from the Late Jurassic to Early plutons along the southern edge of the Central Pamir block as part of Cretaceous. Recent paleontological and sedimentological studies the Rushan-Pshart suture. Previous stratigraphic studies failed to locate around the Rushan-Pshart suture further constrained the closure time the trace of the Rushan-Pshart suture in the eastern Pamir, nor could of the Rushan-Pshart ocean to around Late Triassic to Early Jurassic they identify ophiolitic mélange relating to the suture zone. The 230 (Angiolini et al., 2013, 2015). Volcanic rocks are developed south of Ma gabbro dikes were found along the southern edge of the Central the Rushan-Pshart suture zone. Schwab et al. (2004) attributed the Pamir around the Sino-Tajikistan boundary (Hong et al., 2017), which Yanshanian granite belt to be part of the Rushan-Pshart suture, whereas suggests the Rushan-Pshart Paleo-Tethyan ocean was not closed at Chapman et al. (2018) concluded that the Yanshanian granite belt re- 230 Ma. The stratigraphic sequence from Carboniferous to Jurassic is sulted from the low-angle subduction of the Shyok oceanic slab. continuous in the western part of the Central Pamir block, but the strata Chapman et al. (2018) further attributed several 210–195 Ma granite are in fault contact in the eastern Pamir. This shows the strata in the 12 S. Wang et al. / Lithos 364–365 (2020) 105549

Fig. 10a. Geodynamic model of convergence among the central Pamir-North Qiangtang block and surrounding blocks during the closure of the Paleo-Tethys ocean (after Yang et al., 2014; Zhai et al., 2016; Wang et al., 2018, 2019). Fig. 10b Paleogeographic reconstructions of the Tethyan region in the Late Permian, showing relative positions of the Pamir and Tibetan blocks, as well as the distribution of land and sea (after Metcalfe, 2013). Abbreviations: TA = Tarim; SC=South China; NC = North China; I = Indochina; NQ = North Qiangtang; CP = Central Pamir; SP = South Pamir; S = Sibumasu; SG = Songpan-Ganzi; WB = West Burma; SQ = South Qiangtang; L = Lhasa; A = Afghan; IA = Iran; T = Turkey; Fig. 10c. Preliminary correlation of tectonic blocks among the Pamir plateau, the Tibetan Plateau and Southeastern Asia. Abbreviations are as follows: JS: Jinshajiang suture; LSS: Longmu Co-Shuanghu suture; BNS: Bangong-Nujiang suture; YS: Yalong–Indus suture; TS: Tanymas suture; KS: Kudi suture; RPS: Rushan-Pshart suture; ShS: Shyok suture; SMS: Song Ma suture; CMS: Changning- Menglian suture; ATF: Altyn Tagh fault; KKF: Karakorum fault; LF: Longmu Co fault; KF: east Kunlun fault; LM: Longmen thrust fault; XXF: Xianshuihe–Xiaojiang fault; DBF: Dien Bien Phu fault; ASRR: Ailaoshan–Red River fault.

