Trending Lineaments Research Articles

Tectonic reevaluation of West Cameroon domain: Insights from high-resolution gravity models and advanced edge detection methods

The West Cameroon region, characterized by a diverse geomorphology of highlands and plains resulting from tectonic processes across different geological ages, has been extensively explored for natural resources. Recognizing the significance of its tectonic and magmatic features associated with seismic and volcanic activity, this study focuses on geodynamic investigations of the Cameroon Volcanic Line (CVL). Despite previous efforts, detailed structural geophysical studies of the West Cameroon domain have proven inconclusive, prompting a comprehensive structural reinterpretation. Utilizing the high-resolution SGG-UGM-2 satellite gravity model and innovative processing techniques, including the horizontal gradient of a modified tilt (HGSTDR), the balanced horizontal gradient (BHG), the tilt of the horizontal gradient (TAHG), the improvised horizontal gradient tilt angle (impTAHG), and the Tilt Depth method, our research aims to enhance the interpretational quality of tectonic lineaments. By separating regional and residual anomalies in the Bouguer gravity map and applying a combination of filters to delineate geological units, the BHG filter emerges as a robust tool that highlights subsurface edges without generating false features. This approach unveils previously undetected NNW-SSE-oriented lineaments, confirming the presence of deep fractures and faults in Bafoussam, Nkongsamba, and along the Benue Trough, corroborated by newly discovered NNW-SSW trending lineaments. The study suggests that the region’s topography is overcompensated by deep mountain roots and compressive tectonism. Digitizing the BHG filter produces a structural map, revealing predominant NE trends in identified geological margins, including NNE-SSW, N-S, NW-SE, E-W, and NE-SW directions. Geological contacts between granite and high-grade gneiss are indicated by NNW-SSE and NNE-SSW trending lineaments along the Benue Trough. These results contribute significantly to the understanding of the tectonic setting of the West Cameroon Domain.

Tectonics of Cauvery basin (India) in onshore and offshore portions

Morphometric studies coupled with geophysical investigations from petroliferous basins provide valuable information about tectonics of the regions. We deduce six morphologic parameters from the River Cauvery's designated (sub)watersheds and perform dendrogram clustering analysis. The main channels of the (sub)watersheds showcase steeper gradient and meandering nature with less concavity. On the other hand, the distributaries portray lesser gradient and straight nature with greater concavity. From the offshore region of the Cauvery basin, we perform gravity modeling. The results show variations in gravity values from low to high, -150 to 50 mGal probably because of the basement ridge-depression features. This anomaly orientation indicates the extension of the sub-basin in the region. A strong NE-SW gravity trend possibly suggests a high-density plug at mid-crust. The low gravity values near the Vedaranyam region indicate low-density rocks within the basement. Places of high gravity anomaly show a decrease in bathymetry depth and vice versa. This indicates isostatic compensation of the Moho geometry, possibly due to crustal thinning in the offshore areas. Isostatic regional gravity fields are manifested by Moho relief and can have implications on the lithospheric mechanical strengths. Bathymetric studies indicate multi-directional slopes. Relatively flat areas can indicate depocenters. E-W trending lineaments mapped on the Precambrian basement from a portion of the study area is presumably a manifestation of Cauvery Shear zone, which also persists in the offshore region.

Morphometry and active tectonics of the Konkan coast, western India

The Indian western coast is petroliferous drawing attention from academicians and industrial experts. In this work, geomorphic indices have been calculated to decode neotectonics of the Konkan onshore region on India’s west coast. Earthquake and Bouguer anomaly data have been used along with the present-day stress data from the World Stress Map project. Gravity modeling was performed in order to gain seismotectonic insights. The b-values were determined using Z-MAP 7.1 (2021). Morphometric analysis at both linear and spatial scales were performed using the digital elevation model from the data derived from the Shuttle Radar Topography Mission, analysed with ArcGIS 10.3 (2014) software. Maps depicting slopes, aspects, and reliefs were created. NW-SE trending lineaments in the Konkan plain guided the major stream courses. Two of the five watersheds, watersheds 4 and 5, reveal high tectonic activity, are landslide-prone and host hot springs. Interestingly, watersheds 4 and 5 show high b-values (except near the rivers’ sources), low Bouguer anomalies, and higher Hypsometric integral values (0.18523 and 0.16698) than the other watersheds. A low b-value in watershed 3 indicates stress accumulation. Over a larger area, the gravity trend varies from ∼ -80 to 30 mGal. The lineaments diagram deduced from the first vertical derivative technique shows that the structural fabrics mostly trend ∼ NW-SE at the west of the Western Ghat Escarpment (WGE) while it is NE-SW at the east. The tilt derivative ratio technique reveals a major NE-SW trend to the west of the WGE and an E-W trend to the east. Structural interpretations based on drill-cores around Koyna combined with geophysical studies for deep crust will be required are required for a better understanding of the blind (active) structures in the region.

