The study area comprises the southeastern part of the Western Desert of Egypt. The aims of the present study are to delineate the major surface and subsurface structures and to evaluate tectonic ...framework of the study area. Surface studies of the present work are based mainly on data from two different types of remote sensing systems: 15 cloud-free Landsat Enhanced Thematic Mapper Plus (ETM+) images and Shuttle Radar Topography Mission (SRTM) DEM data. The remote sensing data were used to recognize and extract geological lineaments by calculating and interpreting DEM derivatives, including shaded relief maps, slope maps, and traverse profiles. A Bouguer anomaly map (scale 1:500,000) was used to delineate a detailed picture of the subsurface structure in the study area. The analysis of surface data, including SRTM DEM and ETM+, was combined with subsurface data, including Bouguer anomaly map, and gave new insight into the tectonic and structure patterns of the study area.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We used an integrated approach to constrain the geological structure of the Jifara Plain in northwest Libya. The analysis of surface data, including a digital elevation model (DEM), Landsat Enhanced ...Thematic Mapper Plus images, and geologic maps, was combined with subsurface data, including well logs and magnetic data. The DEM data were used for the identification of geological lineaments in the study area. The interpretation and analysis of the lineaments indicate that the Jifara Plain is controlled by three main fault systems, trending northwest-southeast, east-west, and northeast-southwest. The three trends represent the remnants of reactivated structures that formed under the stress regimes generated during the tectonic evolution of North Africa. The magnetic data reveal three northwest- and northeast-trending sedimentary basins in the study area. The depth of the basement inside the main basin ranges from 1 to 5 km. The results indicate that the Jifara Basin is shallower than the surrounding basins. The integration of the results reflects different periods of tectonic activity in the Jifara Plain and the adjacent Jabal Nafusah.
Problems Statement and Purpose. Libya is the fourth-largest country in Africa and the seventeenth-largest country in the world with area of 1,759,540 sq. km. Most of Libya is located in the Sahara ...Desert and known for being the driest and most remote regions with limited accessibility. In the 1970s, the Industrial Research Center in Libya began to create geological maps of all Libyan lands derived from analog (hard-copy) aerial photographs and geological field trips to some accessible places. Recently, remote sensing and data integration techniques using GIS are crucial to geological survey and mapping, which provides a useful tool for studying and investigating the geology of remote regions without having to physically access them. The purpose of this study is mapping lithological unites and structural lineaments in the region of Abu Ghaylan - Kiklah - Tighrinna, northwest Libya, using integrated remote sensing data and spatial analysis.
Data and Methods. Enhanced Thematic Mapper Plus (ETM+), Satellite Pour l'Observation de la Terre (SPOT 5), European Remote-Sensing Satellite-2 (ERS-2) Synthetic Aperture Radar (SAR) C-band, Digital Elevation Model (DEM), geologic maps, and aeromagnetic data were used to map and analyze the lithological and structural lineaments in the study area. Various fused images and IHS transformations were tested for lithological units recognizing. On the basis of spectral characteristics and topographic forms, lithological and structural lineaments were recognized and mapped. The extracted rasters and vectors data were integrated using remote sensing and GIS data integration techniques.
Ground Truthing. The purpose of the ground truthing was to validate the DEM-based structural mapping and identify any landslides, streams, or valleys that may appear as edges in the DEM data. Also, determining the locations of the artificial lines, that appears in the processed images as geological lineaments and edges.
Results and Discussion. The results indicate that remote sensing data were very useful in distinguishing between various rock units and recognizing geological lineaments in the study area. The generated lithologic map shows fifteen geological formations with apparent and accurate boundaries. The results exposed new geological lineaments in the study area. The direction of the extracted geological lineaments is dominantly NW-SE. The magnetic data reveal the boundary of sedimentary basin in the study area. The basement's depth within the basin varies from 122 meters to 4.5 kilometers. The extracted geological lineaments were analyzed and interpreted to provide more information about the main structural trends affecting the study area. The methods used in this study for remote sensing image analysis and field geological surveys can be used successfully in similar regions of Libya.
In this study, satellite imagery was used for structural and alteration mapping in the Nholi area, central Tanzania. Structural mapping was carried out by processing and interpreting SRTM-DEM data ...using remote sensing and GIS techniques. Various band ratios and the Relative Absorption Band Depth (RBD) method of ASTER image were used to delineate hydrothermal alteration zones. The orientation analysis of the extracted lineaments indicates that the study area is controlled by five structural trends: NE–SW, WNW–ESE, N–S, E–W and NW–SE. The VNIR and SWIR bands of ASTER data were effective in delineating hydrothermal alteration mineral zones associated with gold mineralization. The spatial distribution of hydrothermal alteration zones was verified by field survey, microscopic studies and XRD analysis. Furthermore, the extension of alteration zones around the known gold deposit together with lineaments has led to the identification of new potential areas. Data integration shows a positive correlation between the extracted lineaments and hydrothermal alteration zones, which may indicate that the mineralization in the study area is structurally controlled. Moreover, the microscopic study of sulphide minerals revealed both syn- and post-shearing characteristics.
