甘肃北山野马泉岩体同位素地球化学特征  

Isotopic Geochemical Characteristics of Yemaquan Granitic Intrusions in Beishan Area, Gansu Province

作　　者：范洪海 闵茂中[2] 陈佳[2] 季瑞利[1] 

机构地区：[1]核工业北京地质研究院,北京100029 [2]南京大学地球科学系,江苏南京210093

出　　处：《地球学报》2005年第B09期78-83,共6页Acta Geoscientica Sinica

摘　　要：Nd、Sr、Pb同位素研究结果揭示：甘肃北山野马泉岩体第Ⅰ、Ⅱ侵入阶段花岗岩类具有Ⅰ-型花岗岩的特征，（^87Sr／^86Sr）i=0．708-0．710，εNd=-2．229--5．866，在^207Pb／^204Pb-^206Pb／^204Pb构造模式图上其投影点落在造山带演化线附近，在εNd-εSr图解中，其投影点落入Ⅰ-型花岗岩类范围内，其成岩物质为壳幔混合来源。笫Ⅲ侵入阶段的岩石成因类型为S型，其（^87Sr／^86Sr）i=0．7149-0．7358，εNd=-7．3750--8．9556。该岩体形成的地球动力学环境是北山陆内碰撞造山带。Sm-Nd-Pb isotope compositions reveal that Ⅰ-type granite characteristics of the Ⅰ, ⅡYemaquan intrusions are as follows： （^87Sr/^86Sr）i = 0. 708-0. 710, εNd = - 2. 2291 -- 5. 8664 , and the plot of ^207Pb/^204Pb versus ^206Pb/^204Pb iS near and below the evolutionary curve of the orogenic belt. The granitoids are characterized by mixed （crust ＋ mantle） origin of rock-forming materials. The III granitoid is S-type granite,whose （^87Sr/^86Sr）; are 0. 7149-0. 7358 and εNd are - 7. 3750 -- 8. 9556. The geodynamic environment of the granitoids was the Beishan orogenic belt related to intercontinental collision, especially at the time when collision was drawing to its end.

关 键 词：Nd Sr PB同位素 岩石成因 野马泉岩体 甘肃北山 同位素地球化学特征 岩体 野马 地球动力学环境 

分 类 号：P597[天文地球—地球化学] TL942.211[天文地球—地质学]