Hydrogeological mapping of fracture networks using earth observation data to improve rainfall–runoff modeling in arid mountains, Saudi Arabia

Abstract Rainfall–runoff modeling is essential for the hydrological analysis of basins; however, the traditional modeling approach does not incorporate geological features such as fractures and fissures in the modeling task. These features are significant in the water loss during a rainstorm, which should be incorporated to obtain realistic rainfall–runoff results. A novel approach is presented here in to quantify the geological features and link them to the curve number (CN) method. The proposed methodology has not been applied in the literature. This approach is validated on five gauged basins, namely, Yiba, Al Lith, Liyya, Habawnah, and Tabalah, in the southwest part of Saudi Arabia. Four major stages are conducted. The first stage is the extraction of the geological lineaments using remote sensing and geographical information system technology; the second stage is estimating CN from rainfall–runoff data; the third stage is developing a relationship between CN and lineament density (LD); and the final stage is evaluating the developed equations on hydrological response. The least-squares method is employed to minimize the difference between observed and predicted runoff and determine the optimum range of CN. The research provides a comprehensive understanding of hydrological processes in fractured geologic systems and explores the influence of fractures on curve number. This study identifies two major lineament trends aligned with the Arabian trend direction, namely, north-northwest (NNW)–south-southeast (SSE) and north-northeast (NNE)–south-southwest (SSW). Furthermore, a moderate inverse correlation is established between LD and CN, highlighting the significance of geologic fractures on the hydrological response. The findings of this study provide insight into how the geological fissures in the mountainous region affected the rainfall–runoff response that leads to a low value of CN due to the water loss in the fissures and faults. As a result, this study clearly demonstrates the importance of the geological structures on rainfall–runoff responses.

A geospatial approach to delineate lineaments on the granite gneissic terrain of Mpwapwa district, Dodoma, central Tanzania

The study sought to utilise Geographic Information Systems (GIS), Remote Sensing, and a blend of manual and automatic techniques to delineate and analyse the spatial distribution and orientation of lineaments within the terrain of Mpwapwa District. The study employed various techniques, including the Optimum Index Factor (OIF), Band Combination, Principal Component Analysis (PCA), and Directional Filtering on the Landsat 8 imagery, and Hill Shading technique was used on Shuttle Radar Topography Mission Digital Elevation Model (SRTM DEM). These techniques were employed in the processing steps for both manual and automatic lineament extraction, utilizing various software tools. Lineament control and validation were executed using digitized geological maps, topographical maps, and Google Earth images.The results revealed lineaments with a total length of 2060.6 km, non-uniformly distributed and predominantly present in hard rock lithologies, such as migmatitic granite, migmatitic biotite gneiss, biotite gneiss, granitoid gneiss, and porphyroblastic gneiss. The findings further indicate that NE-SW and NW-SE are the dominant lineament trends. Additionally, the study revealed that areas with medium, high, and very high lineament density and intersection are primarily located in the southwest and northeast parts of the Mpwapwa District. Meanwhile, regions with low lineament density are spread through the entire district.In this study, GIS and remote sensing emerged as valuable tools for identifying and mapping lineaments within a challenging hydrogeological setting. Findings from this study will serve as a foundational framework for subsequent geological and hydrogeological investigations in the area of study.

