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1.
Lineament extraction and analysis is one of the routine work in mapping medium and large areas using remote sensing data, most of which are satellite images. Landsat Enhanced Thematic Mapper （ETM） of 945×1 232 pixels subscene acquired on 21 March 2000 covering the northwestern part of Yunnan Province has been digitally processed using ER Mapper software. This article aims to produce lineament density map that predicts favorable zones for hydrothermal mineral occurrences and quantify spatial associations between the known hydrothermal mineral deposits. In the process of lineament extraction a number of image processing techniques were applied. The extracted lineaments were imported into MapGIS software and a suitable grid of 100 m×100 m was chosen. The Kriging method was used to create the lineament density map of the area. The results show that remote sensing data could be useful to extract the lineaments in the area. These lineaments are closely correlated with the faults obtained through other geological investigation methods. On comparing with field data the lineament-density map identifies two important high prospective zones, where large-scale deposits are already existing. In addition the map highlights unrecognized target areas that require follow up investigation. 相似文献
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http://www.sciencedirect.com/science/article/pii/S1674987111001137 总被引：12，自引：1，他引：11
Integration of remote sensing data and the geographical information system(GIS) for the exploration of groundwater resources has become a breakthrough in the field of groundwater research, which assists in assessing,monitoring,and conserving groundwater resources.In the present paper, various groundwater potential zones for the assessment of groundwater availability in Theni district have been delineated using remote sensing and GIS techniques.Survey of India toposheets and IRS-1C satellite imageries are used to prepare various thematic layers viz.lithology,slope,land-use,lineament, drainage,soil,and rainfall were transformed to raster data using feature to raster converter tool in ArcGIS.The raster maps of these factors are allocated a fixed score and weight computed from multi influencing factor(MIF) technique.Moreover,each weighted thematic layer is statistically computed to get the groundwater potential zones.The groundwater potential zones thus obtained were divided into four categories,viz.,very poor,poor,good,and very good zones.The result depicts the groundwater potential zones in the study area and found to be helpful in better planning and management of groundwater resources. 相似文献
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Farid Moore Fatemeh Rastmanesh 《中国地球化学学报》2006,25(B08):226-226
The Takab area in NW of Iran is an important gold mineralized region with a long history of gold mining. In this study ASTER data is used to evaluate environmental effects of gold mining. The results show that mining activities have resulted in release of potentially toxic metals （PTMs） in the area. Principal component analysis （PCA） of ASTER data is used to map sources of PTMs and their secondary hosts （iron oxides） through alteration mapping. The results show that selective PCA is a robust yet time consuming technique for alteration mapping. A color composite is created for finding common hydrothermally altered rocks. The created color composite successfully mapped the known deposits and anomalous areas identified by geological survey of Iran. Because of the low spatial resolution of ASTER sensor, the iron oxide mapping is restricted to the wider portions of the streams. Spectral analyses confirm the presence of hematite and goethite in stream sediments. This is in accordance with measured pH values. 相似文献
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GONG Yiming Faculty of Earth Science China University of Geosciences Wuhan LI Baohua Laboratory of Marine Geology Tongji University Shanghai WU Yi Guangxi Institute of Geology Nanning 《《地质学报》英文版》2001,75(4):354-363
Four hierarchical cyclothems, superbundlesets, bundlesets, bundles and laminae, have been identified from the Devonian Frasnian-Famennian carbonate strata in Guangxi, South China. Their hierarchical structures, ratio relationships and sequence in conodont zones are continuous and stable and can be traced across different facies zones and sedimentary basins. Our data show that hierarchically organized superbundlesets, bundlesets, bundles and laminae correspond to the long eccentricity, eccentricity, obliquity or precession and sub-Milankovitch cycles respectively. Their periods were 400,000, 100,000, 33,333, 16,667 and 8,000-17,000 a, respectively. The ratios of long eccentricity to eccentricity, eccentricity to obliquity, and eccentricity to precession in the Devonian are 1:4, 1:3 and 1:6 respectively. Using these hierarchical Milankovitch cyclothems, chronostratigraphical division and correlation can be realized at a resolution of 100 ka or 10 ka at the Frasnian-Famennian transition. The time intervals 相似文献
