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1.
This paper discusses the application of the model in predicting for hydrothermal Cu, Ag, Au and Pb-Zn occurrences in northwestern Yunnan. Geochemical, lineament and lithology data were the selected recognition criteria. The mentioned criteria varied against 75 known hydrothermal occurrences; the geochemical data had a weight of （W^＋= 1. 209 7, W^- =-0. 748 1） being the maximum among the three and the rest lineament and lithology have （W^＋= 0.7424, W^-= -0.449 6）, （W^＋= 0.378 7,W^-=-0.6243） respectively. The application was successful since the predicted results covers about 70% of the known deposits and predicted unknown areas.  相似文献   

2.
Abstract

Photogeological techniques were used to analyze Landsat‐TM images of the Paraiba State, which resulted in the identification of the following structures: lineaments of regional extent, short en echelon lineaments, intricate ramification of the wrench system, and infrastructures among major lineaments and circular or ring structures. This lineament map was correlated to existing geological maps, to areas of known hydrothermal mineralization (Cu, Au, Mo, Ni, W and Ti), and the lineament map was verified in the field reconnaissance. Due to lack of systematic studies of the geology and natural resources of the region the mineral exploration is still in rudimentary stages. The objective of this research is to emphasize the detection and analysis of lineaments, their patterns, and geometry and their relations with the occurrence of mineral resources and its exploration in areas as yet explored. A large number of mineral‐bearing pegmatites of the region are controlled by major lineaments and associated minor lineaments. It is believed that the structures of interest in search for mineral deposits are warping part of the minor shear zones, the intersections of short and regional lineaments, and the circular features.  相似文献   

3.
Kimberlite clan of rocks (KCR) comprising of mantle derived ultrabasic rocks such as Kimberlite and related Lamproites and Lamprophyres,are the primary source of diamond. Locating the KCR is first step in the diamond exploration, which is highly challenging in the field due to (i) very small spatial extent of KCR pipes (ii) high susceptibility of KCR to weathering and alteration on exposure to atmosphere, owing to their ultrabasic composition. Predictive statistical models using the geospatial data are often used to minimize the search and the present work attempts to apply the Frequency Ratio (FR) based predictive model in GIS to prepare KCR potential zone maps based on the relationship between the already explored KCR locations and the factors that favour their emplacement. Wajrakarur Kimberlite Field (WKF) in the Dharawar Craton of India, with more than 30 explored kimberlite pipes is selected as the study area. Geospatial technology has been used to generate thematic maps such as known KCR pipe locations, lineament density, lineament buffer zone, lineament intersection buffer zone, drainage anomaly buffer zone, geomorphology, and classified image showing distribution of mineral such as clay, iron oxide and calcrete, which are surface expression of KCR emplacement from various sources. Landsat 8 OLI satellite data, ASTER DEM were used in preparing the geomorphology, lineament map, and band ratio based mineral classified map. The thematic maps were converted to raster grid of 10 sq. m. FR values for each unit in each thematic map were obtained by correlating the spatial relationship between thematic map and the 25 locations of the 33 “known” KCR locations in WKF used for FR modelling. Cumulative FR value were obtained by carrying out overlay analysis of the thematic maps, which are classified into five classes by Natural Breaking method as (i)Very Low Favourable (VLF), (ii) Low Favourable (LF), (iii)Moderate favourable (MF), (iv)High Favourable (HF), and (v)Very High Favourable (VHF). The model was validated by ground verification at random sites and statistical method. During the ground visit, we observed KCR-like lithology’s at four new sites that have calcrete exposure at limited spatial extent and also some pieces of ultrabasic rocks similar to the explored sites. To ascertain their chemical composition of the samples were plotted in the MgO-K2O-Al2O3 ternary diagram. All the four samples fall in the Kimberlite/Lamproite field confirming them to be KCR. The FR predictive model was also validated statistically. Total 13 locations, including 8 site out of 33 known KCR locations, one newly discovered pipe by GSI and the four locations discovered during this study were used for the validation. Statistical validation shows that 84% of model accuracy is achieved. The study reveals that Lineament Intersection, and circular drainage anomaly in 3rd order streams, lineament density are significant themes in predicting KCR emplacement zones. The study demonstrates the utility of statistical based model such as FR model in predicting the location of KCR emplacement, even with statistically insignificant distribution of KCRs and can be applied elsewhere in the world to locate the KCRs. In the process, we report discovery of four new KCR pipes in the WKF.  相似文献   

