| Citation: |
Yuan Tang, Ya-dong Qin, Xiao-dong Gong, Yong Li, Dong-bing Wang, Bao-di Wang, 2023. Petrology, geochemistry and Ar-Ar geochronology of eclogites in Jinshajiang orogenic belt, Gonjo area, eastern Tibet and restriction on Paleo-Tethyan evolution, China Geology, 6, 285-302. doi: 10.31035/cg2023025
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Petrology, geochemistry and Ar-Ar geochronology of eclogites in Jinshajiang orogenic belt, Gonjo area, eastern Tibet and restriction on Paleo-Tethyan evolution
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Abstract
As one of the important Paleo-Tethys suture zones in eastern Tibet, the Jinshajiang orogenic belt is of great significance to study the tectonic evolution of the main suture zone of Paleo-Tethys. In this paper, eclogites developed in the Jinshajiang suture zone in Gonjo area, eastern Tibet, are selected as specific research objects, and petrological, geochemical and Ar-Ar geochronological analyses are carried out. The major element data of the whole rock reveals that the eclogite samples have the characteristics of picritic basalt-basalt and belong to the oceanic low potassium tholeiites. The results of rare earth elements and trace elements of the samples show that the protoliths of eclogites have characteristics similar to oceanic island basalt (OIB) or normal mid ocean ridge basalt (N-MORB). Muscovite (phengite) from two eclogite samples yield the Ar-Ar plateau ages of 247±2 Ma and 248±2 Ma respectively, representing the peak metamorphic age of eclogite facies and the timing of complete closure of the Jinshajiang Paleo-Tethys Ocean. Muscovite and biotite selected from the hosting rocks of eclogite yield the Ar-Ar plateau ages are 238±2 Ma and 225±2 Ma respectively, reflecting the exhumation age of eclogites and their hosting rocks. Combined with the zircon U-Pb dating data (244 Ma) of eclogites obtained in previous work, it can be concluded that the Jinshajiang Paleo-Tethys ocean was completely closed and arc-continent collision was initiated at about 248–244 Ma (T21). Subsequently, due to the large-scale arc (continent)-collision orogeney between Deqin-Weixi continental margin arc and Zhongza block (T31–T32), the eclogites were rapidly uplifted to the shallow crust.
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References
Bebout GE. 2007. Metamorphic chemical geodynamics of subduction zones. Earth and Planetary Science Letters, 260(3), 373–393. doi: 10.1016/j.jpgl.2007.05.050. Becker H, Jochum KP, Carlson RW. 2000. Trace elements fractionation during dehydration of eclogite from high-pressure terranes and the implications for element fluxes in subduction zones. Chemical Geology, 163, 65–69. doi: 10.1016/s0009-2541(99)00071-6. Carswell DA, Harley SI. 1990. Mineral barometry and thermometry. In:Carswell DA (ed.). Eclogite Facies Rocks. Blackie, Glasgow, 83–110. Chalot-Prat F, Ganne J, Lombard A. 2003. No significant element transfer from the oceanic plate to the mantle wedge during subduction and exhumation of the Tethys lithosphere (Western Alps). Lithos, 69, 69–103. doi: 10.1016/s0024-4937(03)00047-1. Chen W, Zhang Y, Zhang YQ, Jin GS, Wang QL. 2006. Late Cenozoic episodic uplifting in southeastern part of the Tibetan plateau-evidence from Ar-Ar thermochronology. Acta Petrologica Sinica, 22(4), 867–872 (in Chinese with English abstract). doi: 