eastern Pamir experienced more intensive deformation than that in the In this study, we identified 206–201 Ma Tahman, Mingtie, and Tash western Pamir. granitic plutons in the Tashkurgan area along the southern edge of the Previous studies suggested that the three magmatic belts in the Central Pamir block. Geochemical and isotopic data from the Tahman Pamir were generated by northward subduction and sequential ac- and Tash plutons indicate that these granites are I-type volcanic arc cretion of blocks onto the southern margin of Eurasia during the clo- granites. However they are 30–50 Myr younger than those arc-like or sure of the Proto-, Paleo-, and Meso-Tethyan oceans (Jiang et al., syn-collision granites related to the northward subduction of the 2002, 2013; Mattern and Schneider, 2000; Schwab et al., 2004; Jinshajiang–Tanymas Paleo-Tethyan ocean slab (e.g. Zhang et al., Xiao et al., 2002, 2005; Zhang et al., 2004, 2005, 2016, 2018). Re- 2005; Liu et al., 2010; Jiang et al., 2013; Wang et al., 2016a; Fig. 7). cently, the observation of I-type, arc-like granitic plutons to the Thus, we exclude the 206–201 Ma arc-like granites to be related to the north and south of the North Qiangtang block has led to a double subduction of the Tanymas-Jinshajiang oceanic slab. We further inter- subduction zone model of the Tianshuihai-North Qiangtang block, pret that these granites were related to the convergence between the as represented by the Jinshajiang Suture to the north and the South Pamir and Central Pamir blocks (Fig. 10a). A similar relationship Longmu Co–Shuanghu Suture to the south (Fig. 1; Yang et al., has been proposed for the Indosinian granitic plutons along the south- 2014; Liu et al., 2015; Zhai et al., 2011, 2013, 2016; Li et al., 2019; ern edge of the Central Pamir block in Tajikistan (Chapman et al., Wang et al., 2019). 2018). This interpretation is further supported by paleontological and S. Wang et al. / Lithos 364–365 (2020) 105549 13 stratigraphic studies that indicated that the Cimmerian block was ac- 7. Conclusions creted to Central Pamir along the Rushan-Pshart Suture between the Late Triassic and Early Jurassic (Angiolini et al., 2013, 2015). The conclu- We have conducted geochronological and geochemical studies on sion is also supported by the ~232 Ma gabbro dike intruded in early three plutons in Central Pamir, in order to understand their tectonic set- Paleozoic marine sediments along the southern edge of the Central tings and lateral correlations. Zircon U-Pb dating reveals the emplace- Pamir block (Hong et al., 2017). Thus, the Rushan-Pshart Suture is ment ages of ~206 Ma to ~201 Ma for the Tahman, Tash, and Mingtie best interpreted as a Paleo-Tethyan suture. Since the chronology and granitic plutons along the southern edge of the Central Pamir block. kinematics of the Rushan-Pshart ocean subduction are similar to that Geochemical and isotopic characteristics of the Tahman and Tash plu- of the Longmu Co – Shuanghu ocean subduction around Mazha (Liu tons show I-type, arc-like granitoids. Moreover, our analyses suggest et al., 2015), we therefore propose that the Rushan-Pshart suture is that the Tahman pluton was formed by partial melting and mixing be- the western extension of the Longmu Co-Shuanghu suture. Further- tween Precambrian metaigneous and metasedimentary rocks in the more, the Central Pamir block is bounded by the Rushan-Pshart lower crust. While the Tash pluton was derived from infracrustal Paleo-Tethyan suture to the south and by the Tanymas Paleo- medium-to-high K basaltic compositions within the garnet stability Tethyan suture to the north. The double Paleo-Tethyan suture struc- field of the lowermost crust. Therefore, we attribute