The integration of remotely sensed data allowed the successful characterization of the mineral alteration zones of the Oudiane Elkharoub area in the Northeastern part of Reguibat Shield using image transformation tech...The integration of remotely sensed data allowed the successful characterization of the mineral alteration zones of the Oudiane Elkharoub area in the Northeastern part of Reguibat Shield using image transformation techniques. As both chemical and geochemical analyses showed significant Au, Ag, Cu, Pb, Mn, Cr, Ni, Th and Y anomalies, it’s very interesting to apply the remote sensing and GIS in mineral resources mapping. The remote sensing is a direct adjunct to the field, lithologic and structural mapping, and more recently, GIS has played an important role in the study of mineralization areas. The integration of several evidential maps highlighted the plausible areas with high concentrations of chlorite, epidote, kaolinite, calcite, alunite, hematite, illite and sulfur among other key mineral alterations that reflect the intensity of hydrothermal effects and the probable sites of ore bodies. The methodological approach integrates geological information acquired from Aster and Landsat 8 OLI/TIRS (Operational Land Imager/Thermal InfraRed Sensor) images and a multi-criteria GIS analysis. The superimposition of various lineament and hydrothermal alteration maps and the consideration of precious and base metal indicators allowed the zoning of sites likely to contain mineral concentrations. Remote sensing becomes an important tool for locating mineral deposits in its own right, when the primary and secondary processes of mineralization result in the formation of spectral anomalies. Reconnaissance lithological mapping is usually the first step of mineral resource mapping. This is complimented with structural mapping, as mineral deposits usually occur along or adjacent to geologic structures, and alteration mapping, as mineral deposits are commonly associated with hydrothermal alteration of the surrounding rocks. Ground truthing and laboratory studies including XRD analysis were utilized to verify the results.展开更多
Drainage responds rapidly to tectonic changes and thus it is a potential parameter for teetonogeomorphological analysis. Drainage network of Potwar is a good geological record of movement, displacements, regional upli...Drainage responds rapidly to tectonic changes and thus it is a potential parameter for teetonogeomorphological analysis. Drainage network of Potwar is a good geological record of movement, displacements, regional uplifts and erosion of the tectonic units. This study focuses on utilizing drainage network extracted from Shuttle Radar Digital Elevation Data (SRTM-DEM) in order to constrain the structure of the Potwar Plateau. SWAN syncline divides Potwar into northern Potwar deformed zone (NPDZ) and southern Potwar platform zone (SPPZ). We extracted the drainage network from DEM and analyzed 112 streams using stream power law. Spatial distribution of concavity and steepness indices were used to prepare uplift rate map for the area. DEM was further utilized to extract lineaments to study the mutual relationship between lineaments and drainage patterns. We compared the local correlation between the extracted lineaments and drainage network of the area that gives us quantitative information and shows promising prospects. The streams in the NPDZ indicate high steepness values as compared to the streams in the SPPZ. The spatial distribution of geomorphic parameters distinctive deformation and uplift rates suggest the among eastern, central and western parts. The local correlation between drainage network and lineaments from DEM is strongly positive in the area within I km of radius.展开更多
This paper presents a lineament detection method using multi-band remote sensing images. The main objective of this work is to design an automatic image processing tool for lineament mapping from Landsat-7 ETM + satel...This paper presents a lineament detection method using multi-band remote sensing images. The main objective of this work is to design an automatic image processing tool for lineament mapping from Landsat-7 ETM + satellite data. Five procedures were involved: 1) The Principal Component Analysis;2) image enhancement using histogram equalization technique 3) directional Sobel filters of the original data;4) histogram segmentation and 5) binary image generation. The applied methodology was contributed in identifying several known large-scale faults in the Northeast of Tunisia. The statistical and spatial analyses of lineament map indicate a difference of morphological appearance of lineaments in the satellite image. Indeed, all the lineaments present a specific organization. Five groups were classified based on three orientations: NE-SW, E-W and NW-SE. The overlapping of lineament map with the geologic map confirms that these lineaments of diverse directions can be identified and recognized on the field as a fault. The identified lineaments were linked to a deep faults caused by tectonic movements in Tunisia. This study shows the performance of the satellite image processing in the analysis and mapping of the accidents in the northern Atlas.展开更多
Sinai Peninsula has fascinating geologic setting and is displaying a diversity of structural lineaments that have greatly influenced the distribution of natural resources and hazards. Shaded relief images derived from...Sinai Peninsula has fascinating geologic setting and is displaying a diversity of structural lineaments that have greatly influenced the distribution of natural resources and hazards. Shaded relief images derived from SRTM-DEM mosaics were used for the identification, extraction, and mapping of these structural lineaments. Statistical parameters particularly, azimuth frequency, lineament intersection, lengths, and density distribution were analyzed using SPSS software. Two additional new statistical indices;Lineament Relative Abundance Index (LRAI) and Lineament Majority-Minority Index (LMMI) were applied. Moreover, the distribution of the different statistical parameters was illustrated as contour maps through GIS environment. Basically, two dominant clusters;NW-SE and NNE-SSW trends were detected. These trends are related to major fracture systems that are characterized by extensive mean lengths and high proportion values. Furthermore, the northern and central parts of Sinai Peninsula have lower density and intersection of structural lineaments that gradually increase towards the southern part. However, the northern part of Sinai displays wider areas of majority zones than the southern part. This could be attributed to the lower density of lineaments and little tendency for multiple lineament populations. The majority zones are usually associated with NE and NW-SE in the northern part of Sinai, whereas the majority zones are of less abundance in the central and southern parts of Sinai due to the multiple orientations of lineament populations which reduce the tendency for majority. Eventually, the results of the present work could be applicable in the different geologic and environmental aspects that are based on a good understanding of the genetic and spatial relationships of fracture systems. These aspects encompass geodynamics, exploration for mineralization and groundwater, in addition to the mitigation of natural hazards such as flush flooding and earthquakes.展开更多
