【作者】 周林立；

【导师】 胡光道；

【作者基本信息】 中国地质大学 ， 地球探测与信息技术， 2010， 博士

【摘要】 热液矿床几乎毫无例外地存在围岩蚀变。蚀变围岩的范围一般远远大于矿体,找到了蚀变围岩也往往意味着附近可能存在热液矿床,因此围岩蚀变可作为重要的找矿指标。蚀变矿物有其独特的光谱特性,这样可利用遥感快速的圈定蚀变带,再结合物化探资料进行分析,从而达到快速找矿的目的。云南个旧矿区是我国重要的锡、铜多金属矿产区,锡矿资源的开发与利用在个旧市的经济建设中占有举足轻重的地位。但历时几十年大规模的开采后,目前个旧锡矿许多矿山都面临着资源枯竭的问题,外围找矿、深部勘查、寻找新的矿点已成当务之急。横贯个旧南北的个旧断裂为将个旧锡矿分为东区、西区两个部分,东区是目前开采矿床的主要集中区,地质勘察程度高,个旧的五大矿山-马拉格、松树脚、高松、老厂卡房均分布于该区；而西区已知矿床分布较少,地质勘探开发程度低,因此是扩大矿区远景的找矿目标区。普雄矿区属个旧西区的一部分,行政设置隶属云南省建水县。距建水县城东南直线距离25千米(公路里程60千米),地理座标为东经102°58’,北纬23°。30’,面积约300平方千米。从从1954年起云南地质局下属勘察队已对该区进行了多次地质勘察工作,虽然找到了一些零星矿点,但一直没有重大发现。这说明传统的找矿方法在该区已很难有所作为,必须采用新的方法和理论,突破传统方法的局限,这样才能有所突破。本文以横向合作项目《普雄铅多金属成矿带深部隐伏矿预测》为依托；开展了遥感找矿信息提取的专题研究。主要研究了以下内容：1.研究了蚀变矿物提取的地质依据及蚀变矿物的波谱特征。论述了蚀变围岩与矿产的关系,介绍了几种主要蚀变围岩的特点及其对找矿的指导意义。从原子光谱产生机理、晶体场效应、电荷迁移等方面论述了岩矿光谱形成的物理机制,在此基础上探讨了典型蚀变矿物的光谱特征。探讨了干扰影响蚀变矿物的主要因素。2.区域成矿地质背景及其围岩蚀变特征。研究了普雄矿区所处区域的成矿地质背景,对研究区的基本情况做了简述,重点对区域地层建造、区域地质构造、区域岩浆作用及岩浆岩、区域矿产分布及特征进行了分析。最后,结合区域地质背景系统分析了研究区内围岩蚀变的类型及其分带特征,并对其与区域内矿产的关系做了探讨。3.区域遥感图像的获取及处理。主要对获取的ASTER原始数据进行了一系列的处理,包括几何校正、子区选择、辐射校正及大气校正,对研究区的ASTER遥感影像进行了统计分析,选取了最优波段进行彩色合成。4.遥感线环构造解译与提取。在运用多种方法对ASTER图像进行增强的基础上,建立了遥感图像的线性构造及环形构造的解译标志,对研究区的ASTER影像进行了线环构造的提取,并结合地质资料进行了分析。5.蚀变矿物波谱分析及遥感蚀变信息的提取。对研究区的蚀变岩石光谱进行了分析,特别分析了其对应ASTER各波段的反射或吸收特征。在去除蚀变信息提取中的干扰信息(植被、水系等)的基础上,依据蚀变矿物的波谱特征,优选了多种方法进行蚀变信息的提取,并对结果进行了比较分析。6.基于GIS平台的成矿预测。将遥感找矿作为一个独立的找矿指标，应用GIS平台将遥感构造、矿化蚀变、地质、物探、化探等成矿相关资料有机的结合起来，建立遥感成矿预测单元。经过以上研究工作得出以下结论和成果：1.本区断裂构造发育程度较高且与矿产关系密切。构造在构造形式上是以小褶皱及断裂构造为主的。构造与矿产关系密切非常,靠近龙岔河岩体的T2g中主要分布有铅锌、铁、锰、钼等矿点,这些矿点沿龙岔河岩体与个旧组灰岩接触带分布,受南岭纬向复杂构造体系所控制。受李海寨大断裂控制的次级断裂影响,靠近李海寨大断裂的九头山、畔山、大落水洞村的近东西向也集中分布有铅锌、铁、锰、钼等矿化点。2.利用遥感影像进行断裂构造的提取是有效可行的。构造在遥感影像上的标志非常明显,通过对原始遥感做适当的增强,再结合目视解译,可以快速的解译区域构造信息。这对后续地质工作的开展十分有利。3.本区围岩蚀变强烈且与矿产关系十分密切。普雄矿区的铅锌锡多金属矿床一般赋存在蚀变岩石之中,各类蚀变围岩环绕花岗岩侵入体,形成蚀变圈,超出这个范围很少发现矿床。这也意味着,一旦我们找到了相应的围岩蚀变,就有可能发现相应的矿床。4.在中等植被覆盖区利用ASTER数据也可提取到较好的蚀变异常。本研究区位于云南个旧区域,植被覆盖率较高,过去通常认为在这种情况下不适合进行蚀变信息的提取。通常在本区进行的蚀变信息提取工作表明,在中等植被区,通过对信息模型进行优化,也可以有不错的提取效果。最终提取的蚀变结果与已知大部分矿点相吻合,这也证明了在本区利用遥感蚀变信息提取进行找矿的思路是可行的。5.遥感蚀变异常可以作为一个与地质、地球化学、地球物理同等童要的找矿指标。过去,遥感信息仅仅作为地质找矿的一个辅助信息,未得到充分重视。事实上，充分发挥遥感区域覆盖范围光、调查不受自然条件限制等优点,可以大大加快找矿进程。本文的研究充分表明了这点。6.单独的遥感提取信息还需结合地质、物探、化探进行综合分析,分析后的结果才更为准确可行。本文的研究工作表明,遥感地质构造解译、矿化蚀变信息可以作为和地质、物探、化探同等重要的参数应用在矿产资源评价中,其对于矿产资源快速评价有十分重要的意义。7.在本文中结合了地质、物探、化探资料基于GIS平台利用证据权法进行了综合分析,并圈定了几个成矿远景区。①下纸厂-大黑山区域靶区：该区在深部及外围有较大的矿产资源潜力,是本区矿产资源潜力最大地区之一,应作为本区的工作重点。②落水洞-畔山一带：该区找到小型矿点、浅表矿点的可能性较大,可作为下一步工作的重点。③普家山靶区：有成矿地质条件,可进一步勘察。本次研究发现了以下问题有待后续研究解决：1.在遥感构造信息的提取前,虽然做了很多图像增强工作,但主要还是依据目视解译得到结果,这样有较强的主观性。需对遥感线环构造自动提取做进一步的研究。2.对研究区进行典型矿物波谱研究时,只对典型地物光谱做了采集,未充分考虑风化、表面颜色及岩石颗粒大小对矿物光谱的影响。在有条件的情况下，应尽量收集同种矿物的不同样本,对其做进一步的研究。3.由于ASTER波段的局限,限制了蚀变提取方法的选择。很多可以对岩矿进行准确识别的高光谱方法不能应用。在有条件的情况下,可采用高光谱数据进行进一步的研究。4.在整个遥感找矿工作流程确定的情况下,可考虑进行系统集成,开发基于GIS&RS的综合提取分析平台,使得工作流程自动化。更多还原

【Abstract】 Almost all the existence of hydrothermal deposits goes with rock alteration. In general the scope of altered rock is far greater than ore bodies. Found the altered rock also often means that there may be hydrothermal deposits. So wall-rock alteration can be used as an important exploration target. Alteration mineral has its own unique spectral characteristics, so use of remote sensing images can delineat altered area quickly. The result can be combined with geophysical and geochemical data analysis. In this way, we can achieve rapid prospecting purposes.Gejiu is an important tin, copper multi-metal