Author(s)

Shen Liu, Ruizhong Hu, Caixia Feng, Shan Gao, Guangying Feng, Youqiang Qi, Tao Wang, Ian M. Coulson, Yuhong Yang, Chaogui Yang

Chengdu University of Technology, Chengdu, China.
Solid Earth Studies Laboratory, Department of Geology, University of Regina, Regina, Canada.
State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan, China.
State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China.

Post-collision felsic rocks in Southeastern Yunnan province contain granodiorites. U-Pb zircon ages, geochemical data and Sr-Nd isotopic data for these rocks are reported in the present paper. Laser ablation inductively coupled plasma mass spectrometry U-Pb zircon analyses yielded consistent age 252.5 ± 1.0 Ma for one sample of the felsic rocks. The granodiorites were characterized by variational and high (⁸⁷Sr/⁸⁶Sr)_i, ranging from 0.7223 to 0.7236 and very low ε_Nd (t) values from –29.1 to –30.4. In addition, these rocks are characterized by slight Eu negative anomalies, Nb, Ta, Ti and Sr negative anomalies on primitive mantle normalization spider. Geochemical and isotopic characteristics suggest that these rocks were derived from an enriched crust source. The granodiorites resulted from the fractionation of potassium feldspar, plagioclase and ilmenite or rutile. However, the granodiorites were unaffected by visible crustal contamination during ascent. As a result, the granodiorites may have been formed due to partial melting of crust-derived sedimentary rocks beneath southeastern Yunnan province, southern China.

Granodiorites; Age; Origin; Southeastern Yunnan Province; Southern China

Liu, S. , Hu, R. , Feng, C. , Gao, S. , Feng, G. , Qi, Y. , Wang, T. , M. Coulson, I. , Yang, Y. and Yang, C. (2012) U-Pb Zircon Age, Geochemical and Sr-Nd Isotopic Constraints on the Age and Origin of the Granodiorites in Guilong, Southeastern Yunnan Province, Southern China. Open Journal of Geology, 2, 229-240. doi: 10.4236/ojg.2012.24023.