首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 718 毫秒
1.
Photogeological studies of the area shows the presence of four major lithological groups as : 1. Precambrian basement made up of granitic gneisses and Charnockites, 2. The Utatur Group of rocks, 3. The Trichinopoly Group of rocks and 4. The Ariyalur Group of rocks. Some prominant lineaments roughly trending in NE-SW direction are seen. These lineaments represent the traces of the reactivated faults in the basemeht. The photogeological studies were supplemented by morphometric analyses. It is seen that the drainage in lower order basins is controlled by structure, i.e. by the strike of the rocks and faults in the basement. The higher order streams apparently follow the direction of regional gradient.  相似文献   

2.
Remote sensing techniques using satellite imagery have proved to be an indispensible tool in morphometric analysis and groundwater studies. In the present area, morphometric analysis using temote sensing techniques have been carried out in Chaka river sub-basin of Manbazar Block, Purulia district, West-Bengal, which is one of the most drought affected area in West-Bengal. The parameters worked out include Bifurcation ratio (Rb), Stream length (Lu). Form factor (Rf), Circulatory ratio (Rc), and Drainage density. The morphometric analysis suggests that the area is covered by fractured, resistant, permeable rocks, the drainage network not so affected by tectonic disturbances. Using satellite imageries of LANDSAT and IRS, different hydrogeomorphological units have been delineated. The study shows that moderately weathered pediplains and valley fills are good prospective zones for groundwater exploration.  相似文献   

3.
石火生  林珲  王长林 《遥感学报》2002,6(6):517-522
低序次断裂是地壳变形的直接产物，具有丰富的构造变形信息，经过转换的低序次构造。形式多样，图案复杂，是构造研究的重要对象，也是地表稳定性研究的重要基础。利用香港地区航空雷达图像资料，提取其中低序次构造的弱信息，建立转换变形模型，以分析区内不稳定地表的构造背景。区内北东向断裂是主要构造，其右行剪切形成一系列低序次R面，P面，R^1面构造，在雷达图像上表现为线性弱信息并且与微地貌发育有关。利用线性构造增强，提取技术和低序次构造组合分析方法，结合野外地质调查，确定马鞍山地区EW向的张性破裂是NE向张剪断裂的转换，是造成马鞍山滑坡的重要地质因素。  相似文献   

4.
The geological studies of the eastern parts of Harda-Barwah basin covering about 3000 sq. km area on 1∶50,000 scale have been carried out using satellite imagery of IRS (FCC), supplemented by Landsat TM/MSS scences and air photos. The present studies with the aid of satellite imagery and remote sensing techniques have brought out the regional stratigraphy and structure of the area and helped in deciphering the interrelationship of various rock groups in the Narmada lineament zone. The area comprises Archaean/Proterozoic gneisses, the Mahakoshal volcano sedimentary suite, the Harda granitoids, the Bijawar Group and the rocks of Vindhyan Supergroup, Deccan Trap and Quaternary sediments. The Archaean/Proterozoic rocks comprising gneisses and schist form basement. The Mahakoshal Group of rocks occur along the ENE-WSW to E-W trending Narmada lineament zone and comprise foliated quartzite, actinolite-chlorite-sericite phyllite and metabasics. The Harda granitoids showing intrusive relationship with earlier rocks, comprise coarse-grained crudely foliated grey to pink granites, fine to medium grained homogeneous granites and porphyritic granites. The Bijawar Group comprises quarzite, chert breccia and dolomite in the order of younging and shows unconformable relationship with the Mahakoshal and the Harda granitoids. The Bijawar rocks show doubly plunging major synformal structure and numerous sympathetic minor folds along ENE-WSW to E-W axis and cross folds along NW-SW axis. The Bijawar rocks are unconformably overlain by a sequence of sandstone and shales belonging to the Rewa Group of the Vindhyan Supergroup. The Deccan Trap lava flows represent the last igneous activity in the area. The Quaternary deposits comprising a cyclic sequence of sand, silt, clay and rock gravels of the Narmada river represent the youngest formation of the area.  相似文献   

