Elemental and Sr–Nd isotopic geochemistry of the basalts and microgabbros in the Shuanggou ophiolite, SW China: implication for the evolution of the Palaeotethys Ocean | Geological Magazine | Cambridge Core (original) (raw)

Abstract

The Early Palaeozoic Shuanggou ophiolite is the best-preserved part of the Ailaoshan ophiolite belt. The microgabbros (basaltic dykes) and basalts (basaltic lavas) show distinct characteristics in geochemistry, implying that their genetic mechanisms are different. With Al2O3 contents ranging from 14.7% to 17.0%, the microgabbros belong to low-alumina type. They exhibit normal mid-ocean-ridge basalt (N-MORB) -like trace elemental characteristics with positive εNd(t) values (9.7–11.6) and slightly variable (87Sr/86Sr)i ratios (0.7036–0.7046). In contrast, the basalts have high Al2O3 contents (19.5–23.2%), therefore belonging to high-alumina type. A plagioclase-accumulation model is used to account for the high alumina contents. Moreover, the basalts have enriched MORB (E-MORB) -like trace element characteristics with lower εNd(t) values (6.4–8.0) and (87Sr/86Sr)i ratios (0.7032–0.7036). Their incompatible element ratios exhibit linear correlation with the isotopic data, which is probably related to the contribution of a mixed lithosphere–asthenosphere source. In summary, a two-stage model is proposed to explain the formation of the Shuanggou ophiolite: (1) at the continent–ocean transition stage, the basalts were generated by low-degree partial melting of the mixed mantle near a slow-spreading embryonic centre; and (2) at the mature stage of the Ailaoshan Ocean, the microgabbros were produced by moderate-degree partial melting of the depleted asthenospheric mantle.

References

Baker, D. R. & Eggler, D. H. 1983. Fractionation paths of atka (Aleutians) high-alumina basalts - constraints from phase-relations. Journal of Volcanology and Geothermal Research 18 (1–4), 387–404.CrossRefGoogle Scholar

Bartels, K. S., Kinzler, R. J. & Grove, T. L. 1991. High-pressure phase-relations of primitive high-alumina basalts from medicine lake Volcano, Northern California. Contributions to Mineralogy and Petrology 108 (3), 253–70.CrossRefGoogle Scholar

Brophy, J. G. 1989. Basalt convection and plagioclase retention - a model for the generation of high-alumina arc basalt. Journal of Geology 97 (3), 319–29.CrossRefGoogle Scholar

Brophy, J. G. & Marsh, B. D. 1986. On the origin of high-alumina arc basalt and the mechanics of melt extraction. Journal of Petrology 27 (4), 763–89.CrossRefGoogle Scholar

Crawford, A. J., Falloon, T. J. & Eggins, S. 1987. The origin of island-arc high-alumina basalts. Contributions to Mineralogy and Petrology 97 (3), 417–30.CrossRefGoogle Scholar

Deng, J., Wang, Q., Li, G., Li, C. & Wang, C. 2013. Tethys tectonic evolution and its bearing on the distribution of important mineral deposits in the Sanjiang region, SW China. Gondwana Research, published online 3 August 2013. doi: 10.1016/j.gr.2013.08.002.Google Scholar

Draper, D. S. & Johnston, A. D. 1992. Anhydrous P-T phase-relations of an Aleutian high-MgO basalt - an investigation of the role of olivine-liquid reaction in the generation of arc high-alumina basalts. Contributions to Mineralogy and Petrology 112 (4), 501–19.CrossRefGoogle Scholar

Eason, D. & Sinton, J. 2006. Origin of high-Al N-MORB by fractional crystallization in the upper mantle beneath the Galapagos Spreading Center. Earth and Planetary Science Letters 252 (3–4), 423–36.CrossRefGoogle Scholar

Falloon, T. J. & Green, D. H. 1987. Anhydrous partial melting of morb pyrolite and other peridotite compositions at 10 kbar - implications for the origin of primitive morb glasses. Mineralogy and Petrology 37 (3–4), 181–219.CrossRefGoogle Scholar

Fan, W. M., Wang, Y. J., Zhang, A. M., Zhang, F. F. & Zhang, Y. Z. 2010. Permian arc-back-arc basin development along the Ailaoshan tectonic zone: geochemical, isotopic and geochronological evidence from the Mojiang volcanic rocks, Southwest China. Lithos 119 (3–4), 553–68.CrossRefGoogle Scholar

Froitzheim, N. & Manatschal, G. 1996. Kinematics of Jurassic rifting, mantle exhumation, and passive-margin formation in the Austroalpine and Penninic nappes (eastern Switzerland). Geological Society of America Bulletin 108 (9), 1120–33.2.3.CO;2>CrossRefGoogle Scholar