10.1016/j.sedgeo.2005.11.021. Dilek Y, Furnes H. 2011. Ophiolite genesis and global tectonics: geochemical and tectonic fingerprinting of ancient oceanic lithosphere. Geological Society of America Bulletin, 123, 387–411. doi: 10.1130/b30446.1. Dilek Y, Furnes H. 2014. Ophiolites and their origins. Elements, 10, 93–100. doi: 10.2113/gselements.10.2.93. Fan WM, Peng TP, Wang YJ. 2009. Triassic magmatism in the southern Lancangjiang zone, southwestern China and its constraints on the tectonic evolution of Paleo-Tethys. Earth Science Frontiers, 16(6), 291–302 (in Chinese with English abstract). doi: 10.3321/j.issn:1005-2321.2009.06.031. Gong XD, Tang Y, Qin YD, Wang BD, Wang DB, Liu H, Duan YY. 2020. Late Triassic collision of Jinshajiang suture belt: Geochronological, geochemical and Hf Isotope evidences from Quartz Monzonite in Gonjo area. Earth Science, 45(8), 2905–2919 (in Chinese with English abstract). doi: 10.3799/dqkx.2020.221. Guan C, Yan MD, Zhang WL, Zhang DW, Fu Q, Yu L, Xu WL, Zan JB, Li BS, Zhang T, Shen M. 2021. Paleomagnetic and chronologic data bearing on the Permian/Triassic boundary position of Qamdo in the eastern Qiantang terrane: Implications for the closure of the Paleo Tethys. Geophysical Research Letters, 48(6), 1–10. doi: 10.1029/2020GL092059. Hames WE, Bowring SA. 1994. An empirical evaluation of the argon diffusion geometry in muscovite. Earth and Planetary Science Letters, 124, 161–167. doi: 10.1016/0012-821x(94)00079-4. Harrison TM, Duncan I, Mcdougall I. 1985. Diffusion of 40Ar in biotite: temperature, pressure and compositional effects. Geochimica et Cosmochimica Acta, 49, 2461–2468. doi: 10.1016/0016-7037(85)90246-7. Huang K, Opdyke ND. 2016. Paleomagnetism of the Upper Triassic rocks from south of the Ailaoshan Suture and the timing of the amalgamation between the South China and the Indochina Blocks. Journal of Asian Earth Sciences, 119, 118–127. doi: 10.1016/j.jseaes.2015.12.005. Jian P, Liu D, Kroner A, Zhang Q, Wang YZ, Sun XM, Zhang W. 2009. Devonian to Permian plate tectonic cycle of the Paleo-Tethys Orogen in southwest China (II): insights from zircon ages of ophiolites, arc/back-arc assemblages and within-plate igneous rocks and generation of the Emeishan CFB province. Lithos, 113, 767–784. doi: 10.1016/j.lithos.2009.04.006. Jian P, Liu DY, Sun XM. 2008. SHRIMP dating of the Permo-Carboniferous Jinshajiang ophiolite, southwestern China: Geochronological constraints for the evolution of Paleo-Tethys. Journal of Asian Earth Sciences, 32, 371–384. doi: 10.1016/j.jseaes.2007.11.006. Le Bas MJ, Le Maitre RW, Streckeisen A, Zanenin B. 1986. A chemical classification of volcanic rocks based on the total alkali - silica diagram. Journal of Petrology, 27(3), 745–750. doi: 10.1093/petrology/27.3.745. Li XZ, Liu WJ, Wang YZ, Zhu QW. 1999. The tectonic evolution and metallogenesis in the tehys of the Nujiang-Langcangjiang-Jinshajiang area, southwestern china. Beijing: Geological Publishing House, 45–73, 122–132 (in Chinese with English abstract). Liu YS, Zong KQ, Kelemen PB, Gao S. 2008. Geochemistry and magmatic history of eclogites and ultramafic rocks from the Chinese continental scientific drill hole: subduction and ultrahigh-pressure metamorphism of lower crustal cumulates. Chemical Geology, 247, 133–153. doi: 10.1016/j.chemgeo.2007.10.016. Liu ZQ, Li XZ, Ye QT, Luo JN, Shen GF, Yang YQ. 1993. Division of