Geochemical and geochronological studies of the Aketas granite from Fuyun County, Xinjiang: the implications of the petrogenesis and tectonic setting  

作　　者：Xiaofeng Wei Xin Zhang Jiuhua Xu Rufu Ding Guorui Zhang Yong Tang 

机构地区：[1]University of Science and Technology Beijing [2]Beijing Institute of Geology for Mineral Resources [3]Key Laboratory of High-temperature and High-pressure Study of the Earth’s Interior, Institute of Geochemistry,Chinese Academy of Sciences

出　　处：《Chinese Journal Of Geochemistry》2015年第4期579-591,共13页中国地球化学学报

基　　金：financially supported by the Mineral Prospecting and Assessment project, CGS (1212011085020);the National Nature Science Foundation of China (40972066)

摘　　要：As the wall rock of the Aketas gold deposit,the Aketas granite is about 45 km away from Fuyun County, Xinjiang Province. The zircon weighted mean U–Pb age of the Aketas granite is 309.0 ± 4.7 Ma, indicating that the Aketas granite was emplaced during the late Carboniferous. The Aketas granite belongs to the High-K calcalkaline series, with Si O2 content from 63.00 to 68.20 %,K2 O content from 3.06 to 4.49 % and Na2 O content from4.14 to 6.02 %. The Alkaline Ratio(AR) of the Aketas granite is high, from 1.89 to 3.47, and is 2.95 on average.The Aketas granite has lowPREE(92.42–122.73 ppm)and highPLREE/PHREE ratios(6.54–11.88). For the trace elements, the Aketas granite is enriched in LILE(Rb,U, Th, K) and incompatible elements, and marked depleted in HFSE(Nb, Ta, P, Ti). The geochemical characteristics of the Aketas granite suggest that it is a typical I-type and volcanic arc granite, and that the crystallization of clinopyroxene and hornblende is notable during the magmatic evolution. In combination with the regional tectonic studies, we propose that the emplacement of the Aketas granite implies the Altai and East Junggar area was still dominated by a subduction system at *309 Ma.As the wall rock of the Aketas gold deposit,the Aketas granite is about 45 km away from Fuyun County, Xinjiang Province. The zircon weighted mean U–Pb age of the Aketas granite is 309.0 ± 4.7 Ma, indicating that the Aketas granite was emplaced during the late Carboniferous. The Aketas granite belongs to the High-K calcalkaline series, with SiO2 content from 63.00 to 68.20 %,K2O content from 3.06 to 4.49 % and Na2O content from4.14 to 6.02 %. The Alkaline Ratio（AR） of the Aketas granite is high, from 1.89 to 3.47, and is 2.95 on average.The Aketas granite has low ∑REE（92.42–122.73 ppm）and high∑LREE/∑HREE ratios（6.54–11.88）. For the trace elements, the Aketas granite is enriched in LILE（Rb,U, Th, K） and incompatible elements, and marked depleted in HFSE（Nb, Ta, P, Ti）. The geochemical characteristics of the Aketas granite suggest that it is a typical I-type and volcanic arc granite, and that the crystallization of clinopyroxene and hornblende is notable during the magmatic evolution. In combination with the regional tectonic studies, we propose that the emplacement of the Aketas granite implies the Altai and East Junggar area was still dominated by a subduction system at ＊309 Ma.

关 键 词：花岗岩 地球化学 同位素年代学 富蕴县 构造背景 新疆 高钾钙碱性系列 成因 

分 类 号：P597.3[天文地球—地球化学] P588.121[天文地球—地质学]