江西省新余太平山铁矿区叠加褶皱构造解析并论恢复复杂褶皱系的包络面的意义

一、概述太平山铁矿区是江西新余铁矿田之一段,整个矿田呈近东西走向展布,东起芳洲,西至枫树下,长约60公里.矿田总体构造为一褶轴向西倾伏,轴面向北倾斜的倒转背斜(神山背斜).该背斜南翼保存完整,而北翼仅在倾伏端处残存.矿田内出露地层主要为震旦系的一套绿片岩相的浅变质岩,铁矿赋存于震旦系上部杨家桥组中.矿石有两种类型,按正常层序上为绿泥磁铁石英岩,下为镜铁磁铁石英岩,顶板为绿泥千枚岩,底板为含磁铁绿泥千枚岩,矿床成因为含铁硅质建造经变质作用而成.矿田以井头东侧断裂为界,分为东西两段,东段地层为倒转层序,西段为正常层序;东段矿层褶皱包络面总体产状倾向北西,而西段则倾向南东.矿田内的岩浆岩,主要有东南侧的城上花岗岩和西南僦的山庄花岗岩,它们同属加里.

A STRUCTURAL ANALYSIS OF SUPER IMPOSED FOLDS AT TAIPINGSHAN IRON MINE, XINYU COUNTY, JIANGXI PROVINCE, AND THE SIGNIFICANCE OF RECONSTRUCTING ENVELOPES IN THE COMPLICATED FOLD SYSTEM

The iron ore horizons and associated stratigraphic units of the studied mine have undergone multiphasic folded deformation.This paper presents a result of structural analysis in the aspect of folded sequence features,the superimposed relations and development mechanism of folds,the regularities of structural deformation and its application in exploration,based on the huge amount of field data.The significance of reconstructing envelopes in the complicated fold system with some concrete examples of using envelopes to judge large strutures,discriminate stratigraphic sequences,conduct geological mapping and assign drilling holes are also discussed.