Tectono-Magmatic zones and the distribution of deposits in the Sanjiang area. Beijing: Geological Publishing House, 6–89 (in Chinese with English abstract). McDonough WF, Sun SS. 1995. The composition of the Earth. Chemical Geology, 120(3–4), 223–253. doi: 10.1016/0009-2541(94)00140-4. Meschede M. 1986. A method of discriminating between different types of mid-ocean ridge basalts and continental tholeiites with the Nb–Zr–Y diagram. Chemical Geology, 56, 207–218. doi: 10.1016/0009-2541(86)90004-5. Metcalfe I. 2006. Palaeozoic and Mesozoic tectonic evolution and palaeogeography of East Asian crustal fragments: the Korean Peninsula in context. Gondwana Research, 9, 24–46. doi: 10.1016/j.gr.2005.04.002. Miyashiro A. 1974. Volcanic rock series in island arc and active continental margins. American Journal of Science, 274(4), 321–355. doi: 10.2475/ajs.274.4.321. Pan GT, Xu Q, Hou ZQ, Wang LQ, Du DX, Mo XX, Li DM, Wang MJ, Li XZ, Jiang XS. 2003. Archipelagic orogenesis, metallogenic systems and assessment of the mineral resources along the Nujiang-Langcangjiang-Jinshajiang area in southwestern China. Beijing: Geological Publishing House, 11–79 (in Chinese with English abstract). Pearce JA. 1982. Trace elements characteristic of lavas from destructive plate boundaries. Andesites[C]//Thorpe R S. Orogenic andesites and related rocks. Chichester, England: John Wiley & Sons, 525–548. Pearce JA. 2008. Geochemical fifingerprinting of oceanic basalts with applications to ophiolite classifification and the search for Archean oceanic crust. Lithos, 100, 14–48. doi: 10.1016/j.lithos.2007.06.016. Song PP, Ding L, Li ZY, Lippert PC, Yang TS, Zhao XX, Fu JJ, Yue YH. 2015. Late Triassic paleolatitude of the Qiangtang block: Implications for the closure of the Paleo-Tethys Ocean. Earth and Planetary Science Letters, 424, 69–83. doi: 10.1016/j.jpgl.2015.05.020. Spandler C, Hermann J, Arculus R, Mavrogenes J. 2004. Geochemical heterogeneity and element mobility in deeply subducted oceanic crust: insights from high-pressure mafic rocks from New Caledonia. Chemical Geology, 206, 21–42. doi: 10.1016/j.chemgeo.2004.01.006. Steiger RH, Jager E. 1977. Subcommission on geochronology: convention on the use of decay constants in geo- and cosmochronology. Earth and Planetary Science Letters, 36, 359–362. doi: 10.1016/0012-821X(77)90060-7. Sun SS, McDonough WF. 1989. Chemical and isotopic systematics of oceanic basalts: Implications for mantle composition and processes. geological society, London, Special Publication, 42, 313–345. doi: 10.1144/GSL.SP.1989.042.01.19. Sun XM, Jian P. 2004. The Wilson cycle of the Jinshajiang paleo-Tethys Ocean, in western Yunnan and western Sichuan Province. Geological Review, 50, 343–350 (in Chinese with English abstract). doi: 10.16509/j.georeview.2004.04.002. Tang Y, Liu YP, Wang P, Tang WQ, Qin YD, Gong XD, Wang DB, Wang BD. 2021. A new understanding of Demala Group complex in Chayu Area, southeastern Qinghai-Tibet Plateau: evidence from zircon U-Pb and mica 40Ar/39Ar dating. China Geology, 4, 77–94. doi: 10.31035/cg2021021. Tang Y, Qin YD, Gong XD, Duan YY, Chen G, Yao HY, Liao JX, Liao SY, Wang DB, Wang BD. 2020a. Discovery of eclogites in Jinsha River suture zone, Gonjo County, eastern Tibet and its restriction on Paleo-Tethyan evolution. China Geology, 1, 83–103. doi: 10.31035/cg2020003. Tang Y, Qin YD, Gong XD, Liu H, Wang DB, Wang BD. 