赣北程浪断裂带的形成:程浪超基性岩墙群和星子花岗岩的地球化学证据  

The Forming and Evolution of Chenglang Fault, Northern Jiangxi: Evidences from Geochemical Analyses of Chenglang Ultrabasic Dykes and Xingzi Granites

作　　者：汪昌亮[1] 丛卫克 颜丹平[1] 周美夫[3] 董铁柱[1] 朱忠[1] 卞雄飞[4] 

机构地区：[1]中国地质大学地质过程与矿产资源国家重点实验室 [2]中国核工业地质局,北京100046 [3]香港大学地球科学系 [4]沈阳地质矿产研究所,辽宁沈阳110032

出　　处：《现代地质》2005年第3期325-333,共9页Geoscience

基　　金：国家自然科学基金项目(40472106;40434011;40172070)。

摘　　要：对侵位于彭庐地块东南边缘与程浪断裂带毗邻的前寒武纪花岗岩和出露于程浪深断裂带内的超基性岩墙群的微量元素地球化学特征进行了研究,结果表明前者属板内与岛弧环境的过渡类型,后者代表典型的火山岛弧环境。结合前人在区域构造和地质年代学的研究成果,认为晋宁运动时期,扬子板块东南缘散布着多个小型块体,在华夏板块向扬子板块方向的俯冲过程中,障公山地块先与彭庐地块沿程浪断裂带发生拼合,同时形成程浪超基性岩墙群;与此同时,彭庐地块内则表现为大规模的岩浆侵入作用。在各小型块体陆续发生碰撞后,扬子板块与华夏板块在晋宁运动晚期最终碰撞拼合,火山岛弧环境转换为造山带构造,因此,彭庐地块、障公山地块等火山岛弧均成为华南造山带的组成部分。Penglu and Yangtze Plate from the Zhanggongshan micro-blocks occurred in the Huanan orogenic belt, which separated the Cathaysia Plate. The Chenglang fault separated the Penglu micro-block to the west from the Zhanggongshan micro-block to the east. However, when and how the Penglu and Zhanggongshan microblocks joined together still leave unsolved. Samples from Pre-cambrian granites in Xingzi metamorphic dome which were nearby the Chenglang fault zone and ultrabasic dykes intruded along the Chenglang fault were collected and analyzed with ICP-MS methods. Variable trace element discrimination diagrams indicate a continental environment for Xingzi granites and volcanic-island arc environment for the ultrabasic dyke. The formation of structural styles and geochronological data suggest a volcanic arc formed between the Zhanggongshan and Penglu micro-blocks, and this volcanic arc was produced by the northwestward subduction of Zhanggongshan microblock underneath the Penglu micro-block. It is inferred that where after the collision of the Yangtze and Cathaysia plates, formed the Huanan orogenic belt, and involved in these earlier micro-blocks.

关 键 词：扬子板块 华夏板块 彭庐地块 障公山地块 超基性岩墙 星子花岗岩 程浪断裂带 赣北 

分 类 号：P588.1[天文地球—岩石学] P54[天文地球—地质学]