Fujii, T. & Scarfe, C. M. 1985. Composition of liquids coexisting with spinel lherzolite at 10-kbar and the genesis of morbs. Contributions to Mineralogy and Petrology 90 (1), 18–28.CrossRefGoogle Scholar

Gust, D. A. & Perfit, M. R. 1987. Phase-relations of a high-Mg basalt from the Aleutian island-arc - implications for primary island-arc basalts and high-Al basalts. Contributions to Mineralogy and Petrology 97 (1), 7–18.CrossRefGoogle Scholar

Hopper, J. R., Funck, T., Tucholke, B. E., Larsen, H. C., Holbrook, W. S., Louden, K. E., Shillington, D. & Lau, H. 2004. Continental breakup and the onset of ultraslow seafloor spreading off Flemish Cap on the Newfoundland rifted margin. Geology 32 (1), 93–6.CrossRefGoogle Scholar

Jian, P., Liu, D. Y., Kroner, A., Zhang, Q., Wang, Y. Z., Sun, X. M. & Zhang, W. 2009 a. Devonian 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 rocks. Lithos 113 (3–4), 748–66.CrossRefGoogle Scholar

Jian, P., Liu, D. Y., Kroner, A., Zhang, Q., Wang, Y. Z., Sun, X. M. & Zhang, W. 2009 b. 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 (3–4), 767–84.CrossRefGoogle Scholar

Johnston, A. D. 1986. Anhydrous P-T phase-relations of near-primary high-alumina basalt from the South Sandwich Islands - implications for the origin of island arcs and Tonalite-Trondhjemite series rocks. Contributions to Mineralogy and Petrology 92 (3), 368–82.CrossRefGoogle Scholar

Kinzler, R. J. 1997. Melting of mantle peridotite at pressures approaching the spinel to garnet transition: application to mid-ocean ridge basalt petrogenesis. Journal of Geophysical Research 102 (B1), 853–74.CrossRefGoogle Scholar

Klemme, S., Günther, D., Hametner, K., Prowatke, S. & Zack, T. 2006. The partitioning of trace elements between ilmenite, ulvospinel, armalcolite and silicate melts with implications for the early differentiation of the moon. Chemical Geology 234 (3), 251–63.CrossRefGoogle Scholar

Lai, C.-K., Meffre, S., Crawford, A. J., Zaw, K., Halpin, J. A., Xue, C.-D. & Salam, A. 2013 a. The Central Ailaoshan Ophiolite and modern analogues. Gondwana Research 26 (1), 75–88.CrossRefGoogle Scholar

Lai, C.-K., Meffre, S., Crawford, A. J., Zaw, K., Xue, C.-D. & Halpin, J. A. 2013 b. The Western Ailaoshan Volcanic Belts and their SE Asia connection: A new tectonic model for the Eastern Indochina Block. Gondwana Research 26 (1), 52–74.CrossRefGoogle Scholar

Leloup, P. H., Lacassin, R., Tapponnier, P., Schärer, U., Zhong, D., Liu, X., Zhang, L., Ji, S. & Trinh, P. T. 1995. The Ailao Shan-Red River shear zone (Yunnan, China), Tertiary transform boundary of Indochina. Tectonophysics 251 (1), 3–84.CrossRefGoogle Scholar

McDonough, W. F. 1990. Constraints on the composition of the continental lithospheric mantle. Earth and Planetary Science Letters 101 (1), 1–18.CrossRefGoogle Scholar

Mckenzie, D. & O’Nions, R. 1991. Partial melt distributions from inversion of rare earth element concentrations. Journal of Petrology 32 (5), 1021–91.CrossRefGoogle Scholar

Mckenzie, D. & O’Nions, R. K. 1995. The source regions of ocean island basalts. Journal of Petrology 36 (1), 133–59.CrossRefGoogle Scholar

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 (3), 207–18.CrossRefGoogle Scholar

Metcalfe, I. 1996. Gondwanaland dispersion, Asian accretion and evolution of eastern Tethys. Australian Journal of Earth Sciences 43 (6), 605–23.CrossRefGoogle Scholar

Metcalfe, I. 2006. Palaeozoic and Mesozoic tectonic evolution and palaeogeography of East Asian crustal fragments: the Korean Peninsula in context. Gondwana Research 9 (1–2), 24–46.CrossRefGoogle Scholar

Metcalfe, I. 2011. Palaeozoic–Mesozoic history of SE Asia. In The SE Asian Gateway: History and Tectonics of the Australia–Asia Collision (eds Hall, R., Cottam, M. A. & Wilson, M. E. J.), pp. 7–35. Geological Society of London, Special Publication no. 355.Google Scholar