East Azarbaijan belongs to the Iranian plateau and is part of lesser Caucasus province. Studied area is located in west-central Alborz. The intrusion of oligocene bodies in various units causes the alteratio...East Azarbaijan belongs to the Iranian plateau and is part of lesser Caucasus province. Studied area is located in west-central Alborz. The intrusion of oligocene bodies in various units causes the alteration and mineralization in northwest of Iran. The Hizejan-Sharafabad is one of this named mineralized zone. Granitoidicrocks with component of Granodiorite to alkali have been influenced by hydrothermal fluids. Fractures and faults are as weak zone in earth surface and hydrothermal fluids rise to surface by these geological structures. These solutions cause to alteration in host rocks. Alteration zones are important features for the exploration of deposits. The altered rocks have specific absorption in some spectral portion and ASTER sensor is able to identify the type of alteration. Remote sensing method is useful tool for discovering altered area. The purpose of this study is to appraise ASTER data for surveying altered minerals in Hizejan-Sharafabad area in the event of detecting the potential mineralized areas. In this research, False Color Composite (FCC), Band ratio, and color composite ratio techniques are applied on ASTER data and Silica, Argilic, and Propylitic alteration zones are detected. These alteration types and mineralized area are related to Hizejan–Sharafabad fault which is absent in the fault maps. ASAR image processing has been used for lineaments and faults identified by the aid of Directional and Canny Algorithm filters. The structural study focuses on fracture zones and their characteristics including strike, length, and relationship with alteration zones.展开更多
The study area that is part of Tarom volcano-plutonic zone which host many hydrothermal base metal deposits located in Zanjan, NW Iran. Understanding the tectonic events that can cause mineralization and hydrothermal ...The study area that is part of Tarom volcano-plutonic zone which host many hydrothermal base metal deposits located in Zanjan, NW Iran. Understanding the tectonic events that can cause mineralization and hydrothermal alteration are significant factor in assessing the exploration potential of different structures. In this research, hydrothermal alteration such as Iron oxide, argillic, phyllic, and propylitic zones were determined by Spectral Angle Method (SAM) and also lineaments identified by high pass filters and hill-shade DEM techniques on Advanced Space borne Thermal Emission and Reflection Radiometer (ASTER) data. Field studies revealed most alteration and mineralization occurred in NE-SW fractures and control mineralization.展开更多
In view of the importance of mafic dyke swarms and their contribution to current scientific problems relating to South China,herein,we present the findings of studies on twenty–five representative mafic dykes croppin...In view of the importance of mafic dyke swarms and their contribution to current scientific problems relating to South China,herein,we present the findings of studies on twenty–five representative mafic dykes cropping out in Hunan Province and Guangxi Zhuang Autonomous Region,within the southern Wuling Mountain gravity lineament,China.These results include new zircon LA-ICP-MS U-Pb age,whole rock geochemical,Sr-Nd-Pb isotopic,and zircon Hf isotopic data for these dykes.The dykes formed between 131.5±1.2 and 121.6±1.1 Ma,and have typical doleritic textures.They fall into the alkaline and shoshonitic series,are enriched in light rare earth elements(LREE),some large ion lithophile elements(LILE;e.g.,Rb,Ba,and Sr),Th,U,and Pb,and are depleted in Nb,Ta,Hf,and Ti.Moreover,the dolerites have high initial 87 Sr/86 Sr ratios(0.7055–0.7057),negativeεNd(t)and zirconεHf(t)values(-14.8 to-11.9,-30.4 to-14.9),and relatively constant initial Pb isotopic ratios(that are EM1-like,16.77–16.94,15.43–15.47,and 36.84–36.92 for 206 Pb/204 Pb,207 Pb/204 Pb,and 208 Pb/204 Pb,respectively).These results indicate that the dykes were likely derived from magma generated through low-degree partial melting(1.0%–10%)of an EM1-like garnet–lherzolite mantle source.The parental magmas fractionated olivine,clinopyroxene,plagioclase,and Ti-bearing phases with negligible crustal contamination,during ascent and dyke emplacement.Several possible models have been proposed to explain the origin of Mesozoic magmatism along the Wuling Mountain gravity lineament.Herein we propose a reasonable model for the origin of these mafic dykes,involving the collision between the paleo-Pacific Plate and South China,which led to subsequent lithospheric extension and asthenosphere upwelling,resulting in partial melting the underlying mantle lithosphere in the Early Cretaceous,to form the parental magmas to the WMGL mafic dykes,as studied.展开更多
Northeastern Morocco is made up of several units belonging to the Alpine belt and its foreland. Miocene to plio-quaternary volcanic rocks with variable mineralogy and geochemistry dominate the geology of this region. ...Northeastern Morocco is made up of several units belonging to the Alpine belt and its foreland. Miocene to plio-quaternary volcanic rocks with variable mineralogy and geochemistry dominate the geology of this region. The presence of active faults in different directions explains the high tectonic instability and the high frequency of earthquakes. This study contributes to the effort of understanding the geothermal potential of the Northeast of Morocco. Heat source and permeability are both key factors in the geothermal process. Indeed, lineaments analysis constrains the structures and their directions and indicates severely faulted zones, which are the most promising areas for geothermal exploration. For this purpose, we used Landsat data combined with geological and structural maps available in this region. Different image processing techniques were applied including band ratio (6/2) and directional filters. To validate the results, we conducted a comparative study between linear structures, available geological data, and previous studies. Results of the automatic extraction method of lineaments from Landsat 8 OLI/TIRS indicate three main lineament systems: 1) a NE-SW system ranging from N40 to N70;2) an N-S system ranging from N10 to N45;3) an EW to WNW-ESE systems ranging from N80 to N120. Most of lineaments extracted are localized in Kebdana, Amejjaou, Nador and Melilla regions. Compared to previous studies, the NE-SW system is consistent with an extensive period (Tortonian to Pliocene);the NW-SE system is consistent with the last compressive episode (Pliocene);the N-S system is consistent with the first compressive period (Late/End Tortonian).展开更多