4.
Remotely-sensed satellite data of Landsat 5 (TM) and IRS-1A (LISS II) covering parts of central portion of Chotanagapur plateau have been analysed visually to delineate some prominent lineaments in Ranchi district and its adjoining area. One of the most prominent lineament “Ranchi mega lineament? has been analysed in this paper. This lineament is a potential site for base metal mineralisation at some places, and it acts as good groundwater conduit in the region. No earlier attempt to map this entire structural unit as a separate entity is known. Geophysical bouguer gravity anomaly map, lithological and structural maps have some remarkable correlation with this lineament. In the present paper authors have tried to analyse the lineament with respect to its tectonic, mineralisation and groundwater prospects. Resistivity survey carried in close proximity of this lineament at selected sites, indicate that rocks are well fractured at depth. Available lithological and structural map support this lineament as a shear near Purulia (W.B.) and also having base-metal mineralisation potential in this area. Authors opine that existing gravity anomaly map may be further augmented in the light of present study.  相似文献   

5.
A comprehensive Landslide Susceptibility Zonation (LSZ) map is sought for adopting any landslide preventive and mitigation measures. In the present study, LSZ map of landslide prone Ganeshganga watershed (known for Patalganga Landslide) has been generated using a binary logistic regression (BLR) model. Relevant thematic layers pertaining to the causative factors for landslide occurrences, such as slope, aspect, relative relief, lithology, tectonic structures, lineaments, land use and land cover, distance to drainage, drainage density and anthropogenic factors like distance to road, have been generated using remote sensing images, field survey, ancillary data and GIS techniques. The coefficients of the causative factors retained by the BLR model along with the constant have been used to construct the landslide susceptibility map of the study area, which has further been categorized into four landslide susceptibility zones from high to very low. The resultant landslide susceptibility map was validated using receiver operator characteristic (ROC) curve analysis showing an accuracy of 95.2 % for an independent set of test samples. The result also showed a strong agreement between distribution of existing landslides and predicted landslide susceptibility zones.  相似文献   

6.
The study area is located near the town of Filippoi, north of the city of Kavala in northern Greece, known from ancient times for its rich gold mines, situated inside hydrothermal alteration zones (Fe–Mn oxide minerals). A Very High-Resolution (0.5 m pixel size) image of Worldview-2 satellite was digitally enhanced, yielding target areas of potential ore existence and lineaments. Ground-truth that followed digital image processing, revealed abandoned ancient mines, slags and ore occurrences. Also, a number of lineaments delineated on the satellite image were verified as faults.  相似文献   

7.
This study attempts to evaluate the capability of the advanced spaceborne thermal emission and reflection radiometer (ASTER) and the advantages of ground knowledge for generating maps portraying hydrothermally altered areas in relation to porphyry copper deposits. The northern part of the Rabor area in the Urumieh–Dokhtar magmatic belt, containing some copper mineralization occurrences, was investigated as a case study. Several image processing techniques, namely minimum noise fraction, pixel purity index, and n-dimensional visualization, contributed to the extraction of pure pixels as endmembers. The spectra of some rock samples collected around the well-known altered zones of the study area were resampled to ASTER bands and used to identify the image-extracted endmembers. Spectral analysis of the endmembers and ground sample spectra led to the identification of three types of hydrothermal alterations: (1) phyllic, (2) propylitic, and (3) argillic. The identified endmembers were used as the specified targets for mapping hydrothermal alteration zones over the study area by using a mixture tuned match filtering algorithm. Results demonstrate that high abundances within pixels correspond closely to the altered areas. Field observations, thin section, and X-ray diffraction of collected samples confirmed the accuracy of the alteration maps prepared by the application of the proposed methods. The final classified hydrothermal alteration maps showed the overall accuracy and kappa coefficient values of 85.41 and 0.72%, respectively. These results ascertain that ASTER data that use suitable image processing techniques appear consistent in mapping out the distribution of hydrothermally altered areas. In addition, ground knowledge data can act as a valuable information source to increase the image classification accuracy and reliability.  相似文献   

