The oldest basement rock in the Yangtze Craton revealed by zircon U-Pb age and Hf isotope composition  

作　　者：JIAO WenFang WU YuanBao YANG SaiHong PENG Min WANG Jing 

机构地区：[1]State Key Laboratory of Geological Processes and Mineral Resources,Faculty of Earth Sciences,China University of Geosciences,Wuhan 430074,China [2]State Key Laboratory of Continental Dynamics,Northwest University,Xi’an 710069,China

出　　处：《Science China Earth Sciences》2009年第9期1393-1399,共7页中国科学（地球科学英文版）

基　　金：Supported by National Natural Science Foundation of China (Grant Nos. 40772042, 90714010, 40873043 and 40821061);the Ministry of Education of China (Grant Nos. IRT0441, B07039 and NCET-06-0659);the Opening Foundation of the State Key Laboratory of Continental Dynamics, Northwest University

摘　　要：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 εHf(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.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 ? 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.

关 键 词：Kongling ZIRCON U-PB age Hf ISOTOPE COMPOSITION oldest BASEMENT rock 

分 类 号：P597.3[天文地球—地球化学]