辽宁盘岭矿集区花岗岩锆石SHRIMP U-Pb年龄、Hf同位素组成及地质意义  

Zircon SHRIMP U-Pb Age and Hf Isotope of Granite in Panling Ore Concentration Area in Liaoning and Its Geological Significance

作　　者：杨凤超[1,2] 宋运红[1] 赵玉岩[3] 

机构地区：[1]中国地质调查局沈阳地质调查中心,沈阳110034 [2]吉林大学地球科学学院,长春130061 [3]吉林大学地球探测科学与技术学院,长春130026

出　　处：《吉林大学学报（地球科学版）》2017年第5期1429-1441,共13页Journal of Jilin University：Earth Science Edition

基　　金：中国地质调查局国土资源大调查项目(12120113058800;1212011085280;DD20160049)~~

摘　　要：辽宁盘岭矿集区产出在辽吉裂谷中段的草河口—草河城—黑峪一带,是一处典型的古元古代沉积盆地和多金属矿集区。矿区内发育有早白垩世的北大砬子岩体和古元古代高丽墩台岩体,与本区的矿化作用密切相关。北大砬子岩体锆石SHRIMP U-Pb年龄加权平均值为(123.9±2.2)Ma,高丽墩台岩体锆石SHRIMP U-Pb年龄加权平均值为(1 872±13)Ma。北大砬子岩体εHf(0)为负值,εHf(t)为负值(-16.86^-10.95),说明北大砬子岩体形成时壳源物质成分占主导地位,单阶段Hf模式年龄(TDM)平均为1 339 Ma,两阶段Hf模式年龄(TDMC)平均为2 043 Ma;高丽墩台岩体εHf(0)为负值,εHf(t)为正值(0.29~4.64),说明高丽墩台岩体形成时壳源物质成分占主导地位,并有地幔物质混染,单阶段Hf模式年龄(TDM)平均为2 171 Ma,两阶段Hf模式年龄(TDMC)平均为2 355 Ma。结合岩石地球化学特征得出:北大砬子岩体具有高钾钙碱性岩浆岩特征,为较高分异的过铝质I型花岗岩,是底侵岩浆提供热动力使下地壳物质部分熔融的产物,属于晚中生代大陆边缘岩浆弧环境,其与进入早白垩世古太平洋板块俯冲作用密切相关,岩浆活动直接影响盘岭矿集区内一期铜、铅、锌、钼等矿化作用;高丽墩台岩体具有低钾(拉斑)岩浆岩特征,为较高分异的过铝质I型花岗岩,是热的玄武质熔体加热下地壳使之熔融的产物,且可能有地幔物质贡献,岩体侵入诱发的一系列断裂(包括层间断裂)控制着矿集区内矿脉及岩脉的空间分布。The Panling ore concentration area is a typical paleoproterozoic sedimentary basin and a multi-metal ore-concentrated area, located in the zone of Caohekou-Caohecheng-Heiyu, also in the middle section of Liaoning-Jilin rift. The Beidalazi rock developed in the Early Cretaceous and the Gaoliduntai rock developed in Paleoproterozoic are closely related with the mineralization in this ore- concentrated area. The weighted average of the zircon SHRIMP U- Pb age of the Beidalazi rock is （123.9±2.2） Ma, and the weighted average of the zircon SHRIMP U -Pb age of the Gaoliduntai rock is （1 872±16） Ma. The εHf（0） value of the Beidalazi rock is negative, and the εHf（t） is （-16.86 - -10.95）, that indicate its shell material domination when the Beidalazi rock formed. The single stage Hf model age （TDM） is 1 339 Ma, and the two-stage Hf model age （TDMc） is 2 043 Ma. The εHf （0） value of Gaoliduntai rock is negative, and the εHf （t） is 0.29 -4.64, that indicate the shell material domination when the Gaoliduntai rock formed. The single stage Hf model age （TDM） is 2 171 Ma, and the two-stage Hf model age （TDMc） is 2 355 Ma. The geochemical results show that： The Beidalazi rock is of high-K calc-alkaline series and highly differentiated aluminous I- type granite, and it is a thickened and molten product of the lower crust with a serious magma contamination in the Late Mesozoic continental margin magmatic arc environment resulted from the Early Cretaceous subduction of the paleo Pacific plate; The magmatic activity directly led to the mineralization of copper, lead, zinc and molybdenum etc. in Panling area. While the Gaoliduntai rock is a kind of low potassium magmatite （tholeiitic） and highly differentiated aluminous I- type granite caused by the melting of the basaltic melt to heat the crust to melt, and it may have the contribution of mantle material invasion induced by a series of faults （including interqayer fractures） to control the mineralization and distribution of

关 键 词：辽宁盘岭矿集区 花岗岩 锆石SHRIMP U-PB年龄 HF同位素 早白垩世 古元古代 

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