Morphometric indices assessment: Implications for active tectonics in the upper Narmada Basin, central India

During the Palaeoproterozoic era, the Northern and Southern cratonic blocks of the Indian Plate came together and amalgamated. Farther, facilitated by the East-West trending central Tectonic Suture Zone, characterized by the Son-Narmada Fault/Lineament (SNF/L) and Central Shear (CIS) Zone, has long intrigued researchers due to its implications for active tectonics, particularly in the Narmada basin. In this study, we employ geomorphic and morphotectonic indices to elucidate the neotectonic activity in the Upper Narmada basin (UNB) of central India. Utilizing SRTM-DEM data, we analyze morphometric and morphotectonic parameters to shed light on the development of drainage patterns and active tectonics within the basin. Our findings reveal a pronounced influence of tectonics on basin evolution, as evidenced by high bifurcation ratios indicative of intense tectonic activity and elevated ruggedness values suggestive of heightened erosion susceptibility. The predominant ENE-WSW orientation of the Son Narmada South Fault (SNSF) and Son Narmada North Fault (SNNF), aligned with major lineament trends, exerts control over the Narmada River drainage network. Additionally, the high value (<50) of the asymmetric factor reveals the significant tectonic influence on the Upper Narmada basin, while the transverse asymmetric factor and stream length index values further corroborate the basin's susceptibility to active tectonics. Notably, the abrupt elevation changes (200–600 m asl) reflected by Dhuandhar, Kapildhara and other falls along the course of Narmada provide compelling evidence of neotectonic activity. Thus, we assert that morphotectonic analyses employing Digital Elevation Maps, satellite imagery, and SRTM-DEM data represent an efficacious approach for investigating complex basin morphotectonics.

Litho-structural interpretation of aeromagnetic anomalies reveals potential for mineral exploration in Tizi n'Test Region, Western High Atlas, Morocco

This study interprets aeromagnetic data from the Tizi n'Test area in the High Atlas massif of Morocco, aiming to gain insights into its litho-structural architecture and implications for mineral exploration and mining. We employed six different analytical techniques to the residual magnetic field data, including reduction to the pole (RTP), upward continuation, total horizontal derivative, Tilt angle, Centre for Exploration Targeting (CET) analysis, and Euler deconvolution. Our analyses differentiated the study area into three magnetic domains: the eastern Ouzellarh block, characterized by positive anomalies, a central domain characterized by a negative magnetic signature demarcating the transitional zone between the Anti-Atlas and the High Atlas separated by the Ouchden fault: and the western domain, represented by the Tichka massif. The application of total horizontal derivative, tilt angle, and a combination of filters in ternary image formats (Tilt angle, upward continuation 1000 + Tilt angle and upward continuation 3000 + Tilt angle) revealed both known and previously unidentified geological lineaments, mapping structural complexity across various orientations (NE–SW, NNE–SSE, E–W, NW–SE, and N–S). The CET grid analysis method unveiled the structural complexity, highlighting the geodynamic evolution of the region. Particularly, the Ouchden fault delineates a magnetic domain divide between the ancient High Atlas and the Ouzellarh block (Anti-Atlas). Furthermore, Euler deconvolution indicated magnetic source depths ranging from 52 m in the western domain of the Tichka massif to 6560 m in the Ouzellarh block. A comprehensive structural scheme, classified by C-A fractal analysis, identified zones favourable for exploration and mining, particularly along the Ouchden fault, Tizi n'Test, NE-SW trending lineaments in the northwestern domain, as well as along the Tichka granite’s margin.