that the I-type, ture of the Central Pamir block is also consistent with the arc-like granites are related to the subduction of the Rushan-Pshart Tianshuihai–North Qiangtang block in the Tibetan Plateau, which is Paleo-Tethyan oceanic slab. We have correlated the Tanymas Suture bounded by the Longmu Co-Shuanghu suture to the south and the to the Jinshajiang Suture and the Rushan-Pshart Suture to the Longmu Jinshajiang suture to the north. Co–Shuanghu Suture, which indicates that the Central Pamir block be- longs to the western extension of the Tianshuihai-North Qiangtang block. The main Paleo-Tethyan oceans (the Rushan-Pshart - Longmu 6.4. Oblique convergence of the Central Pamir-North Qiangtang-Indochina Co-Shuanghu - Changning-Menglian - Inthanon Paleo-Tethyan ocean) block with adjacent blocks and its branches (the Tanymas - Jinshajiang - Song Ma Paleo-Tethyan ocean) both exhibit diachronous closure from west to east, which may It appears that the Central Pamir, North Qiangtang, and Indochina suggest oblique plate convergence between the Central Pamir-North micro-blocks are all bounded by a double Paleo-Tethyan suture (the Qiangtang-Indochina block with the adjacent blocks along the southern Jinshajiang - Song Ma suture to the northern and eastern boundary, margin of Eurasia during the Late Triassic – Early Jurassic. and the Rushan-Pshart - Longmu Co-Shuanghu - Changning- Supplementary data to this article can be found online at https://doi. Menglian - Inthanon suture to the southern and western boundary) org/10.1016/j.lithos.2020.105549. (e.g. Li et al., 2019; Liu et al., 2015; Metcalfe, 2013; Wang et al., 2016b, 2019; Wu et al., 1995). This suggests that the micro-blocks belong to a single block similar to the east Cimmerian block (i.e. south Declaration of Competing Interest Pamir-south Qiangtang-Sibumasu block) (Fig. 10b, c). This inference is also supported by the 2.2–1.7 Ga gneiss age of the Bulunkuole We declare that we do not have any commercial or associative inter- Group in the Central Pamir and Tianshuihai micro-blocks (Ji et al., est that represents a conflict of interest in connection with the work 2011), that have similar ages as the Jitang and Ningduo groups in the submitted. Qamdo region in the Tibetan Plateau (He et al., 2011; Li et al., 2006, 2009) and as the 2.0–1.6 Ga basement ages from the Indochina Acknowledgments micro-block (Wang et al., 2016b). Furthermore, the warm-water Cathaysian fossil assemblages of the Upper Devonian–Lower Permian This study was financially supported by the National Key R&D Pro- sandstone and shale in the Tianshuiha Terrane are similar to those of gram of China (2018YFC1505001) and the China Geological Survey the North Qiangtang–Simao–Indochina block (Cui et al., 2006; Li (project DD20190717). We thank Wang Xinyu and Duan Lei for their as- et al., 2009; Metcalfe, 2013; Xia et al., 2006). Thus, it is possible that sistance during fieldwork. We also thank three anonymous reviewers the Central Pamir block is the western extension of the North and Dr. G. Shellnutt (Co-Editor-in-Chief) provided thoughtful and con- Qiangtang-Indochina block. structive reviews of the manuscript. The closure time of the Rushan-Pshart Paleo-Tethyan ocean in Pamir was no later than the Early Jurassic (Angiolini et al., 2013). In central References Tibet, the Longmu Co-Shuanghu ocean opened around 470 Ma and closed in the Middle Triassic (~220 Ma) based on geochronological Andersen, T., 2002. Correction of common lead in U-Pb analyses that do not report 204Pb. Chem. Geol. 192, 59–79. and geochemical characteristics of the Longmu Co-Shuanghu ophiolitic Angiolini, L., Zanchi, A., Zanchetta, S., Nicora, A., Vezzoli, G., 2013. The Cimmerian melange (Zhai et al., 2011, 2013, 2016). Southeastward, the Changning- geopuzzle: new data from South Pamir. Terra Nova 25, 352–360. Menglian ocean opened around 440 Ma and closed around 230 Ma, as Angiolini, L., Zanchi, A., Zanchetta, S., Nicora, A., Vuolo, I., Berra, F., Henderson, C., Malaspina, N., Rettori, R., Vachard, D., Vezzoli, G., 2015 Apr 15. From rift to drift in deduced from paleontology and from the Changning-Menglian south pamir (tajikistan): permian evolution of a cimmerian terrane. J. Asian Earth ophiolitic melange data (Jian et al., 2009b; Ueno, 2003; Wu et al., Sci. 102, 146–169. 1995), which is similar to the Inthanon suture in Thailand (Metcalft, Bi, H., Wang, Z., Wang, Y., Zhu, X., 1999. History of tectono-magmatic evolution in the Western Kunlun Orogen. Sci. China Ser. D-Earth Sci. 604–619. 2013). Thus, the closure time of the main Paleo-Tethyan ocean exhibits Bian, X., Zhu, H., Ji, W., Cui, J., Luo, Q., 2013. The discovery of Qingbaikou plutonite in an aging trend from west to east. On the contrary, the Tanymas Taxorgan, Xinjiang, and evidence from zircon LA-ICPMS dating of intrusive rock. (Jinshajiang) ocean in Central Pamir closed around 241 Ma based on Northwest. Geol. 46 (1), 22–31 (In Chinese with English Abstract). – syn-collisional granites (e.g. Jiang et al., 2002, 2013; Liu et al., 2010, Blichert-Toft, J., Albarede, F., 1997. The Lu Hf geochemistry of chondrites and the evolution of the mantle-crust system. Earth Planet. Sci. Lett. 148, 243–258. 2015; Zhang et al., 2005; Wang et al., 2016a). Eastwardly, the closure Boynton, W.V., 1984. Cosmochemistry of the Rare Earth Elements: Meteorite Studies. time of the Jinshajiang ocean in central and east Tibet is around Elsevier Science Publishing Company, Amsterdam, pp. 63–144. 220–210 Ma, as constrained by the Jinshajiang ophiolitic melange and Bureau of Geology and Mineral Resources of Xinjiang Uygur Autonomous Region (Xinjiang BGMR), 2006. Geology and Mineral Resources Map of Tashkulhan, Scale syn-collision granites (Jian et al., 2009a; Yang et al., 2014; Zi et al., 1:200000. Geological Publishing House, Beijing (in Chinese). 2012). The main Paleo-Tethyan oceans and its branches both exhibit Burtman, S., Molnar, P., 1993. Geological and geophysical evidence for deep subduction of – diachronous closure from west to east, this pattern is consistent with continental crust beneath the Pamir. Geol. Soc. Am. Spec. Pap. 281, 1 76. Chapman, J., Scoggin, S., Kapp, P., Carrapa, B., Ducea, M., Worthington, J., Oimahmadov, I., oblique plate convergence of the Central Pamir-North Qiangtang- Gadoev, M., 2018. Mesozoic to Cenozoic magmatic history of the Pamir. Earth Planet. Indochina block with adjacent blocks (Fig. 10b). Sci. Lett. 482, 181–192. 14 S. Wang et al. / Lithos 364–365 (2020) 105549

Chen, F.K., Li, X.H., Wang, X.L., Li, Q.L., Siebel, W., 2007. Zircon age and Nd–Hf isotopic Liu, Z., Jiang, Y., Jia, R., Zhao, P., Zhou, Q., 2015. Origin of Late Triassic high-K calc-alkaline composition of the Yunnan Tethyan belt, southwestern China. Int. J. Earth Sci. 96 granitoids and their potassic microgranular enclaves from the western Tibet Plateau, (6), 1179–1194. northwest China: Implications for Paleo-Tethys evolution. Gondwana Res. 27, Condie, K.C., 1976. Plate Tectonics and Crustal Evolution. second ed. Pergamon Press, New 326–341. York. Ludwig, K.R., 2003. Users Manual for Isoplot/Ex rev. 3.0, Spec. Publ. 1a. Berkeley Cui, J., Bian, X., Wang, J., Yang, K., Zhu, H., Zhang, J., 2006. Discovery of an unconformity Geochronol, Cent., Berkeley, Calif. between the Lower Silur ian and Middle Devonian in the Tianshuihu area, southern Maniar, P.D., Piccoli, P.M., 1989. Tectonic discrimination of