相山邹家山地区钻孔岩心蚀变的高光谱特征及地质意义

发布时间：2018-04-30 12:23

本文选题：相山邹家山地区 + 高光谱　；参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：高光谱遥感技术可以快速地识别热液蚀变矿物,进而划分蚀变分带,而且可以根据某些特定蚀变矿物的光谱特征变化规律圈定可能的热液/矿化中心。相山铀矿田的蚀变特征一直是本地区的研究热点,本文基于高光谱遥感技术,利用地面高光谱仪器对相山邹家山地区ZK1、ZK2、ZKR1三个钻孔岩心进行蚀变矿物扫描和研究,研究结果表明:(1)钻孔岩心中热液蚀变矿物主要有富铝水云母、贫铝水云母、绿泥石、蒙脱石、碳酸盐、地开石、高岭石。高岭石与地开石主要吸收峰都在2210nm附近,有次级吸收峰;贫铝水云母的Al-OH特征吸收峰在2223nm附近,富铝水云母在2210nm附近;绿泥石的特征吸收峰在2367nm与2265nm处,表现为为铁绿泥石的特征,反映了热液的还原环境;碳酸盐矿物在2348nm附近。(2)蚀变矿物的分布垂向上表现出“上酸下碱”、“酸碱叠加”的特征;富铝水云母在钻孔上部含量多而下部含量减少,表现出酸性蚀变矿物的分布特征;贫铝水云母在钻孔上部含量少,而在下部含量明显增多;碳酸盐矿物多呈脉状广泛分布。矿化段有贫/富铝水云母、绿泥石、方解石与赤铁矿叠加的组合特征。(3)对比三个钻孔的蚀变情况及地质资料发现,构造破碎带或裂缝部位是蚀变发育强烈的部位,而构造与岩性较为均一的ZKR1钻孔的蚀变变化较小。由ZK2钻孔可以看出,与矿化密切相关的有水云母化、绿泥石化、赤铁矿化及密集的构造裂隙。总体的蚀变特征可能是在深部碱性热液长期活动过程中逐渐转变为中性、酸性叠加并改造了前期碱性蚀变的结果。(4)针对伊利石(水云母)的光谱进行沙漏提取,并将三个钻孔进行对比,发现伊利石SWIR-IC结晶度随深度增加表现出良好的递增趋势,证明热液活动中心在深部。Al-OH特征吸收峰位置随深度增加向长波长方向移动。1900nm处特征吸收峰无明显规律。推测该地区影响水云母2200nm吸收峰位置的主导因素是不同性质流体的离子浓度。总体来看,高光谱成像仪在蚀变信息提取及岩心编录的应用上有良好的效果,能获取丰富的蚀变信息,并反映出更多的地质信息。
[Abstract]:Hyperspectral remote sensing technology can quickly identify hydrothermal altered minerals and then divide them into altered zones and delineate possible hydrothermal / mineralized centers according to the spectral characteristics of some particular altered minerals. The alteration characteristics of Xiangshan uranium ore field have been the focus of research in this area. Based on hyperspectral remote sensing technology, this paper uses the surface hyperspectral instrument to scan and study the altered minerals in the cores of ZK1 and ZK2 and ZKR1 boreholes in Zoujiashan area, Xiangshan. The results show that the hydrothermal alteration minerals in the core of the borehole are mainly aluminum-rich hydromica, aluminum-poor hydromica, chlorite, montmorillonite, carbonate, dicathite and kaolinite. The main absorption peaks of kaolinite and dickite are near 2210nm, there are secondary absorption peaks, the Al-OH characteristic absorption peak of aluminum-poor mica is near 2223nm, and the characteristic absorption peak of chlorite is near 2210nm, and the characteristic absorption peak of chlorite is at 2367nm and 2265nm. It is characterized by the characteristics of ferric chlorite, which reflects the reduction environment of hydrothermal solution, and the distribution of carbonate minerals in the vicinity of 2348nm. The distribution of altered minerals shows the characteristics of "upper acid and lower alkali" and "acid-base superposition" vertically. Aluminum-rich hydromica has more content in the upper part of the borehole and less in the lower part, which shows the distribution characteristics of acid altered minerals; the content of the low-alumina hydromica in the upper part of the borehole is less, but the content in the lower part is obviously increased; the carbonate minerals are widely distributed in vein shape. The alteration situation and geological data of the three boreholes in comparison with the combination characteristics of poor / aluminum-rich hydromica, chlorite, calcite and hematite superimposed on hematite show that the structural fracture zone or fracture area is the place where the alteration is strongly developed. However, the alteration of ZKR1 boreholes, where the structure and lithology are more homogeneous, is relatively small. It can be seen from the ZK2 borehole that there are hydromica, green mud fossilization, hematite mineralization and dense structural fissures closely related to mineralization. The overall alteration characteristics may be that the alkaline hydrothermal solution in the deep layer gradually changed to neutral during the long period of activity. The acid superposition and modified the result of the earlier alkaline alteration. (4) the hourglass extraction of the spectrum of Illite (hydromica) is carried out. By comparing the three boreholes, it is found that the crystallinity of Illite SWIR-IC shows a good increasing trend with the increase of depth. It is proved that the characteristic absorption peak of hydrothermal active center moves to the direction of long wavelength at .1900 nm with the increase of depth. It is inferred that the dominant factor affecting the location of 2200nm absorption peak of hydromica in this area is the ionic concentration of different fluids. In general, the hyperspectral imager has a good effect on the extraction of alteration information and the application of core cataloguing, which can obtain abundant alteration information and reflect more geological information.
【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】：P627

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