INNOVATIVE ANALYSIS OF MUD VOLCANO PATTERNS IN WESTERN AND SOUTHWESTERN PAKISTAN THROUGH SATELLITE IMAGERY

Mud volcanoes are geological features formed due to pressurized mud, water, gases accompanied by rocks that are expelled to the surface from underground. In Pakistan, there are more than 80 mud volcanoes. However, there is a lack of extensive, thorough mapping and analysis of Pakistan's mud volcanoes in the West and Southwest utilizing satellite image technologies. The present study aims to locate various clusters in South Western and Western regions of Pakistan, and to make a laboratory scale and conceptual model of mud volcanoes in this region to understand the underlying geological and tectonic processes. Firstly, we have used high-resolution satellite images to demarcate and identify various clusters and individual mud volcanoes. Secondly, mud volcanoes of a lesser-known western segment of Pakistan are the unexplored Pishin Basin (Qila Saifullah, Babu Cheena, Zhob). These mud volcanoes occur in distinct patterns which is the regional trend of Makran subduction zone and Pishin Basin. These mud volcanoes occur in clusters (Hingol National Park), and follow the regional structural trend of lineaments. Tracing these lineaments can help in the identification of more mud volcanoes. These active mud volcanoes release methane and hydrocarbons along with mud and water and can be identified by changes in the tone, and texture (Ormara) of the satellite image. However, few fossil or extinct mud volcanoes still have eroded (Gwadar) craters and are relatively diminished in size (~50m). They exhibit a wide variety of surface structures extruding gas and sometimes with bubbles having viscous hot fluid of mud. It could signify the presence of hydrocarbons beneath the surface. Chandragup mud volcano is an attractive place for Hindus, as they consider it a holy place. They are also important as a geoheritage and tourist sight and can generate significant revenue. Hingol National Park is a captivating site for those all over the world who adore to grasp nature thoroughly. These are significant as similar settings in other countries like Azerbaijan, Romania and New Zealand hold immense petroleum, geoheritage, geotourism and geothermal potential.

Mapping the structural configuration of the northern part of the Central Indian Ridge from satellite gravity data using derivatives of the horizontal gradient

This study presents a novel approach to map the structural configuration of the northern part of the Central Indian Ridge from satellite-derived gravity data. The proposed approach is based on a combination of derivatives of the horizontal gradient of gravity anomalies. The robustness of the approach is tested on synthetic gravity examples before applying it to satellite gravity data of the northern part of the Central Indian Ridge. The results obtained from the synthetic examples show that the proposed method can map the structural boundaries more precisely and clearly compared to other techniques, and can avoid producing additional structures in output maps. For real application, the structural features determined from the proposed approach are consistent with the fracture zones that have been identified in the area. The obtained result reveals the prominent lineament trend is in the northeast-southwest direction, which is possibly related to plate movement during the Cenozoic. The result demonstrates a high lineament density that is in agreement with the slow spreading rate of the Central Indian Ridge. My findings also demonstrate that the proposed approach can be considered as a valuable tool in mapping structural boundaries.

Magnetic response contrast of Oligo-Miocene basaltic magmatism and structural control during its ascent at the northern tip of the Red Sea Rift

Oligo-Miocene volcanic activity has occurred along the northern Egyptian margin of the Red Sea Rift system, leading to the creation of small-volume monogenetic volcanoes. This research delves into the morphology and setting of these rift-related volcanics by combining aeromagnetic data, remote sensing, and field verification. Basaltic exposures in the study area were mapped using False Color Composite (FCC) and band ratios in Landsat 8 OLI data. In a map view, these mappable volcanic rocks appear as discrete semi-circular basaltic bodies and as discontinuous dikes. The basaltic bodies are aligned along ENE and NW-oriented zones, with most dikes orientated NW-SE. Multiple isolated high magnetic zones with NE and NW orientations were identified. Most basaltic outcrops coincide with high magnetic zones except for Gabal Abu Treifiya along the Cairo-Suez Road. The integration and combination of three layers of surface and subsurface structure patterns reveal an array of variance. The dominant trend of surface and deeper structural lineaments is NW-SE and NE-SW respectively. In contrast, shallow structural lineaments have NW-SE, NE-SW, E-W, and N–S trends. Long linear grabens result from the pairing of NW-SE normal faults. The basaltic occurrences such as Qattamiya and Abu Treifiya are located at the intersection of the NW-SE and E-W normal faults along the NW-SE linear grabens. The field investigation at both locations reveals a polyphase magmatic feeding system manifesting in the surface today as coherent and volcaniclastic rock units. This suggests a diverse range of eruptive styles through a complex feeder system that involves more than one volcanic cone. Though the two areas have good basaltic exposures, yet they have different magnetic responses. The severe alteration of Abu Treifiya's volcanic rocks into nonmagnetic minerals assemblage of zeolite, smectite, calcite, and hydrolysis of basaltic glass diminishes the expected high magnetic anomaly. This study contributes to our knowledge of Rift-related volcanism and the factors influencing the distribution of these volcanic materials.