Groundwater is the most important source of water in the Halabja-Saidsadiq Basin. In this study, to generate a map of groundwater pollution vulnerability of the basin, the standard DRASTIC method has been applied. Due...Groundwater is the most important source of water in the Halabja-Saidsadiq Basin. In this study, to generate a map of groundwater pollution vulnerability of the basin, the standard DRASTIC method has been applied. Due to the close relation between lineament density and groundwater flow and yield, the lineament density map was applied to the standard DRASTIC model in order to ensure accuracy towards the consideration of the effects of potential vulnerability to contamination. A lineament map is extracted from Enhanced Thematic Mapper plus (ETM+) satellite imagery using different techniques in remote sensing and GIS. The lineament density map illustrates that only six classes of lineament density can be identified ranged from (0 - 2.4). The lineament density map was rated and weighted and then converted to lineament index map. This index map is an additional parameter which was added to the standard DRASTIC model so as to map the modi?ed DRASTIC vulnerability in HSB. The standard vulnerability map, classified the basin into four vulnerability index zones: very low (34%), low (13%), moderate (48%) and high (5%). While the modified model classified the area into four categories as well: very low (28.75%), low (14.31%), moderate (46.91%) and high (10.04%). The results demonstrate that there is no significant variation in the rate of vulnerability. Therefore, the nitrate concentration between two different seasons (dry and wet) was analyzed from (30) water wells, considerable variations in nitrate concentration from dry to wet seasons had been noted. Consequently, it confirmed that the HSB are capable to receive the contaminant because of suitability in terms of geological and hydrogeological conditions. Based on this verification, it could be claimed that the effect of lineament density is weak on the vulnerability system in HSB, because of its low density value.展开更多
Lineaments are often related to faults and lithologic boundaries and in some cases to geomorphic relief. They can be helpfully utilized by investigating active tectonics as preliminary data. In order to assess the dis...Lineaments are often related to faults and lithologic boundaries and in some cases to geomorphic relief. They can be helpfully utilized by investigating active tectonics as preliminary data. In order to assess the distribution and activity of the lineaments around the coastal area of the Korean Peninsula, we have interpreted lineaments using ASTER (Advanced Space borne Thermal Emission and Reflection Radiometer) images. The lineaments range from 2 km to 50 km long and show a dominant NNW-SSE trend. The lineament density along the eastern coast line of the Korean Peninsula is higher than the densities on the southern and western coast lines. The lineament rank is La to Le. However, La and Lb are not in sufficient abundance to have a high possibility to be active. In the Pocheon region, there are Quaternary volcanic activities, and hence there is a possibility of recent crustal movement in this area. We plan to recheck the presence and activity of ASTER lineaments by aerial photographs and field investigations in the future.展开更多
With the aim to produce a detailed structural map and then enhance the geological information of the south-western Cameroon, a field gravity study is carried out in the Kribi-Campo-Ma’an area (SW Cameroon). This stud...With the aim to produce a detailed structural map and then enhance the geological information of the south-western Cameroon, a field gravity study is carried out in the Kribi-Campo-Ma’an area (SW Cameroon). This study area is assumed to undergo pending active tectonics as witnessed by several earthquakes [1]. Besides, the area has been affected by some shears that gave rise to many major faults including the Kribi-Campo Fault (KCF). This N-S lineament is an active fault corresponding to the NW margin of the CC [2] [3] and related to the development of the Kribi-Campo basin. The gravity data analysis enables to highlight many deeply-seated structural features trending in the NE, NNE, N-S, NNW, NW and E-W directions in this region. The NW-SE trend is more strongly developed than the other identified trends and could have deeply affected the major NNE structure. The NNE-SSW to N-S fractures and faults which are local relays of the Kribi-Campo fault are related to the Kribi shear zone. The fairly good clustering observed on local maxima of the horizontal gradient magnitude enables to suggest that the contacts outlined have vertical to subvertical dips. However, a probable interpretation of these features is that they are vertical to subvertical faults which follow the aforementioned directions. The location of the study area in the gulf of Guinea suggests that it sustains tectonics related both to the equatorial and the south Atlantic oceans opening.展开更多
A family of geophysical lineaments have been identified in ~15,000 km^2 in central Kerala between9 30'N to 10 45'N and 76 00'E to 77°30′E,integrating geophysical data with geological and geomorpholog...A family of geophysical lineaments have been identified in ~15,000 km^2 in central Kerala between9 30'N to 10 45'N and 76 00'E to 77°30′E,integrating geophysical data with geological and geomorphological features. The characteristics of these lineaments in the magnetic and gravity fields and their derivatives have been analysed. The evolution of the lineaments has been traced to the temporal phases of global evolution of the region. A group of these faults have formed by reactivation of the deep-seated distensional fractures associated with and accompanying dyke emplacements during the episodic breakup of Gondwana at ~90 and 65 Ma under distinctive mantle thermal regimes. It is possible that reactivation of these distensional faults may have started during the cooling interval of time between the two distensions in the 90 and 65 Ma and post 65 Ma periods and later in the Cenozoic, when the lineaments were enlarged to their present dimension, possibly under the influence of forces that led to the uplift of the western Ghats. These may extend down to the crust-mantle interface. A cluster of youngergeophysical lineaments has been generated by reactivation along the weak planes of transformation of the charnockitic rocks of the Precambrian. They seem to have a strike-slip character. They are devoid of any dyke association and were formed on a cold crust. They may be confined to the upper-middle crust.They were generated in the high intensity intra-plate palaeo-stress fields of the triple forces arising from(1) the back-thrust from the Himalayan Collision;(2) the impact of epeirogenic forces and related isostatic uplift of the Western Ghats and(3) the flexural isostatic uplifts due to surface loads of late Mesozoic basaltic lavas and Cenozoic sedimentation in the coastal rifted basins in late Cenozoic, probably in the time span of 20 Ma to the present, when the palaeostress fields were most intense.展开更多
: The“ ring-morphostructures” (RM) are the object of this study. They are one of the most significant element of lineament’s structure and unknown for the majority of investigations. RM are numerous to lineament’...: The“ ring-morphostructures” (RM) are the object of this study. They are one of the most significant element of lineament’s structure and unknown for the majority of investigations. RM are numerous to lineament’s zone: they have different size (from 10-20km to 500-800km in diameter), structure, age, geological history and have been divided into several classes on the most important signs. They have a spatial-genetic connection Amur-Songhua-Huanghe lineament (ASHL) and had been developed simultaneously with it. The RM exerted an essential influence on the geologic-geomorphological structure, evolution and geodynamics of lineament. The main factor of evolution of lineament is a long geological process of extension of the earth’s crust which is a result of the expanding earth.展开更多
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 ...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.展开更多