mineral area in Yunnan province. Tin resource development and utilization occupies a pivotal position in the economic of the city. However, after a large-scale exploitation which lasted several decades, the current number of old tin mines are faced with resource depletion. The external prospecting and deep exploration to find a new point has become a top priority of mine. Gejiu fracture which across north-south of the city has divided the tin mines into Eastern, Western two parts. The Eastern is the exploitation of deposits in the main concentration area, a high degree of geological survey. The five old mine -Magela, Songshujiao, Gaoshong, Laochang, Kafang are scattered in the area; The Western part has few known deposits. And the geological exploration and development is low level at this area. Therefore it’s a target area for long-term expansion of mining prospecting.Puxiong area is in the western area of Gejiu. It’s belongs to Jianshui County of Yunnan Province. The Straight-line distance to the southeast city town is 2.5 km. It’s geographic coordinates is east trail 102°58’, latitude 23°30’. The acreage of the area is about 300 square kilometers. Since 1954 The Geological Survey team of the Yunnan USGS has conducted a number of geological survey works for the area. They found some sporadic occurrence from the work, but had found nothing of significance. This shows that the traditional method of prospecting in the area has been very difficult to make a difference; we must adopt new methods and theories, breaking the limitations of traditional methods.In this paper, we depend on the horizontal cooperation projects "Puxiong lead multi-metal ore belt deep concealed ore project" to carry out exploration of remote sensing information extraction. In the case, we major study of the following:1. Study of the alteration minerals extracted from the geological basis and alteration of the spectral characteristics of minerals. Discusses the relationship between the altered rock and mineral introduced several major characteristics of the surrounding rock alteration and its implications for prospecting guiding significance. Generation mechanism from the atomic spectra, crystal field effect, charge transfer, etc. discussed the physical mechanism of the formation of rock and mineral spectrum in this study based on the typical spectral characteristics of alteration minerals.2. Regional geological background and the characteristics of rock alteration.Study the geological background of the Puxiong ore mining area. Give a brief summarize of the basic situation of the study area. We do research on the construction of the regional stratum construction, regional geological structure, the regional magma construction and magma rocks, regional distribution and the characteristics of mineral. Finally, we analyze the type of wall-rock alteration and its sub-zone characteristics, and their relationship with the region of the study area basic on the study of mineral, the combination of regional geological.3. Regional remote sensing image acquisition and processing.Mainly to obtain a series of ASTER raw data processing, including geometric correction, sub-area selection, radiometric and atmospheric correction. We do a statistical analysis of remote sensing images of the study area; select the