Strongly peraluminous granites of Mesozoic in Eastern Nanling Range, southern China: Petrogenesis and implications for tectonics  

作　　者：SUN Tao, ZHOU Xinmin, CHEN Peirong, LI Huimin, ZHOU Hongying, WANG Zhicheng & SHEN Weizhou Department of Earth Sciences, Nanjing University, Nanjing 210093, China Tianjin Institute of Geology and Mineral Resources, China Geological Survey, Tianjin 300170, China 

出　　处：《Science China Earth Sciences》2005年第2期165-174,共10页中国科学（地球科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No.40132010 and 40072025).

摘　　要：The strongly peraluminous granites (SPGs) of Eastern Nanling Range (ENR) are a characteristic of all bearing highly aluminous minerals, such as muscovite±AI-rich biotite± tourmaline±garnet, and lack of cordierite. In respect of petrography, geochemistry, Nd isotope, and single grain zircon U-Pb dating, the representative granite bodies of them are studied. The research shows that these granites were emplaced in two stages, namely 228-225 Ma BP and J2-3 159-156 Ma BP, belonging to Indosinian and early Yanshanian periods, respectively, and they have low εNd(t) values (-10.6--11.1), high A/CNK, Rb/Sr ratios and tDM values (1887-1817 Ma), and REE's tetrad effect (TE1,3=1.13-1.34). In comparison with related geology, petrology and chronology of granites in adjacent regions, it is suggested that Indosinian SPGs of ENR formed in the circumstance of post-collisional extension 20 Ma after the major collision of Indosinian Movement (258-243 Ma BP) in Indo-China Peninsula, and early Yanshanian SPGs formed in the background of back-arc extension setting controlled by paleo-Pacific tectonic domain, and J1, the interval of two stages, is the interim from Tethyan to Pacific tectonic domains in South China. These SPGs have similar geological and geochemical characteristics, because they all crystallized from the magma of partial melting of early Proterozoic metasedimentary rocks when the thickened crust (≤50 km) became thinning, decompression, and transmitting of water.The strongly peraluminous granites (SPGs) of Eastern Nanling Range (ENR) are a characteristic of all bearing highly aluminous minerals, such as muscovite±Al-rich biotite±tourmaline±garnet, and lack of cordierite. In respect of petrography, geochemistry, Nd isotope, and single grain zircon U-Pb dating, the representative granite bodies of them are studied. The research shows that these granites were emplaced in two stages, namely 228－225 Ma BP and J2－3 159－156 Ma BP, belonging to Indosinian and early Yanshanian periods, respectively, and they have low εNd(t) values (-10.6－-11.1), high A/CNK, Rb/Sr ratios and tDM values (1887－1817 Ma), and REE's tetrad effect (TE1, 3=1.13－1.34). In comparison with related geology, petrology and chronology of granites in adjacent regions, it is suggested that Indosinian SPGs of ENR formed in the circumstance of post-collisional extension 20 Ma after the major collision of Indosinian Movement (258－243 Ma BP) in Indo-China Peninsula, and early Yanshanian SPGs formed in the background of back-arc extension setting controlled by paleo-Pacific tectonic domain, and J1, the interval of two stages, is the interim from Tethyan to Pacific tectonic domains in South China. These SPGs have similar geological and geochemical characteristics, because they all crystallized from the magma of partial melting of early Proterozoic metasedimentary rocks when the thickened crust (≤50 km) became thinning, decompression, and transmitting of water.

关 键 词：NANLING Range  strongly PERALUMINOUS granite  PETROGENESIS of granite  South China. 

分 类 号：P588.121[天文地球—岩石学]