The rocks of the Jos – Bukuru area in North Central Nigeria is characterized by negative and positive gravity residual anomalies ranging from –25 to +20 mGals. Lineaments were extracted from the gravity residual ano...The rocks of the Jos – Bukuru area in North Central Nigeria is characterized by negative and positive gravity residual anomalies ranging from –25 to +20 mGals. Lineaments were extracted from the gravity residual anomaly map for the purpose of assessing the groundwater resources in the area. The region is marked by more than one set of lineaments, each with its distinctive orientation and probably spacing. Lineaments shorter than 20 km in length are shallow structures suitable for this exercise because of their importance in groundwater recharge, transmission and discharge. In a bin size of 15oone major and one minimum striking directions between 000o and 030o were obtained. The major type lies between 000o and 015o, while the minimum one is oriented within the 015o and 030o direction. These directions correspond to the stress axis of the essentially north – south trending geological structures of Nigeria. Invasions of mineralizing fluids might had sealed some of the joints and other fractures, however where the open spaces are not sealed, weathering and erosion widen and deepened the joints paving routes for surface water flows and direct seepage into the underlying strata. On the lineament density and lineament intersection maps the closures suggest probable discontinuity of the aquifer units. On this basis of the lineament density and the lineament intersection results, the area was divided into three hydrogeological zones. Site 1 is considered most favourable for water well development, while site 3 may result in low yields or even in abortive water wells.展开更多
This work is to study earthquake precursors using lineament analysis of five MW3 earthquakes that occurred in 2018 on the territory of the Tashkent geodynamic polygon in Uzbekistan.The Landsat 8 satellite images were ...This work is to study earthquake precursors using lineament analysis of five MW3 earthquakes that occurred in 2018 on the territory of the Tashkent geodynamic polygon in Uzbekistan.The Landsat 8 satellite images were processed using the automated lineament detection method in the LEFA software.The processing steps included image preprocessing with graphic filters,edge detection using Canny’s algorithm,the definition of a vector of linear elements based on the probabilistic Hough transform and combining collinear linear elements into lineaments.The analysis of the cyclicity of precursors before and after earthquakes was based on the study of the distribution of the lineaments trend in the study area using rose diagrams and lineaments density maps.The results showed a change in the dynamics of the lineament structure.The statistical analysis of lineaments revealed that the number and orientation of lineaments changed significantly about 2-4 months before an earthquake,and after 2-3 months,the system gradually returned to its initial state.The rapid increase in lineaments density began almost 20 days before the event,reaching a maximum about 4 days before the earthquake,and its decrease began16 days after the earthquake.The main trends observed in the lineament map showed dominant trends in NS,EW,and the subdominant directions were in NW-SE,NE-SW,which coincided with main directions of the faults.展开更多
An earthquake called the MW7.2“El Mayor Cucapah”earthquake on April 4,2010 has been analyzed for seismic precursor.The changes in the lineament system concerning its pattern and time intervals were analyzed during t...An earthquake called the MW7.2“El Mayor Cucapah”earthquake on April 4,2010 has been analyzed for seismic precursor.The changes in the lineament system concerning its pattern and time intervals were analyzed during the earthquake preparation period and occurrence using the automated lineament detection method.The Landsat 5 TM images were processed using LESSA and ADALGEO software obtaining similar results.The statistical analysis revealed the stress accumulation due to plate interaction during earthquake formation.The study shows that the number of extracted lineaments changes rapidly about 23 months before the earthquake,and the systems return to the initial stage after 23 months.Most lineaments coincide with the extension of the San Andreas Fault as NW direction is the dominant trend.Thus,it can be concluded that the featural changes within the Rose diagram corresponding to the different strokes direction along with oriented elongation lines as disclosed in the present study using satellite images could be identified as a mid-term and/or short-term precursors of the earthquake.However,even though the dynamism of the El Mayor Cucapah earthquake is found in the extracted lineaments,it is possible to isolate more significant earthquakes even if new ones appear near the zone.Moreover,using two algorithms for lineament detection allows for the tectonics to corroborate the obtained lineaments and dynamism.展开更多
Based on digital elevation models SRTM03 and SRTM30_Plus (Shuttle Radar Topography Mission Survey) the technique for detecting major structural elements and elucidating details of the geologic structure including disc...Based on digital elevation models SRTM03 and SRTM30_Plus (Shuttle Radar Topography Mission Survey) the technique for detecting major structural elements and elucidating details of the geologic structure including discrimination of linear structures and texture features is elaborated. The computation of the modulus of the first derivative by the co- ordinate, i.展开更多
Gravity method is among the most applied geophysical methods in mineral and oil exploration. It may help to identify fault networks which are of interest for mineral exploration. Potential field data can give valuable...Gravity method is among the most applied geophysical methods in mineral and oil exploration. It may help to identify fault networks which are of interest for mineral exploration. Potential field data can give valuable information on the location of faults in the basement. These faults may have propagated into the overlying sedimentary rocks and influenced fluid flow and distribution of hydrocarbon traps and mineralization zones. A study was therefore conducted in south Cameroon with the aim of highlighting the different lineaments of the region, which were completely or partially hidden by the sedimentary cover. Different gravity data processing techniques including horizontal gradient coupled with upward continuation and Euler deconvolution were used. The application of these methods has mapped out a number of lineaments depicting gravity density discontinuities whose directions are NS, NE-SW, EW and NW-SE. The predominant direction for major lineaments is NE-SW. The major lineaments associated to the faults are: the Kribi-Edea faults, Ambam faults, Ebolowa-south of Yaounde faults;Bipindi-Yaounde faults;Pouma-Yaounde fault and the fault system which crosses the east, north, west of Monatele city. Euler solutions indicate depths up to18 km for the roof of the faults. The main results worked out from this study provide with new elements that allow the improvement of the knowledge on the structure of the study area. The structural map obtained shows major tectonic events that are responsible of the structural layout of the study zone. In addition, information related to the dip and depth of the various structures was also obtained. The map of lineaments is a useful tool for the planning of hydrogeological and/or petroleum investigations.展开更多