Metcalfe, I. 2013. Gondwana dispersion and Asian accretion: Tectonic and palaeogeographic evolution of eastern Tethys. Journal of Asian Earth Sciences 66, 1–33.CrossRefGoogle Scholar

Mo, X., Shen, S., Zhu, Q., Xu, T., Wei, Q., Tan, J., Zhang, S. & Cheng, H. 1998. Volcanics-Ophiolite and Mineralization of Middle-Southern Part in Sanjiang Area of Southwestern China. Geological Publishing House, Beijing (in Chinese with English abstract).Google Scholar

Ozerov, A. Y. 2000. The evolution of high-alumina basalts of the Klyuchevskoy volcano, Kamchatka, Russia, based on microprobe analyses of mineral inclusions. Journal of Volcanology and Geothermal Research 95 (1–4), 65–79.CrossRefGoogle Scholar

Pearce, J. A. & Cann, J. 1973. Tectonic setting of basic volcanic rocks determined using trace element analyses. Earth and Planetary Science Letters 19 (2), 290–300.CrossRefGoogle Scholar

Pichavant, M. & MacDonald, R. 2007. Crystallization of primitive basaltic magmas at crustal pressures and genesis of the calc-alkaline igneous suite: experimental evidence from St Vincent, Lesser Antilles arc. Contributions to Mineralogy and Petrology 154 (5), 535–58.CrossRefGoogle Scholar

Pietruszka, A. J., Hauri, E. H. & Blichert-Toft, J. 2009. Crustal contamination of mantle-derived magmas within Piton de la Fournaise Volcano, Réunion Island. Journal of Petrology 50 (4), 661–84.CrossRefGoogle Scholar

Qi, L., Jing, H. & Gregoire, D. C. 2000. Determination of trace elements in granites by inductively coupled plasma mass spectrometry. Talanta 51 (3), 507–13.Google Scholar

Searle, M. P., Yeh, M. W., Lin, T. H. & Chung, S. L. 2010. Structural constraints on the timing of left-lateral shear along the Red River shear zone in the Ailao Shan and Diancang Shan Ranges, Yunnan, SW China. Geosphere 6 (4), 316–38.CrossRefGoogle Scholar

Shaw, D. M. 1970. Trace element fractionation during anatexis. Geochimica et Cosmochimica Acta 34 (2), 237–43.CrossRefGoogle Scholar

Shen, S. Y., Qirong, W., & Chenghuilan Mo, X. X. 1998 a. Metamorphic peridotite and its rock series in Ailaoshan Belt, Yunnan Province. Chinese Science Bulletin 43 (4), 438–42.Google Scholar

Shen, S. Y., Qirong, W., Huilan, C. & Xuanxue, M. 1998 b. Characteristics of Ophiolites in Ailaoshan Belt, & ‘Sanjiang’ Region. Acta Petrologica et Mineralogica 17 (1), 1–8.Google Scholar

Sisson, T. & Grove, T. 1993. Temperatures and H2O contents of low-MgO high-alumina basalts. Contributions to Mineralogy and Petrology 113 (2), 167–84.CrossRefGoogle Scholar

Sun, S. S. & McDonough, W. F. 1989. Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. In Magmatism in the Ocean Basins (eds Saunders, A. D. and Norry, M. J.), pp. 313–45. Geological Society of London, Special Publication no. 42.Google Scholar

Takahashi, E. 1986. Melting of a dry peridotite Klb-1 up to 14 Gpa - implications on the origin of peridotitic upper mantle. Journal of Geophysical Research: Solid Earth and Planets 91 (B9), 9367–82.CrossRefGoogle Scholar

Tiepolo, M., Bottazzi, P., Foley, S., Oberti, R., Vannucci, R. & Zanetti, A. 2001. Fractionation of Nb and Ta from Zr and Hf at mantle depths: the role of titanian pargasite and kaersutite. Journal of Petrology 42 (1), 221–32.CrossRefGoogle Scholar

Tilley, C. 1950. Some aspects of magmatic evolution. Quarterly Journal of the Geological Society 106 (1–4), 37–61.CrossRefGoogle Scholar

Wagner, T. P., Donnellynolan, J. M. & Grove, T. L. 1995. Evidence of hydrous differentiation and crystal accumulation in the low-MgO, high-Al2O3 Lake basalt from Medicine Lake Volcano, California. Contributions to Mineralogy and Petrology 121 (2), 201–16.CrossRefGoogle Scholar

