湘南荷花坪花岗斑岩锆石LA-MC-ICP-MS U-Pb年龄、Hf同位素制约及地质意义  

Zircon U-Pb Geochronology and Hf Isotopic Compositions of Hehuaping Granite Porphyry,Southern Hunan Province,and its Geological Significance

作　　者：章荣清[1] 陆建军[1] 朱金初[1] 姚远[1] 高剑峰[1] 陈卫锋[1] 招湛杰[1] 

机构地区：[1]内生金属矿床成矿研究国家重点实验室南京大学地球科学与工程学院,南京210093

出　　处：《高校地质学报》2010年第4期436-447,共12页Geological Journal of China Universities

基　　金：中国地质调查局调查项目"南岭重要金属矿床成矿机理研究和找矿潜力预测"(1212010632100);国家自然科学基金(40730423;40873029);"深部探测技术与实验研究专项"(Sino Probe-03-01-4D)

摘　　要：荷花坪花岗斑岩位于王仙岭岩体的东南侧,与花岗斑岩有关的矿床主要有锡石硫化物型锡矿、斑岩型锡矿和破碎带蚀变岩型锡矿三种类型。花岗斑岩中锆石的LA-MC-ICP-MS年代学研究表明,其U-Pb年龄为154～156Ma,加权平均值为(154.7±0.5)Ma(MSWD=0.085,n=21),显示为燕山早期侵位。锆石Lu-Hf同位素原位分析结果表明,176Hf/177Hf比值在0.282403～0.282597之间,εH(ft)值介于-2.84～-10.14之间,峰值在-6.5左右,Hf同位素二阶段模式年龄(tDM2)在1.38Ga到1.84Ga之间,峰值在1.55Ga左右,指示岩浆为壳幔混合来源。结合区域内同期锡成矿花岗岩中的继承锆石年龄信息,认为含锡成矿花岗质岩石可能来源于中元古代基底的重熔。The Hehuaping granite porphyry is located to the southeast of Wangxianling granite and there are cassiterite-sulfide type,porphyry type and altered fragmented-rock type tin deposits related to granite porphyry.Zircon LA-MC-ICP-MS U-Pb age for granite porphyry is 154~156 Ma,with a weighted mean age of（154.7±0.5）Ma（MSWD=0.085,n=21）,which suggests an early Yanshanian emplacement.The in situ Hf isotope analysis reveals 176 Hf/ 177 Hf ratios from 0.282403 to 0.282597,andεHf（t）from -2.84 to-10.14（peak value around-6.5）,and the two stage Hf model ages（tDM2）ranging from 1.38 Ga to 1.84 Ga（peak value around 1.55 Ga）,which indicates that its parental magma was derived from the mixed sources of the lower crust and mantle.Based on several age data of inherited zircons from the tin-bearing granites in the neighbouring Nanling Range,it can be concluded that the granitoids related to tin deposits were mainly products of remelting of the Mesoproterozoic basement rocks.

关 键 词：锆石U-Pb年龄 HF同位素 花岗斑岩 荷花坪 

分 类 号：P597.1[天文地球—地球化学] P597.3[天文地球—地质学]