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Geological Fluid Mapping in the Tongling Area： Implications for the Paleozoic Submarine Hydrothermal System in the Middle-Lower Yangtze Metallogenic Belt, East China 总被引：1，自引：0，他引：1 
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下载免费PDF全文 HOU Zengqian YANG Zhusen MENG Yifeng ZENG Pusheng LI Hongyang XU Wenyi 《《地质学报》英文版》2007,81(5):833-860
The Tongling area is one of the 7 ore-cluster areas in the Middle-Lower Yangtze metallogenic belt,East China,and has tectonically undergone a long-term geologic history from the late Paleozoic continental rifting,through the Middle Triassic continent-continent collision to the Jurassic-Cretaceous intracontinental tectono-magmatic activation.The Carboniferous sedimentary-exhalative processes in the area produced widespread massive sulfides with ages of 303-321 Ma,which partly formed massive pyrite-Cu deposits,but mostly provided significant sulfur and metals to the skarn Cu mineralization associated with the Yanshanian felsic intrusions. To understand the Carboniferous submarine hydrothermal system,an area of about 1046 km~2 was chosen to carry out the geological fluid mapping.Associated with massive sulfide formation,footwall sequences 948 m to 1146m thick,composed of the Lower Silurian-Upper Devonian sandstone,siltstone and thin-layered shale,were widely altered.This hydrothermal alteration is interpreted to reflect large- scale hydrothermal fluid flow associated with the late Paleozoic crustal rifting and subsidence.Three hydrothermal alteration types,i.e.,deep-level semiconformable silicification(S_1),fracture-controlled quartz-sericite-pyrite alteration(S_(2-3)),and upper-level sub-discordant quartz-sericite-chlorite alteration(D_3),were developed to form distinct zones in the mapped area.About 50-m thick semiconformable silicification zones are located at～1-km depth below massive sulfides and developed between an impermeable shale caprock(S_1)and the underlying Ordovician unaltered limestone. Comparisons with modern geothermal systems suggest that the alteration zones record a sub-seafloor aquifer with the most productive hydrothermal fluid flow.Fracture-controlled quartz-sericite-pyrite alteration formed transgressive zones,which downward crosscut the semiconformable alteration zones, and upwards grade into sub-discordant alteration zones that enveloped no economic stringer- stockwork zones beneath massive sulfides.This transgressive zone likely marks an upflow path of high- flux fluids from the hydrothermal aquifer.Lateral zonation of the sub-discordant alteration zones and their relationship to overlying massive sulfide lenses suggest lateral flows and diffusive discharging of the hydrothermal fluids in a permeable sandstone sequence.Three large-sized,14 middle-small massive sulfide deposits,and 40 massive sulfide sites have been mapped in detail.They show regional strata- bound characters and two major styles,i.e.,the layered sheet plus strata-bound stringer-style and the mound-style.Associated exhalite and chemical sedimentary rock suites include(1)anhydrite-barite,(2) jasper-chert,(3)Mg-rich mudstone-pyrite shale,(4)barite lens,(5)siderite-Fe-bearing dolomite,and (6)Mn-rich shale-mudstone,which usually comprise three sulfide-exhalite cyclic units in the area. The spatial distribution of these alteration zones(minerals)and associated massive sulfides and exhalites,and regional variation inδ~(34)S of hydrothermal pyrite and inδ~(18)O-δ~(34)C of hanging wall carbonates,suggest three WNW-extending domains of fluid flow,controlled by the basement faults and syn-depositional faults.Each fluid domain appears to have at least two upflow zones,with estimated even spacing of about 5-8 km in the mapped area.The repeated appearance of sulfide-sulfate or sulfide-carbonate rhythmic units in the area suggests episodically venting of fluids through the upflow conduits by breaking the overlying seals of the hydrothermal aquifer. 相似文献
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BassamFAIBassam 《中国地质大学学报(英文版)》2003,14(3):283-292
Gengma region, Sanjiang district is known to have some large-scale gold deposits. GIS predictive model for hydroghermal gold potential was carried out in this region using weights of evidence modeling technique. Datasets used include large-scale hydroghermal gold deposit records, geological, geophysical and remote sensing imagery. Based on the geological and mineral characteristics of areas with known gold occurrences in Sanjiang, several geological features were thought to be indicative of areas with potential for the occurrence of hydroghtermal gold deposits. Indicative features were extracted from geoexploration datasets for use as input in the predictive model. The features include host rock lithology, geologic structures, wallrock alteration and associated (volcanic-plutonic) igneous rocks. To