Wang, B., Wang, L., Chen, J., Yin, F., Wang, D., Zhang, W., Chen, L. & Liu, H. 2013. Triassic three-stage collision in the Paleo-Tethys: Constraints from magmatism in the Jiangda–Deqen–Weixi continental margin arc, SW China. Gondwana Research, published online 27 August 2013. doi: 10.1016/j.gr.2013.07.023.Google Scholar

Wang, X. F., Metcalfe, I., Jian, P., He, L. Q. & Wang, C. S. 2000 a. The Jinshajiang-Ailaoshan Suture Zone, China: tectonostratigraphy, age and evolution. Journal of Asian Earth Sciences 18 (6), 675–90.CrossRefGoogle Scholar

Wang, Y. J., Fan, W. M., Zhang, Y. H., Peng, T. P., Chen, X. Y. & Xu, Y. G. 2006. Kinematics and Ar-40/Ar-39 geochronology of the Gaoligong and Chongshan shear systems, western Yunnan, China: implications for early Oligocene tectonic extrusion of SE Asia. Tectonophysics 418 (3–4), 235–54.CrossRefGoogle Scholar

Wang, Y. J., Zhang, A. M., Fan, W. M., Peng, T. P., Zhang, F. F., Zhang, Y. H. & Bi, X. W. 2010. Petrogenesis of late Triassic post-collisional basaltic rocks of the Lancangjiang tectonic zone, southwest China, and tectonic implications for the evolution of the eastern Paleotethys geochronological and geochemical constraints. Lithos 120 (3–4), 529–46.CrossRefGoogle Scholar

Wang, Y.-Z., Li, X.-L., Duan, L.-L., Huang, Z.-X. & Chui, C. 2000 b. Geotectonics and Metallogeneny in South Nujiang-Lanchang-Jinsha Rivers Area. Beijing: Geologial Publishing House.Google Scholar

Wood, D. A. 1980. The application of a Th-Hf-Ta diagram to problems of tectonomagmatic classification and to establishing the nature of crustal contamination of basaltic lavas of the British Tertiary Volcanic Province. Earth and Planetary Science Letters 50 (1), 11–30.CrossRefGoogle Scholar

Workman, R. K. & Hart, S. R. 2005. Major and trace element composition of the depleted MORB mantle (DMM). Earth and Planetary Science Letters 231 (1–2), 53–72.CrossRefGoogle Scholar

Xiong, X., Adam, J. & Green, T. 2005. Rutile stability and rutile/melt HFSE partitioning during partial melting of hydrous basalt: implications for TTG genesis. Chemical Geology 218 (3), 339–59.CrossRefGoogle Scholar

Xu, Y.-G. 2006. Using basalt geochemistry to constrain Mesozoic–Cenozoic evolution of the lithosphere beneath North China Craton. Dixue Qianyuan/Earth Science Frontiers 13 (2), 93–104.Google Scholar

Yumul, G. P., Zhou, M. F., Wang, C. Y., Zhao, T. P. & Dimalanta, C. B. 2008. Geology and geochemistry of the Shuanggou ophiolite (Ailao Shan ophiolitic belt), Yunnan Province, SW China: evidence for a slow-spreading oceanic basin origin. Journal of Asian Earth Sciences 32 (5–6), 385–95.CrossRefGoogle Scholar

Zhang, Q., Zhou, D. & Li, X. 1995. Characteristics and genesises of Shuanggou ophiolites, Yunnan Province. China Acta Petrol Sin (in Chinese) 11 (Suppl), 190–202.Google Scholar

Zhong, D. 1998. Paleo-Tethyan Orogenic Belt in Western Yunnan and Sichuan. Beijing: Science Press (in Chinese).Google Scholar

Zi, J. W., Cawood, P. A., Fan, W. M., Tohver, E., Wang, Y. J., Mccuaig, T. C. & Peng, T. P. 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 (2), 81–112.CrossRefGoogle Scholar

Zi, J. W., Cawood, P. A., Fan, W. M., Wang, Y. J. & Tohver, E. 2012 a. Contrasting rift and subduction-related plagiogranites in the Jinshajiang ophiolitic melange, southwest China, and implications for the Paleo-Tethys. Tectonics 31, TC2012, doi: 10.1029/2011TC002937.CrossRefGoogle Scholar

Zi, J. W., Cawood, P. A., Fan, W. M., Wang, Y. J., Mccuaig, T. C., & Peng, T. P. 2012 b. Triassic collision in the Paleo-Tethys Ocean constrained by volcanic activity in SW China. Lithos 144, 145–60.CrossRefGoogle Scholar

Zindler, A. & Hart, S. 1986. Chemical geodynamics. Annual Review of Earth and Planetary Sciences 14, 493–571.CrossRefGoogle Scholar