In this paper, the complexity in the spatial distribution of the lineaments was investigated from on remote sensing topographic (SRTM DEM) and multispectral (Landsat) data. Lineaments in equatorial Africa were chosen ...In this paper, the complexity in the spatial distribution of the lineaments was investigated from on remote sensing topographic (SRTM DEM) and multispectral (Landsat) data. Lineaments in equatorial Africa were chosen to apply the fractal analysis methodology. The good correlations of the obtained data with some geophysical data from the same area allow that the complexity in the spatial distribution of the lineaments can give qualitative information on the interior of the earth (or on other planets). This method can provide a bridge between classical geology and geophysics, and particularly powerful for studying large and inaccessible regions.展开更多
文摘The integration of remotely sensed data allowed the successful characterization of the mineral alteration zones of the Oudiane Elkharoub area in the Northeastern part of Reguibat Shield using image transformation techniques. As both chemical and geochemical analyses showed significant Au, Ag, Cu, Pb, Mn, Cr, Ni, Th and Y anomalies, it’s very interesting to apply the remote sensing and GIS in mineral resources mapping. The remote sensing is a direct adjunct to the field, lithologic and structural mapping, and more recently, GIS has played an important role in the study of mineralization areas. The integration of several evidential maps highlighted the plausible areas with high concentrations of chlorite, epidote, kaolinite, calcite, alunite, hematite, illite and sulfur among other key mineral alterations that reflect the intensity of hydrothermal effects and the probable sites of ore bodies. The methodological approach integrates geological information acquired from Aster and Landsat 8 OLI/TIRS (Operational Land Imager/Thermal InfraRed Sensor) images and a multi-criteria GIS analysis. The superimposition of various lineament and hydrothermal alteration maps and the consideration of precious and base metal indicators allowed the zoning of sites likely to contain mineral concentrations. Remote sensing becomes an important tool for locating mineral deposits in its own right, when the primary and secondary processes of mineralization result in the formation of spectral anomalies. Reconnaissance lithological mapping is usually the first step of mineral resource mapping. This is complimented with structural mapping, as mineral deposits usually occur along or adjacent to geologic structures, and alteration mapping, as mineral deposits are commonly associated with hydrothermal alteration of the surrounding rocks. Ground truthing and laboratory studies including XRD analysis were utilized to verify the results.
文摘Drainage responds rapidly to tectonic changes and thus it is a potential parameter for teetonogeomorphological analysis. Drainage network of Potwar is a good geological record of movement, displacements, regional uplifts and erosion of the tectonic units. This study focuses on utilizing drainage network extracted from Shuttle Radar Digital Elevation Data (SRTM-DEM) in order to constrain the structure of the Potwar Plateau. SWAN syncline divides Potwar into northern Potwar deformed zone (NPDZ) and southern Potwar platform zone (SPPZ). We extracted the drainage network from DEM and analyzed 112 streams using stream power law. Spatial distribution of concavity and steepness indices were used to prepare uplift rate map for the area. DEM was further utilized to extract lineaments to study the mutual relationship between lineaments and drainage patterns. We compared the local correlation between the extracted lineaments and drainage network of the area that gives us quantitative information and shows promising prospects. The streams in the NPDZ indicate high steepness values as compared to the streams in the SPPZ. The spatial distribution of geomorphic parameters distinctive deformation and uplift rates suggest the among eastern, central and western parts. The local correlation between drainage network and lineaments from DEM is strongly positive in the area within I km of radius.
文摘This paper presents a lineament detection method using multi-band remote sensing images. The main objective of this work is to design an automatic image processing tool for lineament mapping from Landsat-7 ETM + satellite data. Five procedures were involved: 1) The Principal Component Analysis;2) image enhancement using histogram equalization technique 3) directional Sobel filters of the original data;4) histogram segmentation and 5) binary image generation. The applied methodology was contributed in identifying several known large-scale faults in the Northeast of Tunisia. The statistical and spatial analyses of lineament map indicate a difference of morphological appearance of lineaments in the satellite image. Indeed, all the lineaments present a specific organization. Five groups were classified based on three orientations: NE-SW, E-W and NW-SE. The overlapping of lineament map with the geologic map confirms that these lineaments of diverse directions can be identified and recognized on the field as a fault. The identified lineaments were linked to a deep faults caused by tectonic movements in Tunisia. This study shows the performance of the satellite image processing in the analysis and mapping of the accidents in the northern Atlas.
文摘Sinai Peninsula has fascinating geologic setting and is displaying a diversity of structural lineaments that have greatly influenced the distribution of natural resources and hazards. Shaded relief images derived from SRTM-DEM mosaics were used for the identification, extraction, and mapping of these structural lineaments. Statistical parameters particularly, azimuth frequency, lineament intersection, lengths, and density distribution were analyzed using SPSS software. Two additional new statistical indices;Lineament Relative Abundance Index (LRAI) and Lineament Majority-Minority Index (LMMI) were applied. Moreover, the distribution of the different statistical parameters was illustrated as contour maps through GIS environment. Basically, two dominant clusters;NW-SE and NNE-SSW trends were detected. These trends are related to major fracture systems that are characterized by extensive mean lengths and high proportion values. Furthermore, the northern and central parts of Sinai Peninsula have lower density and intersection of structural lineaments that gradually increase towards the southern part. However, the northern part of Sinai displays wider areas of majority zones than the southern part. This could be attributed to the lower density of lineaments and little tendency for multiple lineament populations. The majority zones are usually associated with NE and NW-SE in the northern part of Sinai, whereas the majority zones are of less abundance in the central and southern parts of Sinai due to the multiple orientations of lineament populations which reduce the tendency for majority. Eventually, the results of the present work could be applicable in the different geologic and environmental aspects that are based on a good understanding of the genetic and spatial relationships of fracture systems. These aspects encompass geodynamics, exploration for mineralization and groundwater, in addition to the mitigation of natural hazards such as flush flooding and earthquakes.