optimal band for color composite.4. The interpretation of remote sensing wire loop construction and extraction.A variety of methods has been used on the ASTER image to enhance remote sensing images. Base on it, we construct the interpretation of signs for the linear structure and circular structure. We extract the ine and ring structures of the study area from the ASTER images. Finally the result combined with geological data was analysis.5. The alteration minerals alteration spectral analysis and remote sensing information extraction.The spectra of the altered rocks of the study area were analyzed. In particular, we analyses the reflectance or absorption characteristics of the spectra in each band of the ASTER image. Based on the removing of the interference information (vegetation, water, etc.)to the Alteration Information Extraction, we adopt a variety of methods for alteration of information extraction based on the study of the spectral characteristics of alteration minerals.6. Metallogenic prediction based on GIS PlatformIn the end, geological, geophysical and geochemical favorable ore-forming information of the study area have been integrated. Based on the GIS platform, we do a comprehensive analysis of multivariate information.The above study got the following conclusions and results:1.Faults in this area have a high degree of development and have close ties with the mineral. Faults in constructing orient the form of small folds and faults. Faults and mining are very close. Close to the Long Chahe rock T2g the main distribution are zinc, iron, manganese, molybdenum and other mineral point, these mine sites along the Long Chahe limestone rock contact zone with the old distribution, subject to Nanling latitudinal structural system under the control of the complex. By Lihaizai secondary faults and large faults control the impact of large faults. Near the Lihaizai Jiutoushan, Banshan, near the village of Da luoShuidong have also focused on the distribution of lead, zinc, iron, manganese, molybdenum and other mineralization. 2. Using remote sensing images for faults extraction is feasible and effective. Faults in remote sensing images on the signs are very clear, through the original remote to make the appropriate enhancements, combined with visual interpretation; you can quickly interpret regional tectonic information. Caring out the follow-up geological work are very favorable by this.3. Rock alteration in this area is strong and has very close relationship with the mineral. Puxiong tin-lead-zinc mine metal deposits in the general existence of altered rocks assigned among the various types of altered rocks surrounding the granite intrusion, the formation of altered circle, rarely found in deposits beyond this range. It also means that, in this area, once we find the corresponding wall-rock alteration, is likely to find the corresponding deposit.4. In the middle vegetation coverage area using ASTER data can also extract good alteration anomalies. This study area is located in Gejiu area,Yunnan province. The vegetation coverage is high, it is normally considered in this case is not suitable for alteration of information extraction. Usually in the area of the alteration information extraction work shows that in secondary vegetation areas, through the information model