2022a. Determination of material composition of Jinshajiang tectonic melange belt in Gonjo -Baiyu area, eastern Tibet. Sedimentary Geology and Tethyan Geology, 42(2), 260–278 (in Chinese with English abstract). doi: 10.19826/j.cnki.1009-3850.2022.04015. Tang Y, Wang DB, Liao SY, Wang BD, Yin FG. 2020b. Fabrics and 40Ar/39Ar ages of metamorphic rocks in the Gaoligong tectonic belt: implications for Cenozoic metamorphism and deformation in the SE Tibetan Plateau. Journal of Asian Earth Sciences, 192. doi: 10.1016/j.jseaes.2020.104270. Tang Y, Wang P, Deng H, Liu YP, Tang WQ. 2022b. Petrological records of major tectono-magmatic events since Oligocene in the southeastern segment of Xianshuihe fault zone in the eastern margin of Tibetan Plateau. Geological Bulletin of China, 41(7), 1121–1143 (in Chinese with English abstract). doi: 10.12097/j.issn.1671-2552.2022.07.001. Wang BD, Wang LQ, Wang DB, Li FQ, Tang Y, Wang QY, Yan GC, Wu Z. 2021. The temporal and spatial framework and its tectonic evolution of the Jinsha River arc-basin system, Southwest China. Sedimentary Geology and Tethyan Geology, 41(2), 246–264 (in Chinese with English abstract). doi: 10.19826/j.cnki.1009-3850.2021.02008. Wang BD, Wang LQ, Wang DB, Yin FG, He J, Peng ZM, Yan GC. 2018. Tectonic evolution of the Changning-Menglian Proto-Paleo Tethys Ocean in the Sanjiang Area, Southwestern China. Earth Science, 43(08), 2527–2550 (in Chinese with English abstract). doi: 10.3799/dqkx.2018.160. Wang BD, Wang LQ, Chen JL, Yin FG, Wang DB, Zhang WP, Chen LK, Liu H. 2014. Triassic three-stage collision in the Paleo-Tethys: Constraints from magmatism in the Jiangda-Deqen-Weixi continental margin arc, SW China. Gondwana Research, 26(2), 475–491. doi: 10.1016/j.gr.2013.07.023. Wang HN, Liu FL, Li J, Sun ZB, Ji L, Tian Z, Liu L, Santosh M. 2018. Petrology, geochemistry and P-T-t path of lawsonite-bearing retrograded eclogites in the Changning-Menglian orogenic belt, southeast Tibetan Plateau. Journal of Metamorphic Geology, 37(4), 439–478. doi: 10.1111/jmg.12462. Wang LQ, Pan GT, Li DM, Xu Q, Lin SL. 1999. The spatio-temporal framework and geological evolution of the Jinshajiang Arc-Basin systems. Act Geological Sinica, 73, 206–218 (in Chinese with English abstract). doi: 10.19762/j.cnki.dizhixuebao.1999.03.002. Wang XF, Metcalfe I, Jian P, He LQ, Wang CS. 2000. The Jinshajiang-Ailaoshan suture zone, China tectonostratigraphy, age and evolution. Journal of Asian Earth Sciences, 18, 675–690. doi: 10.1016/S1367-9120(00)00039-0. Wood DA. 1980. The application of a Th-Hf-Ta diagram to problems of tectonomagmatic classification and to establishing the nature of crystal contamination of basaltic lavas of the British Tertiaty Volcanic Province. Earth and Planetary Science Letters, 50(1), 11–30. doi: 10.1016/0012-821x(80)90116-8. Wu FY, Wan B, Zhao L, Xiao WJ, Zhu RX. 2020. Tethyan geodynamics. Acta Petrologica Sinica, 36(6), 1627–1674 (in Chinese with English abstract). doi: 10.18654/1000-0569/2020.06.01. Wu Z, Ji JP, Wang BD, Tang Y, Qin YD, Gong XD, He J. 2021. Zircon U-Pb age, geochemical characteristics and constraints on the Jinshajiang Paleo-Tethys collision of Early-Middle Triassic Malasongduo Formation volcanic rocks from the Gongjue area, Eastern Tibet. Geological Bulletin of China, 40(11), 1877–1891 (in Chinese with English abstract). doi: 10.12097/j.issn.1671-2552.2021.11.007. Xu