Interpretation Of Aeromagnetic Data Research Articles

Imaging and modelling the subsurface structure of the Rungwe Volcanic Province in SW Tanzania with aeromagnetic data: An improved structural map to support geothermal exploration

The Rungwe Volcanic Province (RVP) in the East African Rift System, SW Tanzania, provides a unique opportunity to investigate geothermal resources in the context of particularly complex continental rifting processes. To support geothermal resource targeting in the RVP, we present a revised neotectonic structural map based on an interpretation of aeromagnetic data constrained by 2D-forward modelling of magnetic anomalies integrated with the distribution of previously reported faults, seismic epicentre locations, 3D magnetotelluric resistivity models and surface geothermal manifestations. Magnetic anomalies in the RVP, including the nationally prominent Mbeya anomaly, are related to the high magnetic susceptibility or remanent magnetism of Precambrian rocks and Cretaceous carbonatite intrusions buried in the rift under a varying thickness of non-magnetic sediments and volcanic rocks. Magnetic lineaments are related to structures controlling the geometry of the Precambrian rocks and concealed dikes and the thickness of the sediments and volcanics. The recent Ngozi and Rungwe trachyte volcanics have relatively low magnetic susceptibility comparable to the low susceptibility of the sediments in the rift basins. The revised neotectonic structural map shows prominent NW, NE and NS-trending magnetic lineaments that correlate with previously reported faults and alignments of seismic epicentres in the study area and with the regional trend of the rift segments. The NE-trending magnetic lineaments are consistent with interpretations of the current stress field in the RVP. The main volcanoes in the RVP, Ngozi, Rungwe and Kiejo (also known as Kyejo and Kieyo), are aligned with the NW-trending linear magnetic feature joining the Lupa and Livingstone rift border faults. This lineament is intersected and frequently displaced by the NE and NS-trending lineaments, suggesting that the NE to NS-striking structures are younger. The Rungwe and Ngozi volcanoes as well as numerous ‘’monogenetic’’ eruption centres and the Mwakaleli caldera, which originated ca. 2 Ma ago (Ebinger et al., 1989) following a large explosive eruption emplacing widespread ignimbrite deposits, are located within a zone of low-intermediate magnitude magnetic features forming a basin-like structure surrounded by magnetic high anomalies of the Precambrian basement structures. We interpret the intersections between the NW-trending intra-rift faults and the NS and NE-trending faults as favourable locations for wells to target high permeability within the geothermal resource conceptual models previously constructed using 3D MT resistivity imaging integrated with supporting geoscientific data. The intersections provide a focus area for follow-up ground mapping of subtle features that may be associated with very recent fault movement.

Kinematics of the Clarke River Shear Zone (northeastern Australia) and implications for the tectonic evolution of the Tasmanides

The Clarke River Shear Zone marks the boundary between the Thomson and Mossman orogens in the northeastern Tasmanides. To better understand the kinematic history of this east-northeast-trending shear zone, and its role during the tectonic history of eastern Gondwana, we investigated rock deformation along a segment of the Clarke River Shear Zone. Based on field observations, interpretation of aeromagnetic data and microstructural analysis, we show that the Clarke River Shear Zone experienced at least three phases of reactivation. Gently plunging stretching lineation and kinematic indicators, such as steeply plunging asymmetric folds and asymmetric porphyroclasts, correspond to an early phase of sinistral strike-slip ductile shearing. Subsequent general dextral shear deformation is suggested based on the presence of S-tectonites, symmetric porphyroclasts and kinematic indicators with dominant dextral and subordinate sinistral shear senses. This phase, which occurred under amphibolite-facies metamorphic conditions, was contemporaneous with the emplacement of the Craigie Tonalite, for which we obtained a new zircon U–Pb crystallisation age of 410.3 ± 1 Ma. A later reactivation phase along the Clarke River Shear Zone, under brittle conditions, is indicated by the presence of cataclasite zones and chlorite–epidote alteration. Based on our findings, and regional information on the tectono-magmatic evolution of northeastern Queensland, we suggest that the Clarke River Shear Zone was possibly a sinistral transform fault during the Silurian. During the Devonian, it is possible that deformation along the Clarke River Shear Zone was related to the transition between the non-retreating subduction zone in the north, and the highly mobile (retreating) plate boundary farther south. However, the dextral kinematic component associated with this deformation is not fully explained. Brittle deformation, likely associated with dextral transpression during the Carboniferous, marked the last stage of activity along the Clarke River Shear Zone.

