Adakite-type sodium-rich rocks in Awulale Mountain of west Tianshan: Significance for the vertical growth of continental crust

  • Xiaolin Xiong
  • Zhenhua Zhao
  • Zhenghua Bai
  • Houjun Mei
  • Yixian Wang
  • Qiang Wang
  • Jifeng Xu
  • Hecai Niu
  • Zhiwei Bao


The sodium-rich dacites and albite porphyries of Permian in the Awulale Mountain of west Tianshan have unique chemical and trace element signatures identical to adakite. These intermediate-acidic igneous rocks are characterized by high Na2O, Al2O3 and Sr contents and high Sr/Y and La/Y ratios (> 40 and > 20, respectively), and low Y and Yb contents, and strong depletion in HREE, and positive Eu anomaly. The (143Nd/144Nd)i is in the range from 0.51236 to 0.51248 and the εNd(t) is positive value (+0.79+3.11); the (87Sr/86Sr)i is in the range from 0.7052 to 0.7054. These Nd and Sr isotopic composition features indicate that the source rocks of these adakite-type rocks are from a weakly depleted mantle, or a depleted mantle, but was contaminated by the crustal materials. These adakite-type rocks were most likely derived from the partial melting of new underplated basaltic rocks under the conditions of amphibolite to eclogite transition in the postcollisional environment of North Xinjiang during the Permian Period. They are not only the Phanerozoic juvenile crust materials, but also are probably animportant symbol of the underplating of mantlederived basaltic magmas and the vertical growth of continental crust in the west Tianshan area during the postcollision of Late Paleozoic.


