The oldest basement rock in the Yangtze Craton revealed by zircon U-Pb age and Hf isotope composition |
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| Authors: | WenFang Jiao YuanBao Wu SaiHong Yang Min Peng Jing Wang |
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| Institution: | 1.State Key Laboratory of Geological Processes and Mineral Resources, Faculty of Earth Sciences,China University of Geosciences,Wuhan,China;2.State Key Laboratory of Continental Dynamics,Northwest University,Xi’an,China |
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| Abstract: | Here we report an integrated study of zircon U-Pb age and Hf isotope composition for a gneiss sample from the Kongling terrain
in the Yangtze Craton. CL imaging reveals that most zircons are magmatic, and a few of them have thin metamorphic rims. The
magmatic zircons gave a weighted mean U-Pb age of 3218±13 Ma, indicating the gneiss is the oldest basement rock in the Yangtze
Craton found to date. They have ɛ
Hf(t) value of −2.33±0.51, and two-stage Hf model age of 3679±49 Ma, indicating that the gneiss was derived from partial melting
of >3.6 Ga crustal rock. The metamorphic rims yielded an age of 2732±16 Ma, implying that the metamorphic event occurred in
the Neoarchean era, which may be also a major tectono-thermal event in the Yangtze Craton. |
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| Keywords: | Kongling zircon U-Pb age Hf isotope composition oldest basement rock |
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