ZQ, Dilek Y, Cao H, Yang JS, Robinson P, Ma CQ, Li HQ, Jolivet M, Roger F, Chen XJ. 2015. Paleo-Tethyan evolution of Tibet as recorded in the East Cimmerides and West Cathaysides. Journal of Asian Earth Sciences, 105, 320–337. doi: 10.1016/j.jseaes.2015.01.021. Yan YG, Zhao Q, Zhang YP, Huang BC, Zheng WJ, Zhang PZ. 2019. Direct Paleomagnetic constraint on the closure of Paleo‐Tethys and its implications for linking the Tibetan and southeast Asian Blocks. Geophysical Research Letters, 46, 14368–14376. doi: 10.1029/2019GL085473. Yang JS, Xu ZQ, Geng QR, Li ZL, Xu XZ, Li TF, Ren YF, Li HQ, Cai ZH, Liang FH, Chen SN. 2006. A possible new HP/UHP? metamorphic belt in China: Discovery of eclogite in the Lhasa terrane, Tibet Act Geological Sinica, 8(12), 1787–1792 (in Chinese with English abstract). doi: 10.1111/j.1745-4557.2006.00081.x. Yang JS, Xu ZQ, Li TF, Li HQ, Li ZL, Ren YF, Xu XZ, Chen SY. 2007. Oceanic subduction-type eclogite in the Lhasa block, Tibet, China: Remains of the Paleo-Tethys ocean basin? Geological Bulletin of China, 26(10), 1277–1287. doi: 10.1016/S1872-5791(07)60044-X. Yin FG, Xu B, Wang DB, Wang BD, Tang Y. 2021. Early Paleozoic magmatic event in the Sanjiang orogenic belt in southwest China and its response to the evolution of the Proto-Tethyan Ocean. Geological Bulletin of China, 40(6), 817–826 (in Chinese with English abstract). doi: 10.12097/j.issn.1671-2552.2021.06.001. Yu YS, Zhang H, Wang FM, Wang XM, Liu BZ, Qin FY, He H. 2019. Age and geochemical characteristics of Malasongduo Formation rhyolite in Riza Mountain, east Tibet, and its geological significance. Geological Bulletin of China, 38(05), 697–710 (in Chinese with English abstract). doi: 10.12097/j.issn.1671-2552.2019.05.001. Zhai QG, Zhang RY, Jahn BM, Li, C, Song SG, Wang J. 2011. Triassic eclogites from central Qiangtang, northern Tibet, China: petrology, geochronology and metamorphic P-T path. Lithos, 125, 173–189. doi: 10.1016/j.lithos.2011.02.004. Zhang RY, Lo CH, Chung SL, Grove M, Omori S, Iizuka Y, Liou JG, Tran VT. 2013. Origin and tectonic implication of ophiolite and eclogite in the Song Ma Suture Zone between the South China and Indochina Blocks. Journal of Metamorphic Geology, 31, 49–62. doi: 10.1111/jmg.12012. Zhang Y, Chen W, Chen KL, Liu XY. 2006. Study on the Ar-Ar age spectrum of diagenetic I/S and the mechanism of 39Ar recoil loss-Examples from the clay minerals of P-T boundary in Changxing, Zhejiang Province. Geological Review, 52(4), 556–561 (in Chinese with English abstract). doi: 10.3321/j.issn:0371-5736.2006.04.015. Zhong DL. 1998. The Paleotethys orogenic belt in west of Sichuan and Yunnan. Science Publishing House, Beijing, 1–230 (in Chinese with English abstract). Zhu JJ, Hu RZ, Bi XW, Zhong H, Chen H. 2011. Zircon U-Pb ages, Hf-O isotopes and whole-rock Sr-Nd-Pb isotopic geochemistry of granitoids in the Jinshajiang suture zone, SW China: constraints on petrogenesis and tectonic evolution of the Paleo-Tethys Ocean. Lithos, 126, 248–264. doi: 10.1016/j.lithos.2011.07.003. Zi JW, Cawood PA, Fan WM, Tohver E, Wang YJ, McCuaig TC, Peng TP. 2013. Late Permian-Triassic magmatic evolution in the Jinshajiang orogenic belt, SW China and implications for orogenic processes following closure of the Paleo-Tethys. American Journal of Science, 313, 81–112. doi: 10.2475/02.2013.02. Zi JW, Cawood PA, Fan WM, Wang YJ, Tohver E, McCuaig TC, Peng TP. 2012a. Triassic collision in the Paleo-Tethys Ocean constrained by volcanic activity in SW China. Lithos, 144–145, 145–160. doi: 10.1016/j.lithos.2012.04.020. Zi JW, Cawood PA, Fan WM, Wang YJ, Tohver E. 2012b. Contrasting rift and subduction-related plagiogranites in the Jinshajiang ophiolitic mélange, southwest China and implications for the Paleo-Tethys. Tectonics, 31, 1–18. doi: 10.1029/2011TC002937. -