Lithology and subsurface structures related to gold mineralisation in the Kibati prospect, Mozambique belt in eastern Tanzania, with implications for gold exploration

This paper provides an insight into the structures, lithologies, and potential zones and their relationships to gold mineralisation that were investigated to decipher the controls of gold mineralisation at the Kibati Gold Prospect within the Mozambique Belt. Although the Kibati area is located within the gold mineralised zone, lithology and subsurface geological structures associated with gold mineralisation are not well studied. The available high-resolution aeromagnetic data have not yet also been analysed and interpreted to derive geological features that are useful in mineral exploration. The investigation of the structures and lithologies was accomplished through integrated interpretation of high-resolution aeromagnetic data, ground magnetic data, geological mapping, and rock sampling. Aeromagnetic and ground magnetic results reveal the presence of two structural systems, which were previously not identified that trend in NW–SE and NE–SW, with the NW–SE being the dominant control of gold mineralisation. The subsurface structure with NW–SE trending controls the mineralised fluids as a consequence of gold mineralisation in the surface lithologies. Petrography and geological mapping show that granitic gneiss, garnet-biotite quartzo-feldspathic gneiss, dolerite, and amphibolite are the main exposed outcrops where the first two identified types of gneisses, based on their protolith, were previously not specified. Based on the gold assay results, which are persistent and collinear to the structural trend of NW–SE picked out by magnetic data, two (2) potential blocks (A and B) were identified. The trend of the structure in blocks A and B when overlaid with gold anomalies indicates that most of the gold concentrations are located in block B and the highest value of gold concentrations is located in block A where gold values range from 10.19 to 19.680 g/t in block A and 0.0623 to 4.419 g/t in block B. The difference in gold values between blocks A and B is due to the variation in the degree of alteration. The integration of the results indicates that the gold mineralisation in the Kibati area is structurally controlled and concentrated in shear zones. The findings therefore, indicate that the Mozambique Belt is potential for gold mineralisation and provide a warrant for future plan for gold exploration.

Geothermal resource potentials estimation from the interpretation of aeromagnetic data over parts of Southwestern Nigeria

In a bid to explore unconventional electricity generation sources and reduce effects of fossil fuels, this study evaluates geothermal resource potentials over parts of Southwestern Nigeria, precisely depth to the bottom of magnetic source (DBMS), heat flow, geothermal gradient and their relationships. Regional-residual anomaly separation was conducted, and spectral analysis was applied on the residual anomaly component of 14 aeromagnetic data sheets. Depth to the bottom of magnetic source varies between 1.87 and 6.26 km, with average value of 3.50 km, heat flow varies between 23.18 and 77.38 mWm−2, with average value of 43.79 mWm−2, while geothermal gradient varies between 9.27 and 30.95 oC/km with average value of 17.52 oC/km. Northcentral region has the highest heat flow (77.4 mWm−2), followed by Northeast (68.3 mWm−2), Southwest has the least (< 40.0 mWm−2) while Southeast has values in between the extremes. A comparison between the average heat flow and that of ‘thermally stable’ continental regions of the world (60 or 65) mW/m2 gives 72.98 or 67.37% respectively. The estimated heat is probably from mantle plumes, radioactive sources or heat generated from pressures within basements that are overlaid by thick thermally insulated sediments, hence hot magmatic fluid flows into fractured basement and cause hydrothermal alterations of surrounding rocks. Since most geodynamic operations depends on thermal structure of the earth’s crust, the result of this study has undoubtedly contributed significantly to the body of existing thermal knowledge and closed the information gap regarding crustal temperature distribution at depth in Southwest part of Nigeria and Nigeria in general.

Delineation of structural features and hydrothermal alteration zones using integrated geophysical data of part of North-central Nigeria

Delination of possible structural features in part of Nigeria Northcentral region has been performed using high-resolution aeromagnetic and aero radiometric data. The objectives of this work are to identify and harness the factors responsible for alteration zones which can serve as a potential mineralized sources for exploration purpose in the area. To achieve this purpose, mathematical techniques such as First Vertical Derivative, Analytic Signal, and Centre for Exploration Targeting (CET) grid were performed on the aeromagnetic data analysis and interpretation; in addition, ratios of radioelements were obtained to support the mapping process. The results obtained showed that the area is dominated by structures trending Northeast-Southwest, Northwest, Northeast, Eastwest and Northsouth directions, although the structures trending Northeast-Southwest were found to be most predominant and considered as orientations of mineral deposits in the area. Also, aero radiometric analysis based on the concentrations of Potassium, Uranium, Thorium and their ratios revealed lithological units and hydrothermal alterations of the area. However, this study concluded by identifying and harnessing the factors responsible for alteration zones which can serve as a potential mineralized sources for exploration purpose in the area.

