黔中隆起洋水背斜及其As、Sb、Au、Ag低温成矿元素背景特征研究

发布时间：2018-01-29 19:34

本文关键词： 洋水背斜构造解析构造样式元素富集　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：为了探究黔中隆起洋水背斜的构造属性与区域内大规模低温成矿的物质基础之间的联系,本文通过详细野外地质调查、文献综合整理、构造解析以及全岩地球化学微量分析和电子探针分析,确定了洋水背斜的构造样式、变形序列、期次及成因,并在此基础上,对洋水背斜与低温成矿元素Sb、As、Ag、Au丰度异常关系进行了讨论。本文主要取得以下主要成果:1)详细解剖了洋水背斜构造特征及其形成过程。通过对切割洋水背斜的3条横剖面和1条纵剖面的构造解析,厘定出了3期构造变形,即D1期E-W向纵弯褶皱、D2期N-S向纵弯褶皱以及D3期后期挤压叠加改造。综合构造解析结果表明,洋水背斜形成过程为印支期N-S向褶皱(D2期)横跨叠加于加里东E-W向褶皱(D1期)之上,最后经过燕山期后期挤压叠加改造(D3期)定型。2)厘定了低温成矿元素异常层位,并初步确定其赋存状态。地球化学分析表明,区内除新元古界板溪群Au的含量相对于扬子板块上地壳平均丰度值表现为亏损,新元古界板溪群Sb、As、Ag平均含量和震旦系Sb、As、Ag、Au平均含量均高于扬子板块上地壳平均丰度值,而高丰度值主要发育在新元古界板溪群的凝灰岩以及震旦系洋水组的磷块岩中。黄铁矿电子探针的分析结果进一步说明,Sb、As和Au三种低温成矿元素主要存在于原生黄铁矿等矿物中。3)对低温成矿元素富集、赋存及其可能的改造和活化途径进行了综合的构造-沉积探讨。通过对洋水背斜的构造期次划分、研究区低温成矿元素背景特征以及区域地质演化史的梳理,可以认为洋水背斜的多期构造变形反映了华南地区在不同时期对Au、As以及Sb等低温成矿元素的活化和富集提供了有利的环境。以上成果对于深入了解黔中隆起的形成、演化,及其对区域内广泛发育的低温成矿作用的贡献,具有理论和实际意义。
[Abstract]:In order to explore the relationship between the tectonic attributes of the oceanic water anticline in the central Guizhou uplift and the material basis of large-scale low temperature metallogenesis in the region, this paper through the detailed field geological investigation, literature comprehensive arrangement. Tectonic analysis, geochemistry microanalysis and electron probe analysis have determined the structural style, deformation sequence, stage and origin of the oceanic water anticline. On this basis, the ore-forming elements SB of oceanic water anticline and low temperature have been determined. As,Ag. The anomalous relation of au abundance is discussed. In this paper, the main achievements are as follows: 1). The structural characteristics and formation process of the oceanic water anticline are dissected in detail. The structural analysis of 3 transverse sections and 1 longitudinal section of the ocean water anticline is carried out. Three tectonic deformations, namely D1 E-W longitudinal bend fold and D2 N-S longitudinal bend fold, as well as compression superposition reconstruction in the late D3 period are determined. The formation process of the oceanic anticline is from the Indosinian N-S fold D 2) to the Caledonian E-W fold D 1). Finally, the abnormal horizon of metallogenic elements at low temperature is determined and its occurrence state is preliminarily determined through the extrusion superposition reconstruction of D3 period in the late Yanshanian period. The geochemical analysis shows that the anomalous horizon of metallogenic elements at low temperature is determined. The contents of au in the Banxi Group except the Neoproterozoic are depleted in relation to the average crustal abundance of the upper Yangtze plate, the average content of SB _ (1) As-Ag in the Panxi Group of the Neoproterozoic and the Sinian system (Sinian). The average au content is higher than the average abundance value of the upper crust of Yangtze plate. The high abundance values are mainly developed in the tuff of the Panxi Group of the Neoproterozoic and the phosphorite of the Yangshui formation of the Sinian. Three low-temperature ore-forming elements, as and au, mainly exist in primary pyrite and other minerals. By dividing the tectonic stages of the oceanic water anticline, the background characteristics of low temperature metallogenic elements and the history of regional geological evolution in the study area are sorted out. It can be concluded that the multi-stage tectonic deformation of the oceanic anticline reflects the occurrence of au in different periods in South China. The activation and enrichment of low temperature metallogenic elements such as as and SB provide a favorable environment for further understanding the formation and evolution of the central Guizhou uplift and its contribution to the extensive low temperature mineralization in the region. It has theoretical and practical significance.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P612;P595

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