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Science in China Series D: Earth Sciences

, Volume 42, Issue 2, pp 113–119 | Cite as

Postcollisional mantle-derived magmatism, underplating and implications for basement of the Junggar Basin

  • Baofu Han
  • Guoqi He
  • Shiguang Wang
Article

Abstract

The late Paleozoic postcollisional granitoids, mafic-ultramafic complexes, and volcanic rocks are extensively distributed around the Junggar Basin; they are generally characterized by positive εNd(t) values, implying that the magmas were mantle-derived and contaminated with crustal materials to some extents. The emplacement of mantle-derived magmas and their differentiates in the upper crust is the expression of deep geological processes at shallow level, while much more mantle-derived magmas were underplated in the lower crust and the region near the crust-mantle boundary, being component part of basement of the Junggar Basin. The postcollisional mafic-ultramafic complexes would not be generated by re-melting of residual oceanic crust, which was considered as the basement of the Junggar Basin, unless very high degrees of partial melting occurred. Even if old continental crust had been present before collision, it would have been strongly modified by the mantle-derived magma underplating. This interpretation is compatible with the existing geophysical data.

Keywords

depleted mantle postcollisional magmatism underplating basement Junggar Basin 

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Copyright information

© Science in China Press 1999

Authors and Affiliations

  • Baofu Han
    • 1
  • Guoqi He
    • 1
  • Shiguang Wang
    • 1
  1. 1.Department of GeologyPeking UniversityBeijingChina

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