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Chinese Science Bulletin

, Volume 49, Issue 23, pp 2527–2532 | Cite as

SHRIMP U-Pb zircon ages for the UHP metamorphosed granitoid gneiss in Altyn Tagh and their geological significance

  • Anda Zhang
  • Liang Liu
  • Yong Sun
  • Danling Chen
  • Yan Wang
  • Jinhai Luo
Articles

Abstract

Cathodoluminescence (CL) and mineral inclusions investigations show that zircons from Yinggelisayi UHP metamorphosed granitoid gneiss in Altyn Tagh exhibit core-mantle-rim internal texture with magmatic residual core, the metamorphic overgrowth mantle and the late stage rim. SHRIMP206Pb/238U ages of 5 spots from the mantles vary from 484±11 to 491±12 Ma with Th/U ratios from 0.01 to 0.03, yielding a weighted average age of 487±10 Ma (2σ) as the age of the UHP metamorphosed granitoid gneiss. The206Pb/238U ages from the oscillatory zoned cores range from 809±19 to 885±21 Ma with Th/U ratios ranging from 0.42 to 0.83, which are interpreted as the crystallization age of the protolith of the granitoid gneiss. The metamorphic age (487±10 Ma) of the UHP metamorphosed granitoid gneiss, well consistent with the peak metamorphic age (about 500 Ma) of the UHP eclogite with crystallization age of the protolith between 809±19 and 885±21 Ma at Jianggelisayi in western Altyn Tagh, indicates the existence of a UHPM belt along the south margin of the Altyn Tagh as a result of deep subduction during Early Paleozoic age of previously existing continental crust.

Keywords

Altyn Tagh UHP metamorphosed granitoid gneiss zircon SHRIMP dating metamorphic age 

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Copyright information

© Science in China Press 2004

Authors and Affiliations

  • Anda Zhang
    • 1
  • Liang Liu
    • 1
  • Yong Sun
    • 1
  • Danling Chen
    • 1
  • Yan Wang
    • 1
  • Jinhai Luo
    • 1
  1. 1.Key Laboratory of Continental Dynamics of the Ministry of Education and Department of GeologyNorthwest UniversityXi’anChina

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