赣东北地区福泉山岩体高分异S型花岗岩成因:来自锆石U-Pb年龄、Hf同位素及地球化学的证据  

Genesis of highly fractionated S-type granites:Evidence from zircon U-Pb age,Hf isotopes and geochemistry of Fuquanshan pluton,Northeastern Jiangxi Province

作　　者：徐文坦 刘广虎 马虎超 贾旭 张斌斌 张榕 XU Wentan;LIU Guanghu;MA Huchao;JIA Xu;ZHANG Binbin;ZHANG Rong(College of Earth Sciences,Institute of Disaster Prevention,Sanhe 065201,Hebei,China;Hebei Key Laboratory of Earthquake Dynamics,Sanhe 065201,Hebei,China;Jinchuan Group Co.,Ltd.,Jinchang 737100,Gansu,China;School of Geoscience and Techtology,Southwest Petroleum University,Chengdu 610500,Sichuan,China;Hubei Shenlong Geological Engineering Investigation Institute Co.,Ltd.,Wuhan 430100,Hubei,China)

机构地区：[1]防灾科技学院地球科学学院,河北三河065201 [2]河北省地震动力学重点实验室,河北三河065201 [3]金川集团股份有限公司,甘肃金昌737100 [4]西南石油大学地球科学与技术学院,四川成都610500 [5]湖北神龙地质工程勘察有限公司,湖北武汉430100

出　　处：《地质通报》2022年第4期577-589,共13页Geological Bulletin of China

基　　金：国家重点研发计划项目《原位多参量地球化学传感系统检定指标评价及对比试验研究》(编号:2016YFC0303902-04);中国地质调查局项目《钦杭成矿带德兴—歙县地区地质矿产调查》(编号:1212013065500);防灾科技学院2020年度实习基地教学改革项目《芦峰口地区岩浆岩形成时代的精确厘定》。

摘　　要：福泉山岩体位于赣东北地区,为揭示其成因及形成构造背景,对福泉山岩体进行了锆石U-Pb年龄、Hf同位素和全岩地球化学研究。其中锆石LA-ICP-MS定年结果显示,该岩体的形成年龄约为130 Ma,为早白垩世,属燕山晚期岩浆活动的产物。锆石εHf(t)值为-5.47~-1.51,t DM2为1255~1668 Ma。该岩体地球化学特征表现为较高的SiO_(2)(73.45%~74.56%)、富碱(7.61%~7.9%)、富铝(13.22%~13.5%),亏损Ba、Nb、Sr、Ti等元素,较低的稀土元素总量(87.1×10^(-6)~263.9×10^(-6)),并具有负Eu异常,明显的轻稀土元素富集、重稀土元素亏损的右倾分布曲线等特点。结合前人研究成果认为,福泉山岩体为高分异S型花岗岩,形成于古太平洋板块向华南板块俯冲产生的拉张构造背景,为岩石圈地幔上涌导致的中元古代下地壳变沉积岩部分熔融的产物。Fuquanshan pluton is located in the northeast of Jiangxi Province.Geochronology,Hf isotopes and geochemical characteristics of Fuquanshan pluton were studied to reveal the genesis and tectonic setting.LA-ICP-MS dating results suggest that the formation age of Fuquanshan pluton is around 130 Ma,which is the product of Yanshanian magmatism.TheεHf(t)values of zircons range from-5.47 to-1.51 with t DM2 values from 1255 Ma to 1668 Ma,suggesting a Mesoproterozoic source rock.This pluton is characterized by relatively high SiO_(2)(73.45%~74.56%),alkali-rich(7.61%~7.9%),enrichment in aluminum(13.22%~13.5%),loss of Ba,Nb,Sr,Ti,and relatively lowΣREE(87.1×10^(-6)~263.9×10^(-6)),Eu negative anomaly,obviously light rare earth elements enrichment and heavy rare earth elements loss.Combined with the previous research,Fuquanshan pluton was formed under the extensional tectonic background generated by the subduction of the paleo-Pacific plate to South China,and generated by partial melting of Mesoproterozoic lower-crust metasedimentary rocks induced by upwelling of asthenosphere.

关 键 词：早白垩世 S型花岗岩 锆石U-PB年龄 HF同位素 地球化学 赣东北地区 地质调查工程 

分 类 号：P588.12[天文地球—岩石学]