Exact timing of granulite from the Namche-Barwa, Eastern Himalayan: New Constrains on SIMS U-Pb Zircon Age

Su, Wen and Zhang, Ming and Liu, Jingbo and Liu, Xiaohan and Liu, Xin and Kai, Ye (2012) Exact timing of granulite from the Namche-Barwa, Eastern Himalayan: New Constrains on SIMS U-Pb Zircon Age. International Journal of Earth Sciences, 101 (1). pp. 239-252. ISSN 1437-3254 (Print) 1437-3262 (Online) DOI 10.1007/s00531-011-0656-0

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Abstract

Zircon grains separated from 2 granulites from the eastern Himalaya were investigated by Raman spectroscopy, cathodoluminescence imaging, and secondary ion mass spectrometry. These grains have a thin homogeneous rim and an oscillatory inner zone domain with or without a relict inherited core. Garnet, kyanite, and rutile inclusions were identified within only the rim domain of zircon grains, indicating that the rim had formed during peak granulite-facies metamorphism. U–Pb zircon data record three distinct age populations: 1,805 Ma (for the inherited core), ca. 500 Ma (oscillatory inner zone), as well as 24–25 Ma and ca. 18 Ma (for the metamorphic rim). These new precision ages suggest that the peak metamorphic age for the HP granulite is at ca. 24–25 Ma, and subsequent amphibolite-facies retrograde metamorphism occurred at ca. 18 Ma.

Item Type: Article
Uncontrolled Keywords: 2011AREP; IA62;
Subjects: 03 - Mineral Sciences
Divisions: 03 - Mineral Sciences
Journal or Publication Title: International Journal of Earth Sciences
Volume: 101
Page Range: pp. 239-252
Identification Number: 10.1007/s00531-011-0656-0
Depositing User: Sarah Humbert
Date Deposited: 11 Mar 2011 17:53
Last Modified: 23 Jul 2013 10:02
URI: http://eprints.esc.cam.ac.uk/id/eprint/2033

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