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Yuan Tang, Ya-dong Qin, Xiao-dong Gong, Yong Li, Dong-bing Wang, Bao-di Wang, 2023. Petrology, geochemistry and Ar-Ar geochronology of eclogites in Jinshajiang orogenic belt, Gonjo area, eastern Tibet and restriction on Paleo-Tethyan evolution, China Geology, 6, 285-302. doi: 10.31035/cg2023025
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Figure 1.
a–Geotectonic position of the Jinshajiang orogenic belt (after Li XZ et al., 1999); b–geological sketch of Jinshajiang orogenic belt in eastern Tibet (location of the area shown in Fig. 1a).
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Figure 2.
Distribution characteristics of tectonic blocks in Jinshajiang suture zone, Gonjo County, Eastern Tibet (location shown in Fig. 1b).
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Figure 3.
a–Geological profile of eclogite and hosting rocks in Gonjo area; b and c–eclogites occurring in the shape of lens about 1–3 m wide, preserved in garnet-bearing plagioclase two-mica schist and banded marble; d–hand specimens of eclogite with low retrograde metamorphism. The bule stars show the location of samples.
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Figure 4.
Photomicrograph of eclogite (a, b, c, e, f) and hosting rock (d). Omp−omphacite; Grt−garnet; Qz−quartz; Phg−phengite; Cpx−clinopyroxene; Ab–albite; Act–actinolite; Pl−plagioclase; Bt−biotite; Ms−muscovite; Spn−Sphene; Ru−rutile; a, c, d and e −cross-polarized light; b and f−plane-polarized light.
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Figure 5.
a–SiO2 vs. (K2O+Na2O) diagram (modified from Le Bas MJ et al., 1986); b–SiO2 vs. (FeOt/MgO) diagram (modified from Miyashiro A, 1974) of eclogite samples from the Jinshajiang orogenic belt. Pc–Picritic basalt; B–Basalt; O1–Basaltic andesite; O2–Andesite; O3–Dacite; R–Rhyolite; S1–Trachybasalt; S2–Basaltic trachyandesite; S3–Trachyandesite; T–Trachyte, trachydacite; F–Foidite; U1–Tephritebasanite; U2–Phonotephrite; U3–Tephriphonolite; Ph–Phonolite.
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Figure 6.
a, c−The chondrite-normalized REE pattern diagram of samples; b, d−the primitive mantle-normalized trace-element spider diagram of samples (values of chondrites and primitive mantle from McDonough W and Sun SS, 1995).
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Figure 7.
40Ar/39Ar plateau age and 40Ar/36Ar-39Ar/36Ar isochron age of biotite and muscovite from samples. WMA–weighted mean age; MSWD–mean square of weighted deviates.
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Figure 8.
Discrimination diagrams for the eclogites. a−Zr vs. TiO2 (Pearce JA, 1982); b−Nb/Yb vs. Th/Yb (Pearce JA, 2008); c−Hf/3-Th-Ta (Wood DA, 1980); d−2Nb-Zr⁄4-Y (Meschede M, 1986).
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Figure 9.
Schematic diagram of tectonic evolution of Jinshajiang Paleo-Tethys orogenic belt (modified from Wang LQ et al., 1999)