The Main Lineament Trends of Central Iraq, Depending on the THD of Residual Gravity and Magnetic Maps Obtained from Four Upward Continuation Levels

The upward continuation was used to obtain central Iraq's residual gravity and RTP magnetic maps at elevations 2, 12, 16, and 22 km. These maps are processed by the Total Horizontal Derivative (THD) technique to detect the main lineaments that represent the boundary of subsurface sources or faults. The obtained lineaments trends represented on the rose diagram and the main trends in the study area were found. The lineaments (faults) orders from the main trend descending, from gravity data, are N55W, N45W, N35W, N-S, and N65W, respectively, for the four considered upward elevations. The length of the faults obtained from gravity data ranges from 40-250km, while the length of faults obtained from magnetic data ranges from 20-100km. The lineament from the main trend descending, from magnetic data, are NS, N55W, N35W, N45W, N45E, N35E, N65W and N55E, respectively. The lineaments obtained from magnetic data indicate that the main trend in shallow sources is NW-SE, while for deep sources; the main trend is N-S. The NW-SE fault trends obtained from gravity data are related to the Najd faults system, while the N-S fault trends are related to the Nabitah system. Generally, it is indicated from the analysis of lineaments of gravity and magnetic data that the NW-SE is the main trend of shallow structures in most areas of central Iraq.

Study of the seismic activity of the Almalyk-Angren industrial zone based on lineament analysis

In this work, an automated lineament analysis was carried out to search for earthquake precursors for the territory of the Almalyk-Angren industrial zone in Uzbekistan. The seven events with a magnitude of about 3 were selected for analysis. The Landsat 8 satellite images were processed using the automated lineament detection method in the LEFA software. The processing steps included detecting line elements in raster images, calculating the characteristics of the spatial distribution of line elements, and combining collinear linear elements into lineaments. The analyses of the cyclicality of precursors before and after earthquakes were based on the study of the distribution of the lineament trend in the study area using rose diagrams and lineament density maps. The results showed a change in the dynamics of the lineament structure. The statistics of the number of lineaments showed that their increase begins almost 20 days before the event, reaches its maximum about 1 – 2 days before the earthquake, decreases starting from 14 days after the earthquake, and has a minimum value of 1 – 2 months. The main trends observed in the lineament map showed the dominant trend in NS, WE, NW-SE directions.

Refining the origin of thermal water using stable isotope, hydrochemistry and GIS approaches in Jiaoxi, Taiwan

AbstractComprehending the recharge of thermal springs is crucial for preserving the water quality of such springs. However, limited groundwater well data in mountainous areas presents a challenge to determining thermal‐spring recharge areas. This study analyzes the isotopes (δ2H and δ18O) and major ions in rainwater, streamwater, mountain groundwater and thermal spring water in Jiaoxi, located near Taiwan's largest city, Taipei. The results of the isotope‐elevation relationship and GIS recharge analysis indicate that the thermal spring water originated from a remote mountain at elevations of approximately 1170–1480 m, rather than the upstream watershed. The thermal spring water was divided into two groups based on the carbonate saturation index (SI) and isotope composition: the foothill group, which had a positive SI and lower δ value, and the downstream group, which had a negative SI and higher δ value. This study improved the conceptual model of the thermal flow path by demonstrating that the recharge of thermal water is a transboundary regional flow and that the foothill thermal water does not mix with the meteoric water. The revised model also highlights the role of structural lineament trends (faults, fractures and folds) in the movement of regional flow in fractured mountain blocks.

Lineaments Characterization and their Tectonic Significance in Mineralization using Landsat TM Data and Field Studies along Mambilla Plateau, Northeast, Nigeria

Lineament characterization and their tectonic significance in mineralization using Landsat TM data and field studies Along the Mambilla Plateau and environs, northeast Nigeria .The area forms part of the mineralized shear zone of the Northeastern, part of the Basement Complex. The Basement Complex rocks underlie more than two-thirds of the plateau and date back to the Precambrian to early Paleozoic eras. While the remaining part of the plateau and its surroundings are made up of volcanic rocks of the upper Cenozoic to Tertiary and Quaternary ages. Remote sensing imagery data and field measurements were integrated for mapping the structural elements and hydrothermal alteration zones related to mineralization. Tectonically the lineaments trends NE-SW, NNW-SSE, NW-SE, and NS, are the main trends controlling mineralization in the area based on data from remote sensing and field measurements. On the other hand, applying band ratios and the constrained energy minimization (CEM) technique to Landsat-8 data pointed out alteration minerals associated with the hydrothermal fluids. Silica, sericite, and chlorite are the common alteration minerals detected, while goethite and epidote are less common in the alteration zones of the area under study. A combination of CET structural complexity, circular features, and alteration zones produced a potential mineralization map, pointing out numerous prospective zones for mineralization that are proximate to areas where artisanal mining activities are carried out. The predictive map was validated by projecting the known prospect zones in the study area, reflecting an agreement between the known occurrences and the higher classes of the predictive zone. The techniques in the current research can be adopted as a direct indicator for structural mapping and detecting alteration zones related to mineralization elsewhere.

