%0 Journal Article %T 江西中部新丰街花岗质岩体LA-ICP-MS锆石U-Pb年代学、元素和Sr-Nd-Hf同位素地球化学特征及岩石成因 %A 朱书奇 %A 姜耀辉 %A 王国昌 %A 倪春雨 %A 青龙 %J 高校地质学报 %D 2016 %X 对江西中部新丰街花岗质岩体开展了岩相学、LA-ICP-MS锆石U-Pb年代学以及元素和Sr-Nd-Hf同位素地球化学研 究，并探讨了岩石成因及其构造意义。结果表明，新丰街岩体由二云母花岗岩和黑云母花岗组成；两者均形成于晚侏罗世 （~148 Ma）；二云母花岗岩SiO2含量为75.71%~78.36%，为弱过铝质—强过铝质岩石，属高钾钙碱性系列，Mg#变化于0.26~ 0.34，具有较低的Ga/Al比值（绝大部分<2.6×10-4） 和较低的Zr+Nb+Ce+Y含量（<350×10-6），全岩εNd(t)为-10~-8.2，锆石原 位εHf(t)为-15.7~-9.4；黑云母花岗岩SiO2含量为71.25%~74.41%，主要为准铝质—弱过铝质岩石，也属于高钾钙碱性系列， Mg#变化于0.32~0.37，同样具有较低的Ga/Al比值（绝大部分<2.6×10-4） 和较低的Zr+Nb+Ce+Y含量（<350×10-6），全岩初始 87Sr/86Sr比值为0.7136~0.7153，εNd(t)为-10.0~-8.9，锆石原位εHf(t)值为-16.5~-10.9。通过综合研究认为二云母花岗岩具有S 型花岗岩特征，是由下地壳中变质泥岩在相对较低温度下发生部分熔融而形成的；黑云母花岗岩具有I型花岗岩特征，是由下 地壳中长英质火成岩在相对较高温度下发生部分熔融而形成的。岩体侵位于由古太平洋板块俯冲引起的陆缘弧构造环境。</br>In this study, we present detailed LA-ICP-MS zircon U-Pb chronology, major and trace elements, and Sr-Nd-Hf isotopic data for the Xinfengjie pluton in central Jiangxi province, and discuss its petrogenesis and tectonic implications. Our results show that the Xinfengjie granites are composed of two-mica granites and biotite granites, both of which were formed in late Jurassic (ca. 148 Ma). The two-mica granites have SiO2 contents of 75.71~78.36%. They are weakly peraluminous to strongly peraluminous rocks, and belong to high-K calc-alkaline series. Their Mg# vary from 0.26 to 0.34, and they have low Ga/Al ratios (mostly < 2.6×10-4) and low Zr+Nb+Ce+Y contents (<350×10-6). They have whole-rack εNd(t) of -10~-8.2, and zircon in-situ εHf(t) of -15.7~-9.4. The biotite granites have SiO2 contents of 71.25~74.41% . They are metaluminous to weakly peraluminous rocks, and also belong to high-Kcalc-alkaline series. Their Mg# vary from 0.32 to 0.37, and they also have low Ga/Al ratios (mostly < 2.6×10-4) and low Zr+Nb+Ce+Y contents (<350×10-6). They have initial 87Sr/86Sr ratios of 0.7136~0.7153, εNd(t) of -10.0~-8.9, and zircon in-situ εHf(t ) of -16.5~-10.9. Through our comprehensive research, we consider that the two-mica granites show characteristics of S-type granites, and were formed at lower temperature by partial melting of meta-pelite in the lower crust, while the biotite granites exhibit I-type affinity, and were formed at higher temperature by partial melting of felsic rocks in the lower crust. This pluton emplaced in a continental-arc tectonic regime which was induced by the subduction of the paleo-pacific plate. %K 新丰街岩体 %K 江西中部 %K LA-ICP-MS锆石U-Pb年龄 %K Sr-Nd-Hf同位素 %K S型和I型花岗岩< %K /br> %K Xinfengjie granites %U http://geology.nju.edu.cn/CN/abstract/abstract9789.shtml