5.
应用卫星数字图像研究达拉布特断裂   总被引：1，自引：0，他引：1  
通过对卫星数字图像的解译和地质特征的研究,提出了呈北东向横贯于西准噶尔的达拉布特 断裂是一长达480km具多期活动的大断裂带。 该断裂对下石炭统及其以前的地层无任何控制作用,只可见左行错断；对中石炭统到下、中 侏罗统的地层具有明显的控制作用；达拉布特超基性岩带中的超镁铁岩体是受推覆构造的影响而 就位于达拉布特断裂的上盘。 本断裂带的形成发育是由于早石炭世以后,碰撞后的西伯利亚、哈萨克斯坦和塔里木三大陆 块仍在不断地相向运动,作为一种应力的释放形式,其早期以左行陡倾的走滑断层形式开始形 成；中期(三叠纪──早、中侏罗世)受陆内俯冲作用的影响,被强烈的推覆构造改造成上陡下 缓的犁状断层；挽近时期,断裂处于引张状态,表现为上盘下降的正断层性质,形成目前表现明 显的断层地貌。  相似文献   

6.
Ground water is an excellent solvent, which dissolves chemicals ions as it moves through rocks and subsurface soil. This leads to more mineralization in groundwater than surface water. The objective of the present study is to examine the groundwater quality of the Paravanar River Sub-basin, Cuddalore district, Tamil Nadu, India. The Electrical Conductivity (EC) values ranges between 160 and 2,580 μS/cm in groundwater samples. The highest value of 2,580 μS/cm was recorded in wells near the coast. pH values ranges from 7.2 to 8.6. NNE and southern part of the study area has low pH values, rest of the area represents the alkaline nature of groundwater. In south eastern part of the study area alkali values are slightly higher but it is within WHO’s tolerable limits. The spatial distribution of chloride concentration shows that Meenatchipettai, Vazhisothani palayam and Allapakkam represents maximum Cl2 concentration of 527, 320 and 374 ppm, which is above ISI drinking standards of 250 ppm. Increase in isochlore is observed from the coast up to the Neyveli lignite mine. Nitrate concentration of groundwater samples ranges from 0.1 mg/l to 64 mg/l. As most of the study area is cultivated, fertilizers used for agriculture may be the cause for increase in concentration of nitrates in few concentrated locations.  相似文献   

7.
The general tendency of mapping groundwater resource using remote sensing and Geographic Information System (GIS) techniques involve assigning higher weightage to geomorphology. But this cannot be used as a thumb rule everywhere, especially an area where many ductile and brittle zones are prevalent. The influence of texture and structure of sheared rocks might play a control over retaining and permitting groundwater to flow. Attur valley is characterized by the presence of many shear zones and faults and hence the rocks are highly fissile within the shear zones. The present study tries to establish a new ranking and weightage scheme and hence a new spatial model for groundwater resource mapping in shear zone area like Attur Valley. This spatial model can be verified with field data such as water level data, pump test and resistivity data.  相似文献   

8.
Laboratory reflectance spectra of 18 rock samples from the Precambrian basement of north east of Hajjah were measured and analyzed using the instrument of FieldSpec3 with spectral range 0.250–2.500 μm. The aim of this study is to use the spectral reflectance of rocks for mapping the mineral resources in the north east of Hajjah. The altered system in the study area comprises of silicification, sericitification, oxidation, clay minerals and carbonatization. Silicified alteration is not distinguishable in the regions of Visible-Near Infrared (VNIR) and Short wave Infrared (SWIR) of the electromagnetic spectrum, because of lack of diagnostic spectral absorption features in silica in this wavelength. Although the arsenopyrite and pyrite are wide spread in the whole study area their features do not appear in any range of spectra because they exhibit trans-opaque behavior and often lack distinction in VNIR and SWIR. The entire spectral reflectance curves of samples show alteration. Based on the examination of laboratory spectra all samples in the study area show promise in the field of mineral resources.  相似文献   

9.
Geological studies of the area around Katta, in the southern part of the Ratnagiri District of Maharashtra, were carried out with the help of visual remote sensing techniques using LANDSAT imageries on 1:250,000 scale and aerial photographs on 1:60,000 scale. The major stratigraphic units represented in the area under study are the Archean Complex, Kaladgi Supergroup, Deccan Trap, Laterite and Alluvium. The Kaladgis unconformably overlie the Archean metasediments and also at places exhibit faulted contacts with the latter. The major part of the area is covered by a thick evergreen vegetation. The interpretation followed by field work and laboratory work revealed the following:
  1. The different lithologic units could be delineated on the aerial photographs.
  2. Different lineaments marked on the imagery were found to be due either to faults or fracture zones. Some of the older faults appear to have been rejuvenated after the formation of the laterites.
  3. Some of the lithologic horizons can be identified on the Landsat imagery by virtue of their spatial signatures.
These studies indicate that even in the area covered with thick vegetation, aerospace imagery in appropriate band and data scale can provide significant geological information.  相似文献   