文摘East Azarbaijan belongs to the Iranian plateau and is part of lesser Caucasus province. Studied area is located in west-central Alborz. The intrusion of oligocene bodies in various units causes the alteration and mineralization in northwest of Iran. The Hizejan-Sharafabad is one of this named mineralized zone. Granitoidicrocks with component of Granodiorite to alkali have been influenced by hydrothermal fluids. Fractures and faults are as weak zone in earth surface and hydrothermal fluids rise to surface by these geological structures. These solutions cause to alteration in host rocks. Alteration zones are important features for the exploration of deposits. The altered rocks have specific absorption in some spectral portion and ASTER sensor is able to identify the type of alteration. Remote sensing method is useful tool for discovering altered area. The purpose of this study is to appraise ASTER data for surveying altered minerals in Hizejan-Sharafabad area in the event of detecting the potential mineralized areas. In this research, False Color Composite (FCC), Band ratio, and color composite ratio techniques are applied on ASTER data and Silica, Argilic, and Propylitic alteration zones are detected. These alteration types and mineralized area are related to Hizejan–Sharafabad fault which is absent in the fault maps. ASAR image processing has been used for lineaments and faults identified by the aid of Directional and Canny Algorithm filters. The structural study focuses on fracture zones and their characteristics including strike, length, and relationship with alteration zones.
文摘The study area that is part of Tarom volcano-plutonic zone which host many hydrothermal base metal deposits located in Zanjan, NW Iran. Understanding the tectonic events that can cause mineralization and hydrothermal alteration are significant factor in assessing the exploration potential of different structures. In this research, hydrothermal alteration such as Iron oxide, argillic, phyllic, and propylitic zones were determined by Spectral Angle Method (SAM) and also lineaments identified by high pass filters and hill-shade DEM techniques on Advanced Space borne Thermal Emission and Reflection Radiometer (ASTER) data. Field studies revealed most alteration and mineralization occurred in NE-SW fractures and control mineralization.
基金supported by the National Natural Science Foundation of China(grant,41573022)。
文摘In view of the importance of mafic dyke swarms and their contribution to current scientific problems relating to South China,herein,we present the findings of studies on twenty–five representative mafic dykes cropping out in Hunan Province and Guangxi Zhuang Autonomous Region,within the southern Wuling Mountain gravity lineament,China.These results include new zircon LA-ICP-MS U-Pb age,whole rock geochemical,Sr-Nd-Pb isotopic,and zircon Hf isotopic data for these dykes.The dykes formed between 131.5±1.2 and 121.6±1.1 Ma,and have typical doleritic textures.They fall into the alkaline and shoshonitic series,are enriched in light rare earth elements(LREE),some large ion lithophile elements(LILE;e.g.,Rb,Ba,and Sr),Th,U,and Pb,and are depleted in Nb,Ta,Hf,and Ti.Moreover,the dolerites have high initial 87 Sr/86 Sr ratios(0.7055–0.7057),negativeεNd(t)and zirconεHf(t)values(-14.8 to-11.9,-30.4 to-14.9),and relatively constant initial Pb isotopic ratios(that are EM1-like,16.77–16.94,15.43–15.47,and 36.84–36.92 for 206 Pb/204 Pb,207 Pb/204 Pb,and 208 Pb/204 Pb,respectively).These results indicate that the dykes were likely derived from magma generated through low-degree partial melting(1.0%–10%)of an EM1-like garnet–lherzolite mantle source.The parental magmas fractionated olivine,clinopyroxene,plagioclase,and Ti-bearing phases with negligible crustal contamination,during ascent and dyke emplacement.Several possible models have been proposed to explain the origin of Mesozoic magmatism along the Wuling Mountain gravity lineament.Herein we propose a reasonable model for the origin of these mafic dykes,involving the collision between the paleo-Pacific Plate and South China,which led to subsequent lithospheric extension and asthenosphere upwelling,resulting in partial melting the underlying mantle lithosphere in the Early Cretaceous,to form the parental magmas to the WMGL mafic dykes,as studied.
文摘Northeastern Morocco is made up of several units belonging to the Alpine belt and its foreland. Miocene to plio-quaternary volcanic rocks with variable mineralogy and geochemistry dominate the geology of this region. The presence of active faults in different directions explains the high tectonic instability and the high frequency of earthquakes. This study contributes to the effort of understanding the geothermal potential of the Northeast of Morocco. Heat source and permeability are both key factors in the geothermal process. Indeed, lineaments analysis constrains the structures and their directions and indicates severely faulted zones, which are the most promising areas for geothermal exploration. For this purpose, we used Landsat data combined with geological and structural maps available in this region. Different image processing techniques were applied including band ratio (6/2) and directional filters. To validate the results, we conducted a comparative study between linear structures, available geological data, and previous studies. Results of the automatic extraction method of lineaments from Landsat 8 OLI/TIRS indicate three main lineament systems: 1) a NE-SW system ranging from N40 to N70;2) an N-S system ranging from N10 to N45;3) an EW to WNW-ESE systems ranging from N80 to N120. Most of lineaments extracted are localized in Kebdana, Amejjaou, Nador and Melilla regions. Compared to previous studies, the NE-SW system is consistent with an extensive period (Tortonian to Pliocene);the NW-SE system is consistent with the last compressive episode (Pliocene);the N-S system is consistent with the first compressive period (Late/End Tortonian).