granitoids. Geol. Soc. Am. Bull. Kangxiwar, West Kunlun, China. Geol. Bull. China 25 (12), 1437–1440 (In Chinese 101, 635–643. with English Abstract). Mattern, F., Schneider, W., 2000. Suturing of the Proto- and Paleo-Tethys oceans in the Griffin, W.L., Pearson, N.J., Belousova, E., Jackson, S.E., van Achterbergh, E., O'Reilly, S.Y., western Kunlun (Xijiang, China). J. Asian Earth Sci. 18, 637–650. Shee, S.R., 2000. The Hf isotope composition of cratonic mantle: LA–MC–ICP–MS Metcalfe, I., 2013. Gondwana dispersion and Asian accretion: tectonic and analysis of zircon megacrysts in kimberlites. Geochim. Cosmochim. Acta 64, 133–147. palaeogeographic evolution of the eastern Tethys. J. Asian Earth Sci. 66, 1–33. Harris, N.B.W., Pearce, J.A., Tindle, A.G., 1986. Geochemical characteristics of collision zone Middlemost, E.A.K., 1994. Naming materials in the magma/igneous rock system. Earth Sci. magmatism. In: Coward, M.P., Rles, A.C. (Eds.), Collision Tectonics. Geological Society, Rev. 37, 215–224. London, Special Publications vol. 19, pp. 67–81. Miller, C.F., Mcdowell, S.M., Mapes, R.W., 2003. Hot and cold granites? Implications of zir- He, S.P., Li, R.S., Wang, C., Zhang, H.F., Ji, W.H., Yu, P.S., Gu, P.Y., Shi, C., 2011. Discovery of con saturation temperatures and preservation of inheritance. Geology 31 (6), ~4.0 Ga detrital zircons in the Changdu Block, North Qiangtang, Tibetan Plateau. Chin. 529–532. Sci. Bull. 56, 573–582. Patiño Douce, A.E., 1999. What do experiments tell us about the relative contributions of Hong, J., Ji, W., Zhang, H., Yao, W., 2017. LA-ICP-MS zircon U-Pb dating, geochemis⁃try and crust and mantle to the origin of granitic magmas? In: Castro, A., Fernandez, C., tectonic implications of the Qieshijiebie gabbro on the northern margin of South Vigneresse, J.L. (Eds.), Understanding Granites: Intergrating New and Classical Tech- – Pamir. Geol. Bull. China 33 (6), 820–829 (In Chinese with English abstract). niques, 168. Special Publications, Geological Society London, pp. 55 75 – Hou, K.J., Li, Y.H., Zou, T.R., Qu, X.M., Shi, Y.R., Xie, G.Q., 2007. Laser ablation-MC-ICP-MS Pearce, J.A., 1996. Sources and settings of granitic rocks. Episodes 19, 120 125. technique for Hf isotope microanalysis of zircon and its geological applications. Peccerillo, A., Taylor, S.R., 1976. Geochemistry of Eocene calc-alkaline volcanic rocks from – Acta Petrol. Sin. 23, 2595–2604 (in Chinese with English abstract). the Kastamonu area, northern Turkey. Contrib. Mineral. Petrol. 58, 63 81. Huang, J., 2001. Tectonic characteristics and evolution of the Qiangtang basin. Reg. Geol. Qu, J., Zhang, L., Ai, Y., Lu, Z., Wang, J., 2007. High-pressure granulite from Western Kun- China 20 (3), 178–186 (In Chinese with English abstract). lun, northwestern China: Its metamorphic evolution, zircon SHRIMP U-Pb ages and – Ji, W., Li, R., Chen, S., He, S., Zhao, Z., Bian, X., 2010. The Proterozoic Volcanic Rock Discov- tectonic implication. Sci. China Ser. D-Earth Sci. 50, 961 971. – ery and Its Geological Significance in Tianshuihai Block. Science China Series D-Earth Rapp, R.P., Watson, E.B., 1995. Dehydration melting of metabasalt at 8 32 kbar: implica- – – Science, Xinjiang, West China https://doi.org/10.1007/s11430-010-4043-7. tions for continental growth and crust mantle recycling. J. Petrol. 36, 891 931. Ji, W.H., Li, R.S., Chen, S.J., He, S.P., Zhao, Z.M., Bian, X., 2011. The discovery of Roberts, M.P., Clemens, J.D., 1993. Origin of high-potassium, calc-alkaline, I-type granit- – Palaeoproterozoic volcanic rocks in the Bulunkuoler Group from the Tianshuihai oids. Geology 21, 825 828. Massif in Xinjiang of Northwest China and its geological significance. Science China Robinson, A., 2015. Mesozoic tectonics of the Gondwanan terranes of the Pamir plateau. – Earth Sciences 54 (1), 61–72. J. Asian Earth Sci. 102, 170 179. Rushmer, T., 1991. Partial melting of two amphibolites: contrasting experimental results Jian, P., Liu, D.Y., Kröner, A., Zhang, Q., Wang, Y.Z., Sun, X.M., Zhang, W., 2009a. Devonian under fluid-absent conditions. Contrib. Mineral. Petrol. 