10.
The rough terrain between the Gogar Dhar (Mandi-Brot rise) and the Kullu-Larji valley is geologically unexplored. This paper brings out for the first time the geology and regional tectonic set-up of the area on the basis of LANDSAT imagery interpretation and field checks. Image analysis of about 3700 sq. km area and field observations along selected sections of the area reveal that the area mainly comprises mica-chlorite schists, quartzites and phyllites i.e. low to medium grade Chail metamorophics with acid and basic intrusions within them. Structually the rocks are arranged in the form of a NNW-SSE trending faulted synclinorium, the axis of which passes through Daggi Dhar. The western flank of the synclinorium is more strongly folded. Granitoids and basics show concordent relations with the country rocks. Two belts of granitoids are found occupying the cores of the folds on both the limbs of the synclinorium. Along the Uhl river (in the Chauhar valley) and the Kullu valley passes the Chail thrust separating the Chail metamorphics from the rocks of the outer carbonate belt and the traps of the Mandi unit, and the inner carbonate belt of the Larji window zone respectively. The area is dissected into blocks by cross cutting, deep-seated major faults of three generations. The fold and fault systems have prominent control over the geomorphology including the drainage patterns and landforms of the area. The present area is a typical case of inverted relief, anticlinal valleys and synclinal hills being the main geomorphic features developed due to structural control. The change in the course of the Beas River between Mandi and Pandoh is a typical case of structural control on the present drainage system.  相似文献   

11.
Quantitative estimations of the fractional cover of photosynthetic vegetation (fPV), non-photosynthetic vegetation (fNPV) and bare soil (fBS) are critical for soil wind erosion, desertification, grassland grazing, grassland fire, and grassland carbon storage studies. At present, regional and large-scale fPV, fNPV and fBS estimations have been carried out in many areas. However, few studies have used moderate resolution imaging spectroradiometer (MODIS) data to perform large-scale, long-term fPV, fNPV and fBS estimations in the Xilingol grassland of China. The objective of this study was to quantitatively estimate the time series of fPV, fNPV and fBS in the typical grassland region of Xilingol from MODIS image data. Field measurement spectral and coverage data from May and September 2017 were combined with the 8-day composite product (MOD09A1) acquired during 2017. We established an empirical linear model of different non-photosynthetic vegetation indices (NPVIs) and fNPV based on the sample scale. The linear correlation between the dead fuel index (DFI) and fNPV was best (R2 = 0.60, RMSE = 0.15). A normalized difference vegetation index (NDVI)-DFI model based on MODIS data was proposed to accurately estimate the fPV, fNPV and fBS (estimation accuracies of 44%, 71%, and 74%, respectively) in the typical grasslands of Xilingol in China. The fPV, fNPV and fBS values for the typical grassland time series estimated by the NDVI-DFI model were consistent with the phenological characteristics of the grassland vegetation. The results show that the application of the NDVI-DFI model to the Xilingol grassland is reasonable and appropriate, and it is of great significance to the monitoring of soil wind erosion and fires in grasslands.  相似文献   

12.
Photogeologic mapping of a sample area defined by latitudes 24° O to 6′N and longitudes 73° 30′ to 45′ E from a part of the Aravalli orogen, illustrates the advantages, as well as limitations, of photo-interpretation (PI) in terrains comprsing, highly deformed ancient rock formations. Discrimination between psammitic and pelitic metasediments is easy, using micro-relief and drainage parameters as PI elements; but that between pelites, ultra-basic schists and impure marbles is difficult and less reliable. Trends of foliations, several sets of joints and faults are distinct on the aerial photographs, but complete reconstruction of the superposed fold geometry is not possible. Within the area studied, dominantly pelitic, psammitic and a little clacareous metasediments, intruded by ultra-basics, exhibit a prominent and persistent NNE trend defined by lithologic contacts, bedding and foliations, with steep northwesterly dips. In its central part, bands of psammites within the pelites exhibit a hook shaped fold interference pattern (type 3 of Ramsay, 1967) with the later upright (Fleuty, 1964) fold axial trace trending northwesterly.  相似文献   