Problems Statement and Purpose. Northern Tanzania Volcanic terrain has been a subject of evaluation for geothermal potential in the last four decades. The region is characterized by Neogene to Recent ...volcanic and tectonic activities. This preliminary study based on remote sensing, water chemistry, gravity data, geological structures and volcanic centers distribution reports the geothermal manifestations identified and discusses the implications on geothermal fluid pathways. Oxygen-hydrogen isotope data from water samples indicate that there were involved in the hydrothermal system. Tectono-Volcanic Structures. The Northern Tanzania Divergence (NTD) area characterized by Neogene to Recent volcanic and tectonic activities. Recent volcanic and tectonic activities are ash cone and lava dome eruption at the floor of Meru crater a century ago, dyke intrusion and volcanic eruption south of Gelai volcano, and Oldoinyo-Lengai volcano, respectively. Fumarolic activities and hot springs are dominant in a relatively young volcanic area to the north-eastern and northern part of the NTD. Data and Methods. Shuttle Radar Topography Mission (SRTM), Landsat 8 Operational Land Imager (OLI) image, water isotope analysis and gravity data were used to extract and analyze the surface and subsurface geological lineaments and map the hydrothermal alteration zones in the study area. The hydrothermal alteration is used to evaluate and identify the permeable structures. Analysis and interpretation of the length and trends of extracted lineaments were used to investigate the tectonic evolution. Geological map of a study area was digitized from the existing geological maps and the age of rocks to delineate volcanic activity and associated lineaments based on the age of the lithological domain. Digital image processing was applied to enhance the visual interpretation. Gravity data were used to give insight into the subsurface structure in the study area. Results and Discussion. The higher δ 18O values and large deviation from meteoric water lines suggest that is due to the interaction of fluids with host rocks at elevated temperatures. These are consistent with open structures that act as conduits for fluid flow. The potential field gravity data reveal a basin-like structure trending in the NNW direction. The gravity data show that the basement units gradually deepen towards the central part and that it is controlled by two main fault systems that trend N-S and NW-SE respectively. The gravity data presented here provides new constraints on the tectonic evolution and geothermal resources of the study area.
In this study, we successfully integrated geological data, potential field data, and remote sensing data with the aim of investigating and improving our knowledge of the structural setting of the ...Eljufra area, northwestern Libya. SPOT-5 panchromatic band and digital elevation models (DEM) were used to construct surface shaded maps, and gravity and aeromagnetic surveys were used to provide information on subsurface structures and the nature of intrusive bodies. The results revealed that the prevailing trend of lineaments is NNW-SSE and NNE-SSW. A Bouguer anomaly map revealed that horst and graben blocks occur inside the large graben. An analytic signal method was applied to the aeromagnetic data to estimate locations and the minimum depths to the contact. A comparison of gravity and magnetic data provided information on hydrothermally altered basalt and sediment density. An anticlinal structure was detected in the western part of the study area. The effects of faults on basalt rocks indicated geological time for volcanic activity.
This study evaluates the use of image processing techniques and methodologies of digital integration of multi-disciplinary geoscientific data to reduce the ambiguity in geological interpretations in ...different geological environments in Libya. To realize this objective, three areas were selected for this study; Eljufra, an arid environment; the mountainous environment Tarhunah; and the Jifara Plain, a coastal plain environment. Two types of remote sensing data were used in this study: Landsat Enhanced Thematic Mapper Plus (ETM+) and European Remote Sensing Satellite. The digital elevation model extracted from Shuttle Radar Topography Mission and digital topographic maps scale 1:50,000 were used for remote sensing interpretation. GIS and remote sensing-based methods were used to process and integrate all raster and vector layers data. This study offered dramatic benefits for geological interpretations and provided new insights into the efficiency of image processing methods in different geological environments.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Results of geothermal studies carried out at 149 onshore oil wells have been used in evaluation of temperature gradient and heat flow values of the eastern shore of the Gulf of Suez. The ...investigations included temperature logs in boreholes, calculation of amplitude temperature, geothermal gradients and heat flow. The results obtained indicate that geothermal gradient values are in the ranges of 0.02–0.044°C/m and regionally averaged mean heat flow values are found to fall in the interval of 45–120mW/m2. Temperature gradients and heat flow values change from low values eastward to high values toward the axial of Gulf of Suez rift. The result of this research work has been highly successful in identifying new geothermal resources eastward of the Gulf of Suez. Additionally, this study shows that the areas with relatively higher temperature gradients have lower oil window, mature earlier, than those with low gradient values. Thus, high temperature gradients cause to expedite the formation of oil at relatively shallow depths and narrow oil windows. On the other hand, low temperature gradient makes the oil window to be quite broad when locate at high depths.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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