8.
Darrehzar porphyry copper deposit is situated in the Urumieh-Dokhtar magmatic assemblage of central Iran. In this paper, the integration of multiple geodata sets has been carried out using geographic information system for mapping lithology or hydrothermally altered rocks and also in selecting the best discriminating data elements for exploration of porphyry copper deposits located in areas with similar geological setting and climatic conditions. Principal component analysis is found useful for reducing large data sets into a few principal components. The integration of various geophysical data with SPOT image data through GIS has shown that the hydrothermal alteration and lithology can be mapped with more efficiency.  相似文献   

9.
Synoptivity and the exemplified fracture systems exhibited by the space borne imagery data has helped in solving many of the geological enigma in various parts of the world. The study conducted, using such remotly sensed data, in Jhalawar anticline, part of Proterozoic Cratonic Vindhyan Basin, Rajasthan, India, led to infer the history of tectonic evolution of peribasinal deformation which has been a matter of controversy for a century and more. In Landsat MSS data the Jhalawar region displays a panorama of lineaments and their analysis through azimuthal frequency diagrams, isofracture, lineament incidence and lineament intersection incidence density maps shows that the mean orientation of the lineaments fall in NW-SE and NE-SW and the shape of the various lineament density contours also show NE-SW and NW-SE orientations. In aerial photographs the area exhibits four sets of lineaments in NE-SW, NW-SE, N-S and E-W directions. Amongst these the former two sets are expressed as wide open master fracture systems with prolific vegetation fills along them and the latter two sets are characteristically observed as thin vegetation linears with frequent strike slip faulting along them. The further analysis of these fracture/lineament systems derived from multi-level remote sensing data shows that the Jhalawar anticline, which followed the pattern of flexural slip fold mechanism, was evolved by horizontally disposed σ1 (greatest principal stress) and 3σ (least principal stress) with the former oriented in NE-SW and the latter aligned in NW-SE directions with vertically disposed 2σ. The inference of such palaeostress environment of the Jhalawar region lead in the identification of a buried rigid basement high southwest of Jhalawar anticline, beneath the Deccan pile and loci of ground water, silica sand and probable igneous plug.  相似文献   

10.
Landslide hazard assessment at the Mu Cang Chai district; Yen Bai province (Viet Nam) has been done using Random SubSpace fuzzy rules based Classifier Ensemble (RSSCE) method and probability analysis of rainfall data. RSSCE which is a novel classifier ensemble method has been applied to predict spatially landslide occurrences in the area. Prediction of temporally landslide occurrences in the present study has been done using rainfall data for the period 2008–2013. A total of fifteen landslide influencing factors namely slope, aspect, curvature, plan curvature, profile curvature, elevation, land use, lithology, rainfall, distance to faults, fault density, distance to roads, road density, distance to rivers, and river density have been utilized. The result of the analysis shows that RSSCE and probability analysis of rainfall data are promising methods for landslide hazard assessment. Finally, landslide hazard map has been generated by integrating spatial prediction and temporal probability analysis of landslides for the land use planning and landslide hazard management.  相似文献   

11.
GIS. a potential tool for facilitating the generation and use of thematic information, has been applied to groundwater potentiality of the Shamri micro-watershed in Shimla Taluk. The role of various parameters, namely, drainage. lineament. lithology . slope and landuse have been emphasised for delineation of groundwater potential iones. IRS-I C IAN and LISS Ill FCC merged satellite images on 1:25000 scale and Topographic map no. 53L/4 SI together with field traverses have been used as the data source. A multi-criteria evaluation following probability weighted approach has been applied for overlay analysis that allows a linear combination of weights of each thematic map with the individual capability value. 1 he resultant map indicates a high groundwater potentiality in the flood plains, river terraces and river channels in the vicinity of the Shamri nala. Other sites of high potentiality include places showing break in slopes and criss-crossing of lineaments.  相似文献   