determine which of the indicative geological features are important spatial predictors of area with potential for gold deposits, spatial analysis was done through the modeling method. The input maps were buffered and the optimum distance of spatial association for each geological feature was determined by calculating the contrast and studentized contrast. Five feature maps were converted to binary predictor patterns and used as evidential layers for predictive modeling. The binary patterns were integrated in two combinations, each of which consists of four patterns in order to avoid over prediction due to the effect of duplicate features in the two structural evidences. The two produced potential maps define almost similar favorable zones. Areas of intersections between these zones in the two potential maps placed the highest predictive favorable zones in the region. 相似文献
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Proceeding from gaining a knowledge of the structural settings in this area, the authors applied remotesensing techniques and selected multi-temporal image processing to extract information of buried structures inthe Beijing plain area. Good results have been achieved. Through an integrated analysis of remote-sensing, geo-logical, seismic and aeromagnetic data, it is pointed out that there exist two sets of buried fractures of differingtrends and orders-the northeast set and the northwest set. forming a rhombic framework in the images. Thetwo sets of fractures have still been active since the Quaternary. which is of practical signifcance for geologicalstudy, earthquake prevention and planning of urban construction in the area. The results demonstrate that theselection of multi-temporal processing of remote sensing images and the integrated analytic method are impor-tant in the study of buried structures. 相似文献
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Integrated gravitational, electrical-magnetic surveys and data processing carried out in the Sanshandao–Jiaojia area, Eastern Shandong Province, northeast China, aim to illuminate the geological characteristics of this shallow-covered area and delineate deep-seated gold prospecting targets. In this region, altogether 12 faults exert critical control on distribution of three types of Early Precambrian metamorphic rock series, i.e. those in the metamorphic rock area, in the granitic rock area underlying the metamorphic rock, and in the remnant metamorphic rock area in granites, respectively. Additionally, the faults have major effects on distribution of four Mesozoic Linglong rock bodies of granite, i.e. the Cangshang, Liangguo, Zhuqiao-Miaojia and Jincheng granites. The Sanshandao and Jiaojia Faults are two well-known regional ore-controlling faults; they have opposite dip direction, and intersect at a depth of 4500 m. Fracture alteration zones have striking geophysical differences relative to the surrounding county rocks. The two faults extend down along dip direction in a gentle wave form, and appear at some steps with different dips. These steps comprise favorable gold prospecting areas, consistent with a step metallogenic model. Six deep-seated gold-prospecting targets are delineated, i.e. Jincheng-Qianchenjia, Xiaoxizhuang-Zhaoxian, Xiyou-Wujiazhuangzi, Xiangyangling-Xinlicun, Panjiawuzi and Miaojia-Pinglidian. 相似文献
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Limin REN Bing QIN Wenchun TANG Zhendong MA Yikeng HU 《中国地球化学学报》2006,25(B08):10-10
Mercury is a pollutant of concern due to its toxic and bioaccumulative properties. Studies on the distribution and hazard of mercury in the environment are mainly focused on its forms, toxicity and the environment standard, and progresses and results have been achieved. But these studies in the past were concentrated on the scales of laboratory or smaller districts merely, such as a small unit of mineral area, vegetable base, paddy field, lake, etc. Multi-target regional geochemical survey carried out by China Geological Survey from the 1990s to now is a fundamental and commonweal geological survey, large-scale and systematical inquisition and research were conducted in 19 provinces （or municipalities directly under the Central Government） in the eastern overlay region of China, and the purpose is to provide the basic geochemical data for national economic construction, adjustment of industrial and agricultural structures and sustainable social development. Geochemical studies aim at investigating soils in these regions and 52 elements have been tested, producing a great amount of data at the same time. Methods： based on the data from 3061 samples of surface soil and 832 samples of deep soil from the project of multi-purpose geochemical survey in the Chengdu Basin, Sichuan, China, this paper describes the correlation relationship between Hg and other 48 elements and their spatial distribution in surface and deep soils of these areas by applying the method of linear regression and factor analysis. 相似文献
10.