Delineation of lineaments for groundwater prospecting in hard rocks: inferences from remote sensing and geophysical data

Egypt is grappling with water scarcity challenges, which are exacerbated by extensive urban development in arid coastal regions with rugged terrain. Although desalinated water is an alternative source in the remote Halayeib region of Southeast Egypt, its cost increases reliance on groundwater from the intricate aquifers. This study aims to accurately delineate hydro-structural features, known as lineaments, and assess their impact on the groundwater conditions in this promising region. This integrated approach involves the assessment of various spaceborne sensors, including optical (Landsat 8), Digital Elevation Models (ALOS and ASTER-DEMs), and radar (Sentinel-1), using geospatial and geostatistical techniques within the Geographic Information System (GIS). Radar-based sensors, particularly the Sentinel-1A vertical–vertical (S1A VV) polarization, outperform all other datasets in extracting lineaments, yielding 4883 lineaments that correspond to the regional geological faults. These lineaments trend in NE–SW, NNE–SSW, NW–SE, and E-W directions. The results also indicated that both digital elevation models (DEMs) were less effective, showing different orientations with azimuth angles. S1A VV proved to be highly effective in identifying subsurface fractured hard rock terrains beneath thin sedimentary covers, especially in the flat coastal area of Wadi Serimatai, where they intersected natural drainage pathways. Geoelectrical sections confirmed that there are orthogonal subsurface faults extending from fractured basement aquifers to near-surface layers. These faults align with the NE-SW and NNE-SSW directions observed in S1A VV lineaments. Geostatistical analysis revealed that S1A VV structural lineaments, lithological, and hydrogeological factors influence the occurrence of groundwater. This emphasizes the structural control over groundwater and its significant impact on water flow and storage. The study provides valuable insights for groundwater management, guiding decisions related to the development of groundwater resources.

Mapping of the Structural Lineaments and Sedimentary Basement Relief Using Gravity Data to Guide Mineral Exploration in the Denizli Basin

The Aegean Graben System is a complex tectonic structure in Western Anatolia and the Denizli Graben is a member of this system that hosts many geothermal springs, ore deposits, and travertine areas. In this study, the gravity data were analyzed to determine the subsurface geological structures and the depth model of the basin. The Bouguer gravity anomaly has a NW–SE pattern that is consistent with the general trend of the Denizli Basin. The pre-Neogene basement depths range from 0.1 km to 2.3 km. The Denizli Basin is composed of the Çürüksu Basin and the Laodikia sub-basin. The basins have undulated structures with many depressions; the deepest depression region is in the northern part of the Çürüksu Basin, which is close to the Pamukkale Fault Zone. In addition, the new gravity lineament map was obtained by using new-generation edge detection techniques: the tilt angle of the horizontal gradient amplitude (TAHG), and fast sigmoid-edge detection (FSED) of gravity data. The new proposed lineament map shows that the Denizli Basin has complex structures consisting of NW–SE, E–W, and NE–SE trending lineaments, and the major NW–SE trending faults and NE–SW trending lineaments control the main structural configuration. The uplifts and depressions in the basin deposit and the intersection area of lineaments are promising prospective areas for mineral deposits and have energy resource potential.