Awulale adakite-type rocks underplating vertical growth of continental crust 


  1. 1.
    Defant, M. J., Drummond, M. S., Derivation of some modern arc magmas by melting of young subducted lithosphere, Nature, 1990, 347: 662.CrossRefGoogle Scholar
  2. 2.
    Aatherton, M. P., Petford, N., Generation of sodium-rich magmas from newly underplated basaltic crust, Nature, 1993, 362: 144.CrossRefGoogle Scholar
  3. 3.
    Martin, H., Adakitic magmas: modern analogues of Archaean granitoids, Lithos., 1999, 46(3): 411.CrossRefGoogle Scholar
  4. 4.
    Defant, M. J., Drummond, M. S., Potential example of the partial melting of the subducted lithosphere in a volcanic arc, Geology, 1993, 21: 547.CrossRefGoogle Scholar
  5. 5.
    Li, H. Q., Xie, F. C., Chang, H. L., Dating of Metallogenisis of Metal Ore Deposits in North Xinjiang (in Chinese), Beijing: Geological Publishing House, 1998, 195–201.Google Scholar
  6. 6.
    Petford, N., Atherton, M., Na-rich partial melts from newly underplated basaltic crust: the Cordillera Blanca Batholith, Peru, J. Petrology, 1996, 37: 1491.CrossRefGoogle Scholar
  7. 7.
    Martin, H., Effect of steeper geothermal gradient on geochemistry of subduction-zone magmas, Geology, 1986, 14: 753.CrossRefGoogle Scholar
  8. 8.
    Kay, R. W., Aleutian magnesian andesites: Melts from subducted Pacific ocean crust, Journal of Volcanology and Geothermal Research, 1978, 4: 117.CrossRefGoogle Scholar
  9. 9.
    Drummond, M. S., Defant, M. J., A model for trondhjemite-tonalite-dacite genesis and crustal growth via slab melting: Archean to modern comparisons, Journal of Geophysical Research, 1990, 95: 21503.CrossRefGoogle Scholar
  10. 10.
    Kay, S. M., Ramos, V. A., Marquez, M., Evidence in Cerro Pampa volcanic rocks for slab-melting prior to ridge-trench collision in southern South America, The Journal of Geology, 1993, 101: 703.]CrossRefGoogle Scholar
  11. 11.
    Morris, S. P., Slab melting as an explanation of Quaternary volcanism and aseismicity in southwest Japan, Geology, 1995, 23: 395.CrossRefGoogle Scholar
  12. 12.
    Yogodziski, G. M., Kay, R. W., Magnesian andesite in the west Aleutian Komandorsky region: implications for slab melting and pressures in the mantle wedge, Geol. Soc. Am. Bull., 1995, 107: 505.CrossRefGoogle Scholar
  13. 13.
    Stern, C. R., Killian, R., Role of the subducted slab, mantle wedge and continental crust in the generation of adakites from the Andean Austral Volcanic Zone, Contrib. Mineral. Petrol., 1996, 123: 263.CrossRefGoogle Scholar
  14. 14.
    Wang, Y., Zhang, Q., Qian, Q., Geochemical characteristics and structural significance of adakite, Scentia Geologica Sinica, 2000, 35(2): 251.Google Scholar
  15. 15.
    Wang, Q., Xu, J. F., Identification of adakite-type gray gneiss in Dabie Mountain and its relationship with ultra-high-pressure metamorphism, Chinese Science Bulletin (in Chinese), 2000(10): 1017.Google Scholar
  16. 16.
    Peacock, S. M., Rushmer, T., Thompson, A. B., Partial Melting of subducting oceanic crust, Earth Planet. Sci. Lett., 1994, 121: 227.CrossRefGoogle Scholar
  17. 17.
    Rapp, R. P., Watson, E. B., Dehydration melting of metabasalt at 8-32 kbar: Implications for continental growth and crust-mantle recycling, Journal of Petrology, 1995, 36(4): 891.Google Scholar
  18. 18.
    Gromet, L. P., Silver, L., REE variations across the Peninsular Ranges Batholith: Implications for batholithic petrogenesis and crustal growth in magmatic arcs, Journal of Petrology, 1987, 28: 75.Google Scholar
  19. 19.
    Nelson, K. D., Are crustal thickness variations in old mountain belt like the Appalachians a consequence of lithosperic delamination? Geology, 1992, 20: 498.CrossRefGoogle Scholar
  20. 20.
    Rudnick, R. L., Growing from below, Nature, 1990, 347: 711.CrossRefGoogle Scholar
  21. 21.
    Voshage, H., Hofmann, A. W., Mazzucchelli, M., Isotopic evidence from the Ivrea Zone for a hybird lower crust formed by magmatic underplating, Nature, 1990, 347: 731.CrossRefGoogle Scholar
  22. 22.
