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SHRIMP U-Pb zircon ages for the UHP metamorphosed granitoid gneiss in Altyn Tagh and their geological significance.
- Source :
-
Chinese Science Bulletin . Dec2004, Vol. 49 Issue 23, p2527-2532. 6p. 1 Chart, 2 Graphs. - Publication Year :
- 2004
-
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. SHRIMP 206pb/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. The 206pb/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. [ABSTRACT FROM AUTHOR]
- Subjects :
- *CATHODOLUMINESCENCE
*LUMINESCENCE
*ZIRCON
*GEOLOGY
*EARTH sciences
Subjects
Details
- Language :
- English
- ISSN :
- 10016538
- Volume :
- 49
- Issue :
- 23
- Database :
- Academic Search Index
- Journal :
- Chinese Science Bulletin
- Publication Type :
- Academic Journal
- Accession number :
- 16687456
- Full Text :
- https://doi.org/10.1360/03wd0502