107, 41–59. to Permian plate tectonic cycle of the Paleo-Tethys Orogen in southwest China (I): geochemistry of ophiolites, arc/back-arc assemblages and within-plate igneous Schwab, M., Ratschbacher, L., Siebel, W., McWilliams, M., Minaev, V., Lutkov, V., Chen, F., rocks. Lithos 113, 748–766. Stanek, K., Nelson, B., Frisch, W., Wooden, J.L., 2004. Assembly of the Pamirs: Age and origin of magmatic belts from the southern Tien Shan to the southern Pamirs Jian, P., Liu, D.Y., Kröner, A., Zhang, Q., Wang, Y.Z., Sun, X.M., Zhang, W., 2009b. Devonian and their relation to Tibet. Tectonics 23, TC4002. to Permian plate tectonic cycle of the Paleo-Tethys Orogen in southwest China (II): Sengör, A.M.C., 1984. The Cimmeride orogenic system and the tectonics of Eurasia. Geol. insights from zircon ages of ophiolites, arc/back-arc assemblages and withinplate ig- Soc. Am. Spec. Pap. 195, 1–82. neous rocks and generation of the Emeishan CFB province. Lithos 113, 767–784. Sisson, T.W., Ratajeski, K., Hankins, W.B., Glazner, A.F., 2005. Voluminous granitic magmas Jiang, Y., Jiang, S., Ling, H., Zhou, X., Rui, X., Yang, W., 2002. Petrology and geochemistry of from common basaltic sources. Contrib. Mineral. Petrol. 148, 635–661. shoshonitic plutons from the western Kunlun orogenic belt, northwestern Xinjiang, Sobel, E., Schoenbohm, L., Chen, J., Thiede, R., Stockli, D.F., Sudo, M., Strecker, M.R., 2011. China: implications for granitoid geneses. Lithos 63, 165–187. Late Miocene–Pliocene deceleration of dextral slip between Pamir and Tarim: Impli- Jiang, Y., Liu, Z., Jia, R., Liao, S., Zhou, Q., Zhao, P., 2012. Miocene potassic granite-syenite cations for Pamir orogenesis. Earth Planet. Sci. Lett. 304, 369–378. association in western Tibetan Plateau: implications for shoshonitic and high Ba-Sr Strecker, M.R., Frisch, W., Hamburger, M.W., Ratschbacher, L., Semiletkin, S., Zamoruyev, granite genesis. Lithos 134-135, 146–162. A., Sturchio, N., 1995. Quaternary deformation in the eastern Pamirs, Tadzhikistan Jiang, Y., Jia, R., Liu, Z., Liao, S., Zhao, P., Zhou, Q., 2013. Origin of Middle Triassic high-K and Kyrgyzstan. Tectonics 14, 1061–1079. calc-alkaline granitoids and their potassic microgranular enclaves from the western Sun, S.S., McDonough, W.F., 1989. chemical and isotopic systematics of oceanic basalts: Kunlun orogen, northwest China: a record of the closure of Paleo-Tethys. Lithos implications for mantle composition and processes. In: Saunders, A.D., Norry, M.J. 156-159, 13–30. (Eds.), Magmatism in the Ocean Basins. Geological Society, London, Special Publica- Kang, L., Xiao, P., Gao, X., 2012. Geochemical characteristics and petrogenesis of tions vol. 42, pp. 313–345. Muztaeata intrusion in Western Kunlun oroegnic belt and their tectonic significance. Ueno, K., 2003. The Permian fusulinoidean faunas of the Sibumasu and Baoshan blocks: Geol. Bull. China 31 (12), 2001–2014 (in Chinese with English abstract). their implications for the paleogeographic and paleoclimatologic reconstruction of Kang, L., Xiao, P., Gao, X., Xi, R., Yang, Z., 2015. Neopaleozoic and Mesozoic granitoid the Cimmerian Continent. Palaeogeogr. Palaeoclimatol. Palaeoecol. 