Zhaozhou ZHU Congqiang LIU Zhongliang WANG Bo GAO Zhihua ZHOU Jun LI 《中国地球化学学报》2006,25(B08):150-150
The rare-earth elements （REEs） are a series of elements including lanthanides with atomic numbers from 57 to 71, as well as Y with an atomic number of 39. The REEs are commonly used as geochemical tracers in the study of many geologic processes because of their unique and chemically coherent behavior. The main purpose of this research is to understand the effect of water-particle interaction on trace metal transport, the distribution and chemical species of the REEs in water through case studies on geochemical behavior of the REEs in the Chaohu and Longgan lakes, eastern China. Concentrations of the dissolved REEs were detected by ICP-MS （Inductively Coupled Plasma-Mass Spectrometry）. Before ICP-MS measurement, REEs were concentrated from water samples by using solvent extraction and back extraction with a mixture 65% HDEHP （2-etheylhexyl hydrogen phosphate） and 35% H2MEHP （2-ehtylhexyl dihydrogen phosphate）. The results showed that the average concentrations of dissolved REEs in summer are higher than in winter for Chaohu Lake： they were 162.6 ng/kg and 86.5 ng/kg, respectively. On the country, the REE contents of winter samples were higher than those of summer water samples for Longganhu Lake： they were 111.1 ng/kg and 44.0 ng/kg, respectively. The contents of suspended particulate matter and pH are the two important factors controlling the concentrations of dissolved REE in the lakes. The contents of the REEs decrease with increasing pH in the Longgan and Chaohu lakes. The suspended particulate matter shows different sorption/desorption toward the dissolved REEs in the two water bodies. Most lake water samples have a fiat NASC-normalized REE pattern, and the others have heavy REE-enrichment patterns relative to NASC, which may imply that the dissolved REEs were mainly present in the form of fine colloids in the Chaohu and Longgan lakes. 相似文献
11.
Uday Kumar Ghosh K. K. Naik M. P. Kesari 《Journal of the Geological Society of India》2016,88(4):464-470
The extraction of spectral signature through remote sensing data in geological studies is very limited in Indian terrain. The present research is an attempt to delineate alteration and associated minerals using high resolution multispectral advanced space borne thermal emission and reflection (ASTER) data in Sakoli volcano-sedimentary sequence. The alteration zones are generally associated with certain types of mineral and mineral aggregates and are localized in the ground that can be mapped remotely using spectral mapping techniques. The band ratio and selective PCT were applied on calibrated ASTER image to extract spectral signature of index mineral. The results showed that high abundance of these minerals within pixels is corresponding to the alteration zones. The field observation, petrography and XRD analysis of the alteration zones confirmed the presence of dominant mineral phases that were identified remotely. 相似文献
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Western Altun in Xinjiang is an important area, where lithium(Li)-bearing pegmatites have been found in recent years. However, the complex terrain and harsh environment of western Altun exacerbates in prospecting for Li-bearing pegmatites. Therefore, remote-sensing techniques can be an effective means for prospecting Li-bearing pegmatites. In this study, the fault information and lithologyical information in the region were obtained using the median-resolution remotesensing image Landsat-8, the ... 相似文献
15.