文摘Groundwater is the most important source of water in the Halabja-Saidsadiq Basin. In this study, to generate a map of groundwater pollution vulnerability of the basin, the standard DRASTIC method has been applied. Due to the close relation between lineament density and groundwater flow and yield, the lineament density map was applied to the standard DRASTIC model in order to ensure accuracy towards the consideration of the effects of potential vulnerability to contamination. A lineament map is extracted from Enhanced Thematic Mapper plus (ETM+) satellite imagery using different techniques in remote sensing and GIS. The lineament density map illustrates that only six classes of lineament density can be identified ranged from (0 - 2.4). The lineament density map was rated and weighted and then converted to lineament index map. This index map is an additional parameter which was added to the standard DRASTIC model so as to map the modi?ed DRASTIC vulnerability in HSB. The standard vulnerability map, classified the basin into four vulnerability index zones: very low (34%), low (13%), moderate (48%) and high (5%). While the modified model classified the area into four categories as well: very low (28.75%), low (14.31%), moderate (46.91%) and high (10.04%). The results demonstrate that there is no significant variation in the rate of vulnerability. Therefore, the nitrate concentration between two different seasons (dry and wet) was analyzed from (30) water wells, considerable variations in nitrate concentration from dry to wet seasons had been noted. Consequently, it confirmed that the HSB are capable to receive the contaminant because of suitability in terms of geological and hydrogeological conditions. Based on this verification, it could be claimed that the effect of lineament density is weak on the vulnerability system in HSB, because of its low density value.
文摘Lineaments are often related to faults and lithologic boundaries and in some cases to geomorphic relief. They can be helpfully utilized by investigating active tectonics as preliminary data. In order to assess the distribution and activity of the lineaments around the coastal area of the Korean Peninsula, we have interpreted lineaments using ASTER (Advanced Space borne Thermal Emission and Reflection Radiometer) images. The lineaments range from 2 km to 50 km long and show a dominant NNW-SSE trend. The lineament density along the eastern coast line of the Korean Peninsula is higher than the densities on the southern and western coast lines. The lineament rank is La to Le. However, La and Lb are not in sufficient abundance to have a high possibility to be active. In the Pocheon region, there are Quaternary volcanic activities, and hence there is a possibility of recent crustal movement in this area. We plan to recheck the presence and activity of ASTER lineaments by aerial photographs and field investigations in the future.
文摘With the aim to produce a detailed structural map and then enhance the geological information of the south-western Cameroon, a field gravity study is carried out in the Kribi-Campo-Ma’an area (SW Cameroon). This study area is assumed to undergo pending active tectonics as witnessed by several earthquakes [1]. Besides, the area has been affected by some shears that gave rise to many major faults including the Kribi-Campo Fault (KCF). This N-S lineament is an active fault corresponding to the NW margin of the CC [2] [3] and related to the development of the Kribi-Campo basin. The gravity data analysis enables to highlight many deeply-seated structural features trending in the NE, NNE, N-S, NNW, NW and E-W directions in this region. The NW-SE trend is more strongly developed than the other identified trends and could have deeply affected the major NNE structure. The NNE-SSW to N-S fractures and faults which are local relays of the Kribi-Campo fault are related to the Kribi shear zone. The fairly good clustering observed on local maxima of the horizontal gradient magnitude enables to suggest that the contacts outlined have vertical to subvertical dips. However, a probable interpretation of these features is that they are vertical to subvertical faults which follow the aforementioned directions. The location of the study area in the gulf of Guinea suggests that it sustains tectonics related both to the equatorial and the south Atlantic oceans opening.
文摘A family of geophysical lineaments have been identified in ~15,000 km^2 in central Kerala between9 30'N to 10 45'N and 76 00'E to 77°30′E,integrating geophysical data with geological and geomorphological features. The characteristics of these lineaments in the magnetic and gravity fields and their derivatives have been analysed. The evolution of the lineaments has been traced to the temporal phases of global evolution of the region. A group of these faults have formed by reactivation of the deep-seated distensional fractures associated with and accompanying dyke emplacements during the episodic breakup of Gondwana at ~90 and 65 Ma under distinctive mantle thermal regimes. It is possible that reactivation of these distensional faults may have started during the cooling interval of time between the two distensions in the 90 and 65 Ma and post 65 Ma periods and later in the Cenozoic, when the lineaments were enlarged to their present dimension, possibly under the influence of forces that led to the uplift of the western Ghats. These may extend down to the crust-mantle interface. A cluster of youngergeophysical lineaments has been generated by reactivation along the weak planes of transformation of the charnockitic rocks of the Precambrian. They seem to have a strike-slip character. They are devoid of any dyke association and were formed on a cold crust. They may be confined to the upper-middle crust.They were generated in the high intensity intra-plate palaeo-stress fields of the triple forces arising from(1) the back-thrust from the Himalayan Collision;(2) the impact of epeirogenic forces and related isostatic uplift of the Western Ghats and(3) the flexural isostatic uplifts due to surface loads of late Mesozoic basaltic lavas and Cenozoic sedimentation in the coastal rifted basins in late Cenozoic, probably in the time span of 20 Ma to the present, when the palaeostress fields were most intense.
基金Supported by the National Natural Science Foundation of China! (No.49471013)Changchun Jingyuetan Remote Sensing Test Site, t
文摘: The“ ring-morphostructures” (RM) are the object of this study. They are one of the most significant element of lineament’s structure and unknown for the majority of investigations. RM are numerous to lineament’s zone: they have different size (from 10-20km to 500-800km in diameter), structure, age, geological history and have been divided into several classes on the most important signs. They have a spatial-genetic connection Amur-Songhua-Huanghe lineament (ASHL) and had been developed simultaneously with it. The RM exerted an essential influence on the geologic-geomorphological structure, evolution and geodynamics of lineament. The main factor of evolution of lineament is a long geological process of extension of the earth’s crust which is a result of the expanding earth.