Mapping and Assessment of Geological Lineaments with the Contribution of Earth Observation Data: A Case Study of the Zaer Granite Massif, Western Moroccan Meseta

The Zaer granitic massif is one of the most important Variscan granitoids in the Central Zone of the Western Moroccan Meseta. It is characterized by a deformation which is manifested by a network of fractures of different scales. Thanks to the technology currently available, many geological studies rely heavily on the mapping of geological lineaments, especially in structural geology. This has become more reliable with access to earth observation data using optical and radar sensors as well as the various remote sensing techniques. Therefore, the objective of this work is to determine the potential of Landsat 8, ASTER, Sentinel 2 and radar Sentinel 1 datasets using the automatic method to extract lineaments. Furthermore, this work focuses on quantitative lineament analysis to determine lineament trends and subsequently compare them with global and regional tectonic movement trends. The lineaments obtained through different satellite images were validated by including the shaded relief maps, the slope map, the correlation with the pre-existing faults in the geological maps as well as the field investigation. Comparison of these results indicates that Sentinel 1 imagery provides a better correlation between automated extraction lineaments and major fault zones. Thus, Sentinel 1 data is more effective in mapping geological lineaments. The final lineament map obtained from the VH and VV polarizations shows two major fault systems, mainly oriented NE-SW and NW-SE to NNW-SSE.

Aeromagnetic data interpretation of the northern Kontum massif (Vietnam) for mapping subsurface structures

The Kontum massif plays a key role in the tectonic development of the central Vietnam terrane. However, most of the northern part of the Kontum massif is covered by sediments. In this paper, we determine for the first time the subsurface structures of the area using aeromagnetic data. We have evaluated the effectiveness of six enhancement techniques on a synthetic model before applying these techniques to real aeromagnetic data of the study area. The results obtained from these techniques show that the study area is dominated by E-W and ENE-WSW trending lineaments and the depths of most of these structures range from 50 to 550 m. The findings also show some probable granitic intrusions in the study area. Our study provides the first magnetic interpretation for a better understanding of the structural features of the northern Kontum massif.

Morphotectonic and morphostructural investigation in northwestern Minas Gerais State, Brazil: a lineament mapping assessment

This study aimed to investigate whether linear natural features are associated with structural or tectonic control of landforms and current drainage patterns in northwestern Minas Gerais State (Southeastern Brazil). To answer this question, more than 1,700 lineaments were manually mapped in a broader area encompassing the Paracatu and Urucuia River catchments. One satellite image scene (Operational Land Imager/Landsat-8), three different digital elevation models (Shuttle Radar Topography Mission, Advanced Spaceborne Thermal Emission and Reflection Radiometer-Global digital elevation model, and Advanced Land Observing Satellite-Phased Array L-band Synthetic Aperture Radar), and digitised analogical maps (geologic and topographic maps) were used to draw linear geometric features representing the lineament population. The resulting vector databases were integrated in a Geographic Information System for quantitative and spatial analyses, which resulted in two main trending lineament sets: NNW-SSE and NE-SW. Subsequent field assessments revealed that numerous lineaments from the first set were correlated to the formerly Upper Precambrian reverse and strike-slip faults. The second set were correlated to NE-SW normal faults derived from the Mesozoic-Cenozoic tectonic event following the breakup of Gondwana. These datasets contribute to a better understanding of the regional-, sub-regional-, and catchment-scale features underlying the structural control of the drainage network arrangement and pattern, which present long straight channels and are interrupted by anomalous and prominent bends that strictly fit major structural directions.

Sedimentary Thickness and Upper Crustal Structure of the North Cambay Rift, India Deduced from Gravity Data: New Evidence of Pre-trappean Sediments

Abstract A gravity survey was carried out to estimate the sedimentary thickness and to map upper crustal geometry over the northern part of the Cambay rift. Structural lineaments delineated using the total horizontal gradient of the Bouguer anomaly indicate a major lineament trend in the NW-SE direction. Results of the density modelling using residual Bouguer anomaly reveal the average thickness of the Quaternary and Tertiary sediments to be between 0.5 and 6 km, while the Deccan trap thickness varies between 0.5 and 3 km. It is seen that the Mesozoic sediment (maximum thickness ~0.6 km) is sandwiched between the Deccan trap and granitic basement, which indicates the possible existence of a rift in the late Jurassic-early Cretaceous. Based on the residual Bouguer and density modelling results, the spatial locations of the NE-SW trending Unhawa ridge and the N-S trending Mehsana uplift are provided, which are believed to be the remnant rock of the Proterozoic age. A high-density body, interpreted as a magmatic underplating layer, is also found in the lower part of the middle crust along the central part of the rift, which continues in the lower crust. The magmatic underplating layer is formed during the Reunion hotspot and lithospheric interaction in the Cretaceous period.