在利用遥感数据和地理信息系统(GIS)技术的矿产资源勘查与评价中,矿化蚀变信息提取和构造信息提取起着至关重要的作用。以缅甸铜金矿为例,利用ETM+遥感图像,采用比值法、阈值分割和主成分分析(PCA)提取羟基蚀变信息;利用数字高程模型和遥感数据提取与铜金矿化有关的线环构造,结合地质资料和上述信息,利用证据权和分形方法进行整合,确定该研究区的成矿远景区。结果发现,已知铜金矿均分布于成矿靶区中,综合信息可为下一步的矿产资源勘探工作提供决策依据。 相似文献
16.
高光谱数据处理及其在广西苗儿山地区的地质应用研究 总被引：8，自引：0，他引：8
本文以广西苗儿山地区机载成像细分红外高光谱数据为例,探讨了高光谱数据的特点及其处理方法。编制了一系列进行数据预处理的软件,进行了条带去除、波段间配准、航向压缩、镜向变换、辐射校正、正切校正、相对反射率转换等预处理,获得了高质量图像。在ＥＮＶＩ软件基础上建立了研究区野外实测光谱曲线库及分类子库,并对各子库进行了系统研究。同时,提出了正确的配准方案,对图像进行了精校正和镶嵌,取得了满意的镶嵌图像;在纯净像元提取、混合像元分解、匹配滤波、光谱特征拟合等方面进行了探索。最后,探讨了高光谱数据的地质应用潜力,尤其在硅化带识别方面取得了成功的效果,发现了一系列新的含铀硅化断裂带;预测了３片成矿有利地段,经验证,在其中两片地区找到了明显的铀偏高和矿化显示。 相似文献
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Nirmala Jain Ramdayal Singh Priyom Roy Tapas R. Martha K. Vinod Kumar Prakash Chauhan 《Arabian Journal of Geosciences》2018,11(16):455
We explored the utilization of Landsat-8 Operational Land Imager (OLI) data for mapping of hydrothermal alteration zones. The region in and around the cities of Dungarpur and Udaipur of Rajasthan state in India was selected for this study. The rock types of Dungarpur and Udaipur are serpentinites, talc-carbonate, talc-schist, and quartzite of the Aravalli Supergroup. Hydrothermally altered zones and resultant hydrous minerals play an important role in the genesis of these rocks. We aimed to identify possible locations of hydrothermally altered zones in regional context around Dungarpur and Udaipur using Landsat-8 OLI data. False-color composite maps and band ratios were prepared from Landsat-8 bands. Band ratios such as band 6/band 7 (short-wave infrared 1 (SWIR1)/short wave infrared 2 (SWIR2)), band 4/band 3 (red/green), and band 5/band 6 (near infrared (NIR)/SWIR1) and visual interpretation techniques were used to identify the hydrothermally altered zones. Spectroscopic analyses of field rock samples were done to validate the hydrothermal alteration zones delineated from the analysis of Landsat-8 data. We present the combined results of Landsat-8 and field spectroradiometer analysis which brings out the hydrothermal alteration zones associated with hydrous minerals (antigorite, lizardite, montmorillonite, vermiculite, talc, and saponite). The study demonstrates the utility Landsat-8 OLI (with field spectroradiometer data) in the mapping of hydrothermally altered zones as a key in understanding geological processes. 相似文献
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为深入研究和探讨高分五号(GF-5)航天高光谱遥感技术在铀矿地质找矿中的应用效果和潜力,基于龙首山成矿带航天高光谱数据,开展高光谱数据处理和蚀变信息提取工作,创新实现了GF-5高光谱波段修复,通过构建标准光谱库和诊断光谱,运用MNF算法、PPI算法,结合SAM光谱角填图技术,完成蚀变矿物端元提取和光谱匹配,实现研究区钠长石、方解石、石英、绿泥石、赤铁矿和高岭土蚀变矿物的提取,综合区域铀矿成矿地质背景,通过开展地面波谱测量和野外调查,在验证蚀变准确度的基础上,剖析航天高光谱蚀变信息和成矿规律,构建了区域找矿定位模型,圈定找矿预测区3处,取得了较好的找矿效果,为国产GF-5高光谱遥感在地质找矿中的应用提供了参考。 相似文献
