佳木斯地块西缘太平沟地区蛇绿岩的发现及其构造意义  

DISCOVER OF THE OPHIOLITE IN TAIPINGGOU AREA ON THE WESTERN MARGIN OF JIAMUSI MASSIF: Tectonic implication

作　　者：刘桂香[1] 赵广江 李永胜 

机构地区：[1]沈阳地质矿产研究所,辽宁沈阳110034 [2]黑龙江省第四地质勘察院,黑龙江哈尔滨150036 [3]黑龙江省区域地质调查所,黑龙江哈尔滨150080

出　　处：《地质与资源》2012年第1期51-58,共8页Geology and Resources

基　　金：中国地质调查局"1:25万乌云镇;嘉荫县;太平沟幅区域地质调查"项目(200313000035)资助

摘　　要：在进行1∶25万嘉荫县和太平沟幅区调填图时,首次在太平沟地区发现蛇绿岩的存在.太平沟蛇绿岩出露在黑龙江省东部佳木斯地块西侧,牡丹江-嘉荫断裂以东,呈NE向展布于中元古界黑龙江岩群之中,并与其呈构造接触.蛇绿岩由超镁铁质岩类蛇纹岩、蛇纹石化橄榄辉石岩和变基性岩等组成.太平沟蛇绿岩是松嫩地块-佳木斯地块裂解的产物.蛇绿岩可能来源于俯冲带附近的由小型扩张中心形成的次生洋壳,具有LREE略富集的P-MORB特征,Nd、Ta的负异常,可能与俯冲作用有关.太平沟蛇绿岩的发现,对于研究黑龙江省东部元古宙板块构造、佳木斯地块的形成与演化提供了构造动力学信息,对寻找与地幔有关的金属矿产具有指导意义.Ophiolite was firstly found in Taipinggou area during the 1：250 000 regional geological survey of Jiayin and Taipinggou sheets. It occurs in the west of Jiamusi massif in Eastern of Heilongjiang Province, on the east of Mudanjiang- Jiayin fault. The rock belt, extending in northeast direction, is distributed in and structurally bounded by the Mesoproterozoic Heilongjiang rock group. The ophiolite series is composed of uhramafic serpentinite, serpentinized peridotite-pyroxenite and metamorphosed basic rocks. The Taipinggou ophiolite belt was formed by the splitting of Jiamusi-Songnen massif. The ophiolite might be derived from the secondary oceanic crust formed in the minor spreading center near the subduction zone. Its character of P-MORB of slight LREE enrichment, with negative abnormity of Nd and Ta, suggests that the ophiolite be related to the subduction. The discovery of Taipinggou ophiolite provides new tectonic evidences for the study on the forming and evolving of the Proterozoic plate and Jiamusi massif. It is a significant guide to search mantle-related metal minerals in the region.

关 键 词：蛇绿岩 古洋壳 地块形成与演化 太平沟 黑龙江省 

分 类 号：P588.3[天文地球—岩石学]