13.
The study area around Saidnagar falls in Bundelkhand granitic terrain forming buried pediplain (granite derived material). The occurrence and movement of groundwater is restricted to the unconsolidated material, weathered and fractured rock. For the selection of tube-well sites, geoelectrical resistivity investigations have been carried out at the sites which are found suitable based on remote sensing and hydrogeological studies. Twenty six Vertical Electrical Soundings (VES) have been carried out by using Schlumberger electrode configuration, which have brought out 3 and 4 layered sub-surface sections. The resistivity of water-bearing weathered/fractured rocks varies from 10 to 20 ohm m, with thickness ranging from 3.4 to 75.0 m. The depth to the basement is found ranging between 6.8 and 93.0 m The integrated studies have revealed that the northern part of the study area forms groundwater prospective zone, consisting of unconsolidated water-bearing weathered material, In the southern part of the study area, weathered layer is either thin or absent and the groundwater movement and storage is restricted to the weathered/fractured zone only. This zone extends down to a depth of 3.4 to 75.0 m and may yield sufficient amount of water since it gets recharged by direct infiltration due to precipitation and percolation through Nalas.  相似文献   

14.
Gondwana-derived terranes are now separated by major faults or suture zone, which are rarely simple and easily recognizable lineaments. Different association of ore mineral systems such as deposits of sediment-hosted/orogenic gold and granite-related minerals is discovered in collision and subduction zones of the Gondwana-derived terranes. They are associated with large-scale, terrane-bounding fault systems and broad areas of deformation. Mineralization mostly associated with structurally-controlled complex lodes, veins, sheeted veins and veinlets in diverse orientations. Recognizing the structural significance of lineaments and curvilinear is very difficult in tropical, arid and Antarctic regions due to environmental obstacles. Remote sensing data could be used to detect geological structures associated with suture zones between Gondwana-derived terranes especially for large inaccessible regions where fieldwork is limited or nonexistent. In this investigation, the Phased Array type L-band Synthetic Aperture Radar (PALSAR) satellite remote sensing data were used to map major geological structures in the Bentong-Raub Suture Zone of Peninsular Malaysia. It is one of the major structural zones in Sundaland, Southeast Asia, which forms the boundary between the Gondwana-derived the Sibumasu terrane and Sukhothai-Indochina arc. Structural features associated with sediment-hosted/orogenic gold deposits in the Central Gold Belt and tin mineralization in S-type granites in the Main Range were investigated using PALSAR data and comprehensive fieldwork. Results indicate that main faults strike along 340° to 350° that are intersected by many shear or lateral fault zones are high potential zone for gold mineralization in the Central Gold Belt. Hydrothermally alteration mineral zones and cataclastic rocks are also the other indicators of gold mineralized veins in the gold belt. High potential zones for tin mineralization are N–S strike-slip faults, fault zones and shear zones trending E–W, NE–SW and WNW–ESE in dissected crystalline granitic rocks that are associated with hydrothermal alteration zones in the Western Tin Belt. Lineament analysis using PALSAR satellite remote sensing data is a useful tool for mapping major geological structural features and detection of the boundary between the Gondwana-derived terranes and detailed structural analysis of fault systems and deformation with high potential for a variety of mineral resources, especially in tropical, arid and Antarctic regions.  相似文献   

15.
The Bundi-Indergarh sector in southeast Rajasthan is characterized by folded and faulted Vindhyan rocks that are exposed as NE-SW trending long parallel ridges. The sector is separated from older rocks by the Great Boundary Thrust and is traversed by younger cross faults at several localities. The thematic maps of geomorphology, slope, vegetation index and morphotectonic parameters of Bundi-Indergarh sector have been prepared using IRS ID L1SS III and WiFS and, Landsat ETM digital data. These theme are integrated in GIS environment to assess the neotectonic potential in the area. The neotectonic potential map of the sector has been generated that indicates relative potential values as high (55–85), medium (35–55) and low (5–35) on 100-point scale. The observed four high potential zones in the area are located at the intersection of NE-SW and NW-SE lineaments. The study brings out methodology for assessing active tectonic potential of the area.  相似文献   