12.
The South Armorican shear zone is one of the major occurrences of Variscan basement in Europe. The objectives of the study were to compile a lineament and a structural map from remotely sensed SPOT imagery. Transparent color films, enhanced by high-pass filtering and by stretching color composites, and spatial filtered images were analysed. The major structure mapped corresponds to a dextral transcurrent shear belt in which C and S axes have been described. Late Paleozoic and Tertiary fracturations truncate these structures. The localisation, extension and geometry of granite domes were also precised. Lastly, this study provides a good example of structural interpretation of a moderate-relief terrain using high-resolution SPOT imagery.  相似文献   

13.
遥感线性体场的数量化分析   总被引：13，自引：0，他引：13  
遥感线性体场是地质构造场和成矿地质场在地球表面和光谱特征上的反映。本文从地质异常场和线性体场的概念出发,利用图像处理技术,较系统地研究了线性体的数据处理方法,建立了线性体场的数量化分析模式:（1）线性体场总体统计特征的计算和图示;（2）线性体场的数字表征;（3）线性体场的数学分析。并以铜陵地区为例,介绍了线性体场的数量化分析方法在地质构造分析和成矿预测中的应用。  相似文献   

14.
本文以福建省高盖山隧道区线性构造为研究对象,对其进行了分形特征研究。应用GIS和RS技术对该区的SPOT遥感影像进行线性构造信息的提取,利用线性构造分布图,使用盒计维数法计算该区线性构造的分维值。结果表明,高盖山隧道区线性构造具有分形特征,根据岩体工程质量标准,研究区应属"好"的级别,对于铁路隧道的建设较为有利。分形理论为线性构造的研究提供了定量化的技术手段,并可为相关工程地质评价提供一个量化的指标。  相似文献   

15.
A set of techniques was developed for automatically detecting tectonic lineaments from multi-source remotely-sensed data at various scales. The techniques include adaptive shading of grid data to enhance linear features, a segment-tracing algorithm to extract line segments from the shaded grid data, grouping of the segments by concatenating short segments, and connecting them by proximity and co-linearity criteria to form a lineament that represents significant tectonic structure. B-spline smoothing was adopted for lineament representation. Finally, a technique for assessing the orientations and styles of faulting (normal, reverse, and strike-slip types) was developed for use in characterizing the extrapolated fracture planes. The applicability of the developed techniques was examined using 30 arc-second topography/bathymetry grids, 1-min gravity anomaly grids, and 2-min total field magnetic intensity grids covering Egypt and its surroundings. Lineaments derived from data types so diverse in composition and from various depths corresponded well with the referenced tectonic features over much of the region. Prominent trends and faulting styles of lineaments provided important clues as to the timing of their development as well as strong support for a structural inheritance model. Results demonstrated the effectiveness of the developed techniques combined with integration of remotely-sensed data in detecting regional fracture systems accurately and in characterizing geodynamics over a long timeframe.  相似文献   

16.
A geostatistical analysis of the remotely-sensed lineament fabric data associated with the North Almora Thrust of Garhwal Himalaya has been carried out The analysis of data provided 18 major orientations of the lineament density girdles. Further statistical treatment of these derived lineaments using the method of analysts of directional data indicates that the lineaments can be classified into genetic groups. The result indicates that the North Almora Thrust and Kaliasaur Fault are not genetically related and occurred in separate phases of tectonic activities. The results also show that the Alaknanda river is flowing through a tectonically-controlled valley. The study suggests the suitability of statistical methods in lineament-fabric-data analysis for tectonic interpretations.  相似文献   

17.
A systematic statistical analysis of the lineament fabric data associated with the Great Boundary Fault of Rajasthan provides 26 axes of high density girdles. Further statistical treatment of these isolated axes following the methods of analysis of directional data indicates that the lineament can be classified into genetic categories. The result indicates that the Great Boundary Fault and the Chambal Fault are genetically related and that the majority of the lineaments are the result of the reactivation of the Great Boundary Fault under a southward directed dominant stress field.  相似文献   

