Sr, Nd and O isotope geochemistry of the mafic-ultramafic complexes in the southern margin of the Altay orogenic belt and discussion of their sources

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• 作者：Zhaochong Zhang (1) (2)
  Fengmei Chai (2)
  Shenghao Yan (3)
  Bailin Chen (4)
  Lixin He (5)
  Yongsheng He (5)
  Gang Zhou (5)
  
• 关键词：mafic ; ultramafic complex ; Sr ; Nd and O isotopes ; source region ; Altay orogenic belt
• 刊名：Frontiers of Earth Science
• 出版年：2007
• 出版时间：February 2007
• 年：2007
• 卷：1
• 期：1
• 页码：44-48
• 全文大小：561KB
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  14. Yang W P, Zhou G, Zhang Z C, et al (2003). Geochemistry of the mafic complexes in the south margin of the Altay orogenic belt and potential of Cu-Ni sulfide deposits. Chinese Bulletin of Geology, 23(4): 390-99 (in Chinese with English abstract)
  15. Ye Q T, Fu X J, Wang B L (1998). Metallogeny of polymetallic metallogenic belts on the southern margin of the Altay Mountains, Xinjiang, China. Acta Geologica Sinica, 72(4): 349-57 (in Chinese with English abstract)
  16. Zhang Z C, Yan S H, Chen B L, et al (2003). Geochemistry of the Kalatongke basic complex in Xinjiang and its constraints on genesis of the deposit. Acta Petrologica et Mineralogica, 22(3): 217-24 (in Chinese with English abstract)
  
• 作者单位：Zhaochong Zhang (1) (2)
  Fengmei Chai (2)
  Shenghao Yan (3)
  Bailin Chen (4)
  Lixin He (5)
  Yongsheng He (5)
  Gang Zhou (5)
  
  1. State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing, 100083, China
  2. Institute of Geology, Chinese Academy of Geological Sciences, Beijing, 100037, China
  3. Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing, 100037, China
  4. Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, 100081, China
  5. No. 4 Geological Party, Xinjiang Bureau of Geology and Resources, Altay, 836500, China
  
• ISSN：2095-0209

文摘

The Sr, Nd and O isotopic compositions of the Kalatongke and Xibodu mafic-ultramafic complexes from the southern margin of the Altay orogenic belt show that they have similar isotopic compositions, characterized by low (87Sr/86Sr), and high ε Nd(t) values (6.3-.1). It suggests that they were derived from a depleted asthenospheric mantle. However, most of the samples have δ 18O values >6-(5.4‰-0.2-, indicating crustal contamination. A combination of Sr and O isotopic data shows the incorporation of crustal materials into the depleted mantle. They were produced by the melting of depleted mantle by the incorporation of subducted oceanic crust, and this incorporation might have occurred in the Early Paleozoic in the light of their Nd model ages and regional tectonics. The Kalatongke complex might have undertaken the contamination of the upper crust whereas the Xibodu complex does not have any signature of contamination of the upper crust. In addition, the similarities of the sources of the two complexes, which were located at the northern and southern sides of the regional Irtysh fault zone respectively, suggest that this fault might not be the boundary between the Altay and Junggar orogenic belts.