16.
Geospatial themes namely geology, topography and classified satellite image of the area in and around Ravipadu gabbro pluton (RGP), Prakasam alkaline province, Andhra Pradesh has been studied. The geological map of co-magmatic suite of RGP predominantly exposes olivine gabbro followed by olivine norite, troctolite and anorthosite. Graphic portrayal of the attributes such as mineralogical (modal) and chemical compositions of rocks of RGP is supplemented in the map display. The topography reveals that the terrain is flat and that it underwent differential erosion thereby exposing the deeply eroded RGP flanked on the North and South by two hilly mounds composed of cordierite-garnet gneiss (metapelite). Digital analysis of satellite image (IRS-1D) of the Ravipadu area, based on the spatial and spectral characteristics producing a classified image superposing on the vectorised geological map of the gabbroic body on a spatially referenced base, reveal a near perfect match of the two digital data products.  相似文献   

17.
吴浩  王先华  叶函函  蒋芸  段锋华  吕松 《遥感学报》2019,23(6):1223-1231
大气温室气体监测仪GMI（Greenhouse gases Monitor Instrument）是高分五号（GF-5）卫星载荷之一，主要用于全球温室气体含量监测和碳循环研究。高精度反演是卫星大气CO2遥感的基本需求。地表反射率影响卫星遥感辐射量及辐射传输过程中的地气耦合过程，严重制约着CO2的反演精度，针对GMI开发高精度的大气CO2反演算法，地表反射是一个需要重点考虑的因素。城市是CO2重要的发射源，且城市下垫面存在明显的二向反射特性，加上城市大气条件不良，复杂的地气耦合效应存在这都考验反演算法的准确性和鲁棒性。本文针对北京城市地区，利用2011年—2016年共5年的MODIS（MODerate-resolution Imaging Spectroradiometer）地表二向反射分布函数BRDF（Bidirectional Reflectance Distribution Function）数据，构建了适合利用单次观测数据反演的BRDF模型，并提出一种同时反演地表BRDF参数和大气CO2含量的算法。结果表明在550 nm波长处气溶胶光学厚度AOD（Aerosol Optical Depth）小于0.4时，大部分GMI模拟数据的反演误差控制在0.5%（~2 ppm）内。利用GOSAT （Greenhouse gases Observing SATellite）实测数据的反演结果与修正后的日本国立环境研究所NIES（National Institute for Environmental Studies）反演结果进行对比，其平均误差为1.25 ppm，相关性达到0.85。本算法满足GMI数据在北京城市区域高精度CO2反演的需求，并使得反演高值气溶胶区域数据成为可能，增加了GMI观测数据的利用率。  相似文献   

18.
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   

19.
利用渭河盆地2001~2010年高精度GPS监测资料,采用有限元数值分析法,分析了渭河盆地内深大断裂处的构造应力特征及断裂活动特性。结果表明,盆地西部断裂处均呈现出明显的近E-W（east-west）向挤压应力特征,而盆地中部断裂处则均呈现出显著的NW-SE（northwest-southeast）向拉张应力特征,东部断裂处呈现出一定的NW-SE向拉张应力,但该部量值较中部断裂处小;走向各异的同一条深大断裂不同区段,呈现出的应力特征、量值以及活动速率也存在差异性;跨断裂剖线显示沿断裂走向的速度分量在断裂两侧均发生了一定量值的变化,构造断裂具有一定的扭动特性。模拟计算结果进一步显示盆地中部较东、西部受NW-SE向拉张应力作用显著,且在中部这些具有拉张应力特征的深大断裂交汇处,特别是断裂活动速率较大的区段,正是盆地内地裂缝灾害最为集中发育的区域。  相似文献   

20.
Aerial remote sensing coupled with selective field check was carried out to assess the feasibility of the Srinagar dam site, related construction works, location of Srinagar Thrust and to evaluate terrain factors that may have adverse influence on the life of the structure. The lithology of the area comprises mainly of quartzites, phyllites, basic rocks and limestones which trend WNW-ESE. The Srinagar Thrust following the regional trend passes through the centre of the area. The investigation has established the location and extension of Srinagar Thrust and other faults, and presently dormant state of Srinagar Thrust. It also links the major Kaliasaur landslide with a fault. There is a possibility that the slide would contribute a substantial amount of silt into the reservoir.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号