18.
The study of lineament pattern based on IRS-IA sub-scene (P24–R50) and Landsat (P143– R42) data combined with the drainage analysis and field observations, two prominent sets of lineament (NE-SW and NNW-SSE), besides less prominent E-W and N-S trending lineaments of tectonic origin have been observed in parts of Allahabad area. Pervasive and penetrative sub-vertical joint sets parallel to the macroscopic linear structures along with collapse structures possibly of neotectonic origin are also noted in the basement rock exposed to the SSW of Allahabad. The development of various meso- and macroscopic deformed structures, presence of collapse structure in the basement strata and the near orthogonal channel shift of axial rivers provide evidence of basement reactivation in parts of Allahabad area, Ganga plain in space and time.  相似文献   

19.
The study area comprises Bundelkhand Granite of Archaean age in the east, unconformably overlain by Upper Vindhyan sequence, ranging from Upper Kaimur Sandstone to Lower Bhander Sandstone Groups, in the west. Geomorphologically, the area has been divided into three geomorphic provinces viz. (1) Bundelkhand inselberg — pediplain, (2) Vindhyan structural plateau, consisting of two major sub-levels of Upper and Lower Bhander Sandstone Groups and two minor sub-levels of Upper and Lower Rewa Sandstone Groups, separated by escarpment and/or valleys, and (3) Chambal alluvial plain. Photo-interpretation and field studies indicate that there are three sets of lineament trends in the area out of which the NNW-SSE trend comes out very strongly on imagery and is correlatable with basement fracture trend of Bundelkhand massif. The synoptic view through imagery also gives the impression that the course of Chambal river towards north and west is controlled by a major lineament, possibly a regional fault trending NE-SW. The NNW-SSE lineament trend mentioned above then probably reflects tension release aspect of the faulting. The field check has brought out some very broad, gentle warps also with NNE-SSW trend in the area. The paper presents the salient observations on geological, structural and geomorphological studies for Shivpuri area based on remote-sensing techniques and their utility for such regional investigations.  相似文献   

20.
Integration of satellite remote sensing data and GIS techniques is an applicable approach for landslide mapping and assessment in highly vegetated regions with a tropical climate. In recent years, there have been many severe flooding and landslide events with significant damage to livestock, agricultural crop, homes, and businesses in the Kelantan river basin, Peninsular Malaysia. In this investigation, Landsat-8 and phased array type L-band synthetic aperture radar-2 (PALSAR-2) datasets and analytical hierarchy process (AHP) approach were used to map landslide in Kelantan river basin, Peninsular Malaysia. Landslides were determined by tracking changes in vegetation pixel data using Landsat-8 images that acquired before and after flooding. The PALSAR-2 data were used for comprehensive analysis of major geological structures and detailed characterizations of lineaments in the state of Kelantan. AHP approach was used for landslide susceptibility mapping. Several factors such as slope, aspect, soil, lithology, normalized difference vegetation index, land cover, distance to drainage, precipitation, distance to fault, and distance to the road were extracted from remotely sensed data and fieldwork to apply AHP approach. The excessive rainfall during the flood episode is a paramount factor for numerous landslide occurrences at various magnitudes, therefore, rainfall analysis was carried out based on daily precipitation before and during flood episode in the Kelantan state. The main triggering factors for landslides are mainly due to the extreme precipitation rate during the flooding period, apart from the favorable environmental factors such as removal of vegetation within slope areas, and also landscape development near slopes. Two main outputs of this study were landslide inventory occurrences map during 2014 flooding episode and landslide susceptibility map for entire Kelantan state. Modeled/predicted landslides with a susceptible map generated prior and post-flood episode, confirmed that intense rainfall throughout Kelantan has contributed to produce numerous landslides with various sizes. It is concluded that precipitation is the most influential factor for landslide event. According to the landslide susceptibility map, 65% of the river basin of Kelantan is found to be under the category of low landslide susceptibility zone, while 35% class in a high-altitude segment of the south and south-western part of the Kelantan state located within high susceptibility zone. Further actions and caution need to be remarked by the local related authority of the Kelantan state in very high susceptibility zone to avoid further wealth and people loss in the future. Geo-hazard mitigation programs must be conducted in the landslide recurrence regions for reducing natural catastrophes leading to loss of financial investments and death in the Kelantan river basin. This investigation indicates that integration of Landsat-8 and PALSAR-2 remotely sensed data and GIS techniques is an applicable tool for Landslide mapping and assessment in tropical environments.  相似文献   

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