193, 1–24. magmatism and tectonic evolution of the western West Kunlun Mountains. Geol. Wang, C., Liu, L., Korhonen, F., Yang, W., Cao, Y., 2016a. Origins of Early Mesozoic granit- – China 42 (3), 533 552 (in Chinese with English abstract). oids and their enclaves from West Kunlun, NW China: implications for evolving Lacassin, R., Valli, F., Arnaud, N., Leloup, P.H., Paquette, J.L., Li, H., Tapponnier, P., Chevalier, magmatism related to closure of the Paleo-Tethys. Int. J. Earth Sci. 105 (3), 941–964. M.L., Guillot, S., Maheo, G., Xu, Z., 2004. Large-scale geometry, offset and kinematic Wang, S., Mo, Y., Wang, C., Ye, P., 2016b. Paleotethyan evolution of the Indochina block as – – evolution of the Karakoram fault, Tibet. Earth Planet. Sci. Lett. 219 (3 4), 255 269. deduced from granites in northern Laos. Gondwana Res. 38, 183–196. Li, C., Huang, X., Zhai, Q., 2006. The Longmu Co-Shuanghu-Jitang plate suture and the Wang, X., Wang, S., Wang, C., Chen, L., 2018. Late Permian to Late Triassic arc-like granit- northern boundary of Gondwanaland in the Qinghai-Tibet plateau. Earth Sci. Front. oids in the northern Lancangjiang tectonic belt, eastern Tibet: age, geochemistry, Sr- – 13 (4), 136 147 (In Chinese with English Abstract). Nd-Hf isotopes and tectonic implications. Lithos 308–309, 278–293. fi Li, B., Ji, W., Bian, X., Wang, F., Li, W., 2007a. The composition and geological signi cance of Wang, S., Yao, X., Jiang, W., 2019. Geochronological, geochemical, and Sr–Nd–Hf isotopic – the Mazha tectonic melange in west Kunlun mountains. Geoscience 21 (1), 78 86 (In characteristics of granitoids in eastern Tibet and implications for tectonic correlation Chinese with English Abstract). with southeastern Asia. Lithosphere 11 (3), 333–347. Li, X., Li, Z., Li, W., Liu, Y., Yuan, C., Wei, G., Qi, C., 2007b. U–Pb zircon, geochemical and Sr– Watson, E.B., Harrison, T.M., 1983. Zircon saturation revisited: temperature and composi- Nd–Hf isotopic constraints on age and origin of Jurassic Iand A-type granites from tion effects in a variety of crustal magma types. Earth Planet. Sci. Lett. 64, 295–304. central Guangdong, SE China: a major igneous event in response to foundering of a Whalen, J.B., Currle, K.L., Chappell, B.W., 1987. A-type granites: geochemical characteris- subducted flat-slab? Lithos 96, 186–204. tics, discrimination and petrogenesis. Contrib. Mineral. Petrol. 95, 407–419. Li, C., Zhai, Q.G., Dong, Y.S., Liu, S., Xie, C.M., Wu, Y.W., 2009. High-pressure Wu, H., Boulter, C.A., Ke, B., Stow, D.A.V., Wang, Z., 1995. The Changning-Menglian suture eclogiteblueschist metamorphic belt and closure of paleo-Tethys Ocean in Central zone; a segment of the major Cathaysian -Gondwana divide in Southeast Asia. Qiangtang, Qinghai-Tibet Plateau. J. Earth Sci. 20, 209–218. Tectonophysics 242, 267–280. Li, J., Niu, Y., Hu, Y., Chen, S., Zhang, Y., Duan, M., Sun, P., 2016. Origin of the late Early Cre- Xia, J., Zhong, H., Tong, J., Lu, R., 2006. Unconformity between the lower Ordovician and taceous granodiorite and associated dioritic dikes in the Hongqilafu pluton, north- Devonian in the Sanchakou area in the easter part of the Longmu Co, northern western Tibetan Plateau: a case for crustmantle interaction. Lithos 260, 300–314. Tibet, China. Geol. Bull. China 25 (1–2), 113–117 (In Chinese with English Abstract). Li, S., Chung, S.