    Rapp, R. P., Watson, E. B., Miller, C. F., Partial melting of amphibolite/eclogite and the origin of Archean trondhjemites and tonalities, Precambrian Research, 1991, 51: 1.CrossRefGoogle Scholar
  23. 23.
    Xiao, X. C., Tang, Y. C., Hong, Y. M., Geological Structure of North Xinjiang and Its Neighbor Ambitus Area (in Chinese), Beijing: Geological Publishing House, 1992.Google Scholar
  24. 24.
    He, G. Q., Li, M. S., Liu, D. C., Crustal evolution and metallogenisis during Paleozoic era in Xinjiang, China (in Chinese). Urumqi: Xinjiang People’s Publishing House, 1994.Google Scholar
  25. 25.
    Han, B. F., He, G. Q., Wang, S. G., Mantle-derived magmatism, underplating and the nature of basement of Junggar Basin, Science in China, Series D, 1999, 29(1): 16.Google Scholar
  26. 26.
    Han, B. F., Wang, S. G., Jaha, B. M. et al., Depleted-mantle source for the Ulungur River A-type granites from North Xinjiang, China: Geochemistry and Nd-Sr isotopic evidence, and implications for Phanerozoic crustal growth, Chemical Geology, 1997, 138: 135.CrossRefGoogle Scholar
  27. 27.
    Han, B. F., Wang, S. G., Hong, D. W., Metaalumineous-alumineous granite with positive εNd(t): Yebushan Pluton of Xinjiang, Chinese Science Bulletin, 1998, 43(12): 1323.Google Scholar
  28. 28.
    Chen, J. F., Man, F. S., Ni, S. B., Nd and Sr isotopic geochemistry of mafic-ultramafic intrusions from Jingbulake rock belt, west Tianshan Mountains, Xinjiang, Geochimica (in Chinese), 1995, 24, 121.Google Scholar
  29. 29.
    He, B. C., Tan, K. R., The ages and Nd and Sr isotopic compositions of mantle-derived igneous rocks in Jimulaibu gold deposit district of North Xinjiang, 1994, 18: 219.Google Scholar
  30. 30.
    Hopson, C., Wen, J., Tilton, G. et al., Paleozoic plutonism in East Junggar, Bogdashan, and east Tianshan, NW China, EOS Trans. Am. Geophys. Union, 1989, 70: 1403.Google Scholar
  31. 31.
    Zhao, Z. H., Wang, Z. G., Zou, T. L., A discussion on the origin of Wulungur alkalic granites in Xinjiang, Geochimica (in Chinese), 1996, 25: 205.Google Scholar
  32. 32.
    Kwon, S. T., Tilton, G. R., Coleman, R. G. et al., Isotope studies bearing on the tectonics of the West Junggar region, Xinjiang, China, Tectonics, 1989, 8: 719.CrossRefGoogle Scholar
  33. 33.
    Zhou, T. X., Chen, J. F., Li, X. M., The Genesis of granitiods with high εNd(t) in Alatao Mountain of Xinjiang, Scentia Geologica Sinica (in Chinese), 1996, 31: 71.Google Scholar
  34. 34.
    Zhou, Y. Q., Wang, Y. X., Dating and Nd, Sr, O isotope studies of the Chaganhundi granite, Chinese Sci. Bull., 1993, 38(18): 1646.Google Scholar
  35. 35.
    Zhao, Z. H., Wang, Z. G., Zou, T. L., The REE and O, Pb, Sr and Nd compositions and the genesis types of granitoids in Altai Mountain The New Progress of Solid Earth Science in North Xinjiang (ed. Tu, G. C.) (in Chinese), Beijing: Science Press, 1993, 239–266.Google Scholar
  36. 36.
    Zhang, Q. F., Hu, A. Q., Zhang, G. X., Isotopic evidences of Mesozoic and Cenozoic magmatism in Altai Mountain, Geochimica (in Chinese), 1994, 23: 269.Google Scholar
  37. 37.
    Hong, D. W., Wang, S. G., Xie, X. L. et al., Genesis of positive εNd(t) granitoids in the Da Hinggan Mts-Mongolia Orogenic Belt and growth of continental crust, Earth Science Frontiers (in Chinese), 2000, 7(2): 441.Google Scholar
  38. 38.
    Peng, C., Gao, R., The Lithosphere and Rheosphere Structures of China Continent and Near Ocean Area, Beijing: Seismic Publishing House, 2000, p84.Google Scholar
  39. 39.
    Taylor, S. R., Mclennan, S. M., The Continental Crust: Its Composition and Evolution, Oxford: Blackwell, 1985, 312.Google Scholar

Copyright information

© Science in China Press 2001

Authors and Affiliations

  • Xiaolin Xiong
    • 1
    • 2
  • Zhenhua Zhao
    • 1
  • Zhenghua Bai
    • 1
  • Houjun Mei
    • 1
  • Yixian Wang
    • 1
  • Qiang Wang
    • 1
  • Jifeng Xu
    • 1
  • Hecai Niu
    • 1
  • Zhiwei Bao
    • 1
  1. 1.Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhouChina
  2. 2.State Key Laboratory of Mineral Deposit Research of Nanjing UniversityNanjingChina

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