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A Comparative Study of Landsat‐7 and Landsat‐8 Data Using Image Processing Methods for Hydrothermal Alteration Mapping 下载免费PDF全文
下载免费PDF全文 Feizollah Masoumi Taymour Eslamkish Mehdi Honarmand Ali Akbar Abkar 《Resource Geology》2017,67(1):72-88
Comparing spaceborne satellite images of Landsat‐8 Operational Land Imager (OLI) and Landsat‐7 Enhanced Thematic Mapper plus (ETM+) was undertaken to investigate the relative accuracy of mapping hydrothermal alteration minerals. The study investigated the northern part of Rabor, which contains copper mineralization occurrences, and is located in the Kerman Cenozoic magmatic assemblage (KCMA), Iran. Image processing methods of band ratio, principal component analysis (PCA), and spectral angle mapper (SAM) were used to map the distribution of hydrothermally altered rocks associated with the porphyry copper mineralization. The band ratio combination of both sensors for mapping altered areas showed similar outcomes. PCA exposed variations in the spatial distribution of hydroxyl‐bearing minerals. The representation of hydrothermal areas using OLI data was more satisfactory than when using ETM+ data. SAM analysis found similar results for mapping hydroxyl‐bearing zones. Verification of the results came through ground investigation and laboratory studies. Rock samples (n = 56) were collected to validate results using thin sections, X‐ray diffraction (XRD) and spectral analyses. Field observations and laboratory analysis revealed that phyllic and propylitic alterations dominate the alteration zones in the study area. Argillic and iron oxides/hydroxides alterations were observed to a lesser degree. The results indicate that alteration maps prepared by OLI data using PCA for visual interpretation are more suitable than those of ETM+ due to a higher radiometric resolution and lower interference between vegetation and altered areas. As the spectral bandwidth of ETM+ band 7 covers absorption feature of propylitic alteration, better mapping of propylitic alterations is achieved using ETM+ data. 相似文献
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四川宁南铅锌矿集区是中国重要的铅锌矿成矿区之一，区内铅锌矿床广泛分布，其围岩蚀变主要为白云岩化、方解石化、黏土矿化、硅化、黄铁矿化及赤铁矿化，是重要的找矿标志，同时也为遥感提取铁染、羟基、碳酸根离子蚀变信息提供了重要的理论依据。由于遥感卫星传感器类型的不同，同一研究区内不同种类影像所得到的数据会有所差异，且采用不同的提取方法所得到的蚀变信息结果也会有所不同，因此，对同一区域进行单一影像或单一提取方法的研究往往存在偶然性与不充分性。据此，文章基于对研究区内Landsat8与GF-5两种影像数据的详细解读，采用3种有效方法进行蚀变信息提取。①波段比值法，对影像数据采用波段比值计算，并对波段比值进行密度分割，从中突出铁染，羟基、碳酸根离子蚀变信息；②主成分分析法和主分量密度分割法对铁染蚀变信息，羟基、碳酸根离子蚀变信息进行提取并作分级处理，结合GF-2高空间分辨率影像以及依据同谱异物、同物异谱、混合像元等原理剔除伪异常，以得到有效的蚀变信息；③光谱角匹配法，通过提取GF-5高光谱影像数据的纯净端员，结合光谱角匹配技术提取有效的蚀变信息矿物。对2种影像数据分别用3种提取方法所得到的蚀变信息结果进行对比，讨论其差异性，并通过叠合已知矿产地信息的方法筛选出效果较好的蚀变信息，将选取出的结果进行综合比对，最终在宁南矿集区圈定出预测靶区，经过室内化探数据验证及野外实地工作验证，证实其真实性，同时也为该地区下一步工作提供真实可靠的资料。 相似文献