to optimize the extraction can also have a good effect. Altered the results of the final extracted most of the mining points and the known coincide, which proves that alteration in this area using remote sensing information extraction to the idea of exploration is feasible.5. Remote sensing can be used as an alteration anomalies and geological, geochemical and geophysical prospecting indicators are equally important. In the past, remote sensing information only as a secondary information of geological prospecting not given adequate attention. In fact, give full play to regional coverage of remote sensing light, the investigation from natural conditions, etc., can greatly speed up the exploration process. This study fully demonstrates this point.6. Individual extract information of remote sensing needs to combination with geological, geophysical and geochemical exploration for comprehensive analysis. The results of the analysis are more accurately possible. This research demonstrated that remote sensing interpretation of geological structure, mineralization and alteration of information can be used as geological, geophysical and geochemical parameters are equally important applications in the evaluation of mineral resources, its has very important significance for the rapid evaluation of. mineral resources.In this paper a combination of geological, geophysical and geochemical information on the use of evidence-based GIS platform to the right of France conducted a comprehensive analysis and delineation of a number of ore prospecting area. There are:①Xiazhichang-Large Montenegro regional target area: the area in the deep and external have a greater potential for mineral resources is the greatest potential for mineral resources in this area one of the areas should serve as a focus of the work in this area.②Luoshuidong-Panshan area: the area to find small-scale mining points, superficial likely mine sites can be used as the next focus of work.③PuJiashan target area: There are ore-forming geological conditions, could be further investigation.Although this study had some success, but there is much to be desired. Studies have identified the urgent need for follow-up study following address: 1. The extraction of structural information in remote sensing, even though it made a lot of image enhancement, but mainly to get results based on visual interpretation, so that there is a strong subjectivity. The further study for automatic extraction of remote sensing wire ring structure is needed.2. Typical of the study area of mineral spectrosccpy study, only the typical features in spectra collected do not take full account of weathering, su face color and rock particle size on the impact of mineral spectrum. In the case of a conditional should try to collect different kinds of mineral samples for their further study.3. ASTER band due to the limitations, limiting the choice of extraction method altered. Many rock and mineral can be accurately identify the high-spectral methods can not be applied. In the conditional case, hyper spectral data can be used for further study.4. Remote sensing exploration in the whole workflow defined circumstances, be considered for system integration, develop a comprehensive GIS & RS based on the extraction analysis platform, enabling workflow automation.更多还原