-L., Hou, Z., Chew, D., Wang, T., Wang, B., Wang, Y., 2019. Early Mesozoic Xiao, W., Windley, B.F., Chen, H., Zhang, G., Li, J., 2002. Carboniferous–Triassic subduction magmatism within the Tibetan Plateau: Implications for the Paleo-Tethyan tectonic and accretion in the western Kunlun, China: implications for the collisional and ac- evolution and continental amalgamation. Tectonics 38, 3505–3543. cretionary tectonics of the northern Tibetan plateau. Geology 30, 295–298. Liu, Y., Hu, Z.C., Gao, S., Günther, D., Xu, J., Gao, C.G., Chen, H.H., 2008. In situ analysis of Xiao, W., Windley, B.F., Liu, D., Jian, P., Liu, C., Yuan, C., Sun, M., 2005. Accretionary tecton- major and trace elements of anhydrous minerals by LA–ICP–MS without applying ics of the Western Kunlun orogen, China: a Paleozoic–Early Mesozoic, long-lived ac- an internal standard. Chem. Geol. 257, 34–43. tive continental margin with implications for the growth of southern Eurasia. J. Geol. Liu, J., Wang, H., Li, S., Tong, L., Ren, G., 2010. Geological and geochemical features and 113, 687–705. geochronology of the Kayizi Porphyry molybdenum deposit in the northern belt of Yang, W.Q., Liu, L., Cao, Y.T., Wang, C., He, S., 2010. Geochronological evidence of western Kunlun, NW China. Acta Petrol. Sin. 26 (10), 3095–3105. Indosinian (high-pressure) metamorphic event and its tectonic significance in S. Wang et al. / Lithos 364–365 (2020) 105549 15

Taxkorgan area of the Western Kunlun Mountains, NW China. Sci. China Earth Sci. 53, Zhang, C., Yu, H., Wang, A., Guo, K., 2005. Dating of Triassic granites in the Western Kun- 1445–1459. lun Mountains and its tectonic implications. Acta Geol. Sin. 79, 645–652 (in Chinese Yang, T., Ding, Y., Zhang, H., Fan, J., Liang, M., Wang, X., 2014. Two-phase subduction and with English abstract). subsequent collision deﬁnes the Paleotethyan tectonics of the southeastern Tibetan Zhang, Q., Liu, Y., Huang, H., Wu, Z.H., Zhou, Q., 2016. Petrogenesis and tectonic implica- plateau: evidence from zircon U-Pb dating, geochemistry, and structural geology of tions of the high-K Alamas calc-alkaline granitoids at the northwestern margin of the Sanjiang orogenic belt, Southwest China. Geol. Soc. Am. Bull. 126, 1652–1682. the Tibetan Plateau: geochemical and Sr–Nd–Hf–O isotope constraints. J. Asian – Yin, A., Harrison, T.M., 2000. Geologic evolution of the Himalayan-Tibetan Orogen. Annu. Earth Sci. 127, 137 151. Rev. Earth Planet. Sci. 28, 211–280. Zhang, Q., Liu, Y., Wu, Z., Huang, H., Li, K., Zhou, Q., 2018. Late Triassic granites from the Zhai, Q., Jahn, B.N., Zhang, Y., Wang, J., Li, S., 2011. Triassic subduction of the Paleo- Tethys northwestern margin of the Tibetan Plateau, the Dahongliutan example: petrogenesis in northern Tibet, China: evidence from the geochemical and isotopic characteristics and tectonic implications for the evolution of the Kangxiwa Palaeo-Tethys. Int. Geol. – of eclogite and blueschists of Qiangtang Block. J. Asian Earth Sci. 42, 1356–1370. Rev. 61 (2), 175 194. Zhang, C., Zou, H.B., Ye, X.T., Chen, X.Y., 2018a. Timing of subduction initiation in the Zhai, Q., Jahn, B., Su, L., Wang, J., Mo, X., Lee, H., Wang, K., Tang, S., 2013. Triassic arc Proto-Tethys Ocean: Evidence from the Cambrian gabbros from the NE Pamir Plateau. magmatism in the Qiangtang area, northern Tibet: Zircon U-Pb ages, geochemical Lithos 314, 40–51. and Sr-Nd-Hf isotopic characteristics, and tectonic implications. J. Asian Earth Sci. Zhang, C.L., Zou, H.B., Ye, X.T., Chen, X.Y., 2018b. Tectonic evolution of the NE section of 63, 162–178. the Pamir Plateau: new evidence from ﬁeld observations and zircon U-Pb geochro- Zhai, Q., Jahn, B., Wang, J., Hu, P., Chung, S., Lee, H., Tang, S., 2016. Oldest Paleo-Tethyan nology. Tectonophysics 723, 27–40. – ophiolitic mélange in the Tibetan Plateau. Geol. Soc. Am. Bull. 128 (3/4), 355 373. Zi, J., Cawood, P.A., Fan, W., Wang, Y., Tohver, E., McCuaig, T., Peng, T., 2012. Triassic colli- Zhang, C., Yu, H., Shen, J., Dong, Y., Ye, H., 2004. Zircon SHRIMP Age Determination of the sion in the Paleo-Tethys Ocean constrained by volcanic activity in SW China. Lithos Giant-crystal Gabbro and Basalt in Kudi, West Kunlun: Dismembering of the Kudi 144-145, 145–160. ophiolite. Geol. Rev. 50 (6), 639–643.