文摘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.
文摘The rocks of the Jos – Bukuru area in North Central Nigeria is characterized by negative and positive gravity residual anomalies ranging from –25 to +20 mGals. Lineaments were extracted from the gravity residual anomaly map for the purpose of assessing the groundwater resources in the area. The region is marked by more than one set of lineaments, each with its distinctive orientation and probably spacing. Lineaments shorter than 20 km in length are shallow structures suitable for this exercise because of their importance in groundwater recharge, transmission and discharge. In a bin size of 15oone major and one minimum striking directions between 000o and 030o were obtained. The major type lies between 000o and 015o, while the minimum one is oriented within the 015o and 030o direction. These directions correspond to the stress axis of the essentially north – south trending geological structures of Nigeria. Invasions of mineralizing fluids might had sealed some of the joints and other fractures, however where the open spaces are not sealed, weathering and erosion widen and deepened the joints paving routes for surface water flows and direct seepage into the underlying strata. On the lineament density and lineament intersection maps the closures suggest probable discontinuity of the aquifer units. On this basis of the lineament density and the lineament intersection results, the area was divided into three hydrogeological zones. Site 1 is considered most favourable for water well development, while site 3 may result in low yields or even in abortive water wells.
基金the scientific and applied project FA-A5-F014 of the Astronomical Institute of Uzbekistan with the financial support got from the Academy of Sciences of the Republic of Uzbekistan。
文摘This work is to study earthquake precursors using lineament analysis of five MW3 earthquakes that occurred in 2018 on the territory of the Tashkent geodynamic polygon in Uzbekistan.The Landsat 8 satellite images were processed using the automated lineament detection method in the LEFA software.The processing steps included image preprocessing with graphic filters,edge detection using Canny’s algorithm,the definition of a vector of linear elements based on the probabilistic Hough transform and combining collinear linear elements into lineaments.The analysis of the cyclicity of precursors before and after earthquakes was based on the study of the distribution of the lineaments trend in the study area using rose diagrams and lineaments density maps.The results showed a change in the dynamics of the lineament structure.The statistical analysis of lineaments revealed that the number and orientation of lineaments changed significantly about 2-4 months before an earthquake,and after 2-3 months,the system gradually returned to its initial state.The rapid increase in lineaments density began almost 20 days before the event,reaching a maximum about 4 days before the earthquake,and its decrease began16 days after the earthquake.The main trends observed in the lineament map showed dominant trends in NS,EW,and the subdominant directions were in NW-SE,NE-SW,which coincided with main directions of the faults.
基金funded by CONACyT(Consejo Nacional de Ciencia y Tecnología)Autonomous University of Sinaloa,in Mexico,grant number CVU:429125。
文摘An earthquake called the MW7.2“El Mayor Cucapah”earthquake on April 4,2010 has been analyzed for seismic precursor.The changes in the lineament system concerning its pattern and time intervals were analyzed during the earthquake preparation period and occurrence using the automated lineament detection method.The Landsat 5 TM images were processed using LESSA and ADALGEO software obtaining similar results.The statistical analysis revealed the stress accumulation due to plate interaction during earthquake formation.The study shows that the number of extracted lineaments changes rapidly about 23 months before the earthquake,and the systems return to the initial stage after 23 months.Most lineaments coincide with the extension of the San Andreas Fault as NW direction is the dominant trend.Thus,it can be concluded that the featural changes within the Rose diagram corresponding to the different strokes direction along with oriented elongation lines as disclosed in the present study using satellite images could be identified as a mid-term and/or short-term precursors of the earthquake.However,even though the dynamism of the El Mayor Cucapah earthquake is found in the extracted lineaments,it is possible to isolate more significant earthquakes even if new ones appear near the zone.Moreover,using two algorithms for lineament detection allows for the tectonics to corroborate the obtained lineaments and dynamism.
文摘Based on digital elevation models SRTM03 and SRTM30_Plus (Shuttle Radar Topography Mission Survey) the technique for detecting major structural elements and elucidating details of the geologic structure including discrimination of linear structures and texture features is elaborated. The computation of the modulus of the first derivative by the co- ordinate, i.
文摘Gravity method is among the most applied geophysical methods in mineral and oil exploration. It may help to identify fault networks which are of interest for mineral exploration. Potential field data can give valuable information on the location of faults in the basement. These faults may have propagated into the overlying sedimentary rocks and influenced fluid flow and distribution of hydrocarbon traps and mineralization zones. A study was therefore conducted in south Cameroon with the aim of highlighting the different lineaments of the region, which were completely or partially hidden by the sedimentary cover. Different gravity data processing techniques including horizontal gradient coupled with upward continuation and Euler deconvolution were used. The application of these methods has mapped out a number of lineaments depicting gravity density discontinuities whose directions are NS, NE-SW, EW and NW-SE. The predominant direction for major lineaments is NE-SW. The major lineaments associated to the faults are: the Kribi-Edea faults, Ambam faults, Ebolowa-south of Yaounde faults;Bipindi-Yaounde faults;Pouma-Yaounde fault and the fault system which crosses the east, north, west of Monatele city. Euler solutions indicate depths up to18 km for the roof of the faults. The main results worked out from this study provide with new elements that allow the improvement of the knowledge on the structure of the study area. The structural map obtained shows major tectonic events that are responsible of the structural layout of the study zone. In addition, information related to the dip and depth of the various structures was also obtained. The map of lineaments is a useful tool for the planning of hydrogeological and/or petroleum investigations.
文摘In this paper, the complexity in the spatial distribution of the lineaments was investigated from on remote sensing topographic (SRTM DEM) and multispectral (Landsat) data. Lineaments in equatorial Africa were chosen to apply the fractal analysis methodology. The good correlations of the obtained data with some geophysical data from the same area allow that the complexity in the spatial distribution of the lineaments can give qualitative information on the interior of the earth (or on other planets). This method can provide a bridge between classical geology and geophysics, and particularly powerful for studying large and inaccessible regions.