Processing and interpretation of magnetic data in the Caucasus Mountains and the Caspian Sea: A review

<p>With the rapid development of aeromagnetic (primarily uncrewed) methods for measuring the magnetic field, the possibility of detailed magnetic research in hard-to-reach mountainous areas, forested areas, swamp areas, desert areas, and water areas has emerged. The conditions for interpreting the magnetic field are most difficult due to the vector nature of the magnetic properties of rocks, the wide range of their properties, and the presence of residual magnetization. The physical and geological conditions of the territory of Azerbaijan are characterized by rugged terrain relief, inclined magnetization (~58°), and complex geological environments. Along with using a probabilistic approach, deterministic methods for solving inverse and direct problems of geophysics become of great importance since it is possible to identify relatively extended reference boundaries and analyze magnetic anomalies from separate bodies of relatively simple shape. The article briefly outlines the main stages of processing and interpreting magnetic data under complex environments. The theoretical examples discussed include a block diagram of various disturbances, interpretive models of thin and thick beds, an intermediate model, a thin horizontal plate, and a horizontal circular cylinder on the flat and inclined surfaces under inclined magnetization conditions. The process of assessing magnetization on sloping terrain relief is shown. The presented field examples for the Caucasus Mountains show the quantitative interpretation of aeromagnetic data at the Big Somalit and Guton sites (southern Greater Caucasus, Azerbaijan), a deep regional profile through the Lesser and Greater Caucasus, magnetic field studies in the area around the Saatly superdeep borehole (Middle Kur depression between the Greater and Lesser Caucasus), and 3D magnetic field modeling at the Gyzylbulag gold deposit (the Azerbaijani part of the Lesser Caucasus). In the Caspian Sea, we demonstrated the use of an information parameter to identify faults in the Bulla hydrocarbon field (Gulf of Baku) and, for the first time, obtained the relationship between the generalized aeromagnetic data (2.5 kilometers over the mean sea level) and the central area of the mud volcanoes distribution in Azerbaijan.</p>

Structural and Tectonic Interpretation of Nkalagu and Environs Using High-Resolution Aeromagnetic Data

The aeromagnetic survey carried out by the Geological Survey of Nigeria between 2003 and 2010, provided high-resolution aeromagnetic data used in this study. The study area is Nkalagu and its environs. It lies within latitudes N6o00 and N6o30 and longitudes 8o00 E and E. The geology of the study area is predominantly the geology of the Lower Benue Trough. The purpose of the study is to determine the depth of the basement and delineate the basement morphology and structural features associated with the subsurface of the study area using the structural and tectonic interpretation of aeromagnetic data. This will create indebt knowledge of the geology of Nkalagu and its environs. The Aeromagnetic data obtained were subjected to various data preprocessing enhancement techniques these include relief imaging, vertical and horizontal derivatives, analytic signal, apparent susceptibility mapping, automatic gain control, and spectral analysis. Results of the study revealed lineament with trend directions in the N-S, NE-SW, NW-SE, and E-W, with the NW-SE trend being dominant. When subjected to 2-D spectral analysis, it revealed a two-layer depth model; the shallow magnetic sources and the deep magnetic sources with average depths of 1.041 km and 3.574km respectively. Similarly, the average sedimentary thickness of the study area was estimated at approximately 3.6km.

Serra Geral Group plumbing system and 3D geological framework in Morungava region, southern Paraná–Etendeka LIP (Brazil): Combining 3D geologic and magnetic models

A coupled 3D geophysical–geological model was constructed by integrating aeromagnetic data and a prior 3D geological model of the Morungava region (Araújo et al., 2023 [manuscript submitted for publication]), situated at the southeastern border of the Paraná–Etendeka large igneous province (LIP) in Brazil. Aeromagnetic data interpretation and modeling (qualitative and semi-quantitative interpretation, susceptibility inversion, forward modeling, and magnetic vector inversion (MVI)), along with magnetic susceptibility data, complemented understanding of the Serra Geral Group feeder system in the subsurface (spatial distribution, depth, and geometry) and illuminated the crustal framework at different depths. We recognized three major NE-elongated geophysical domains (NW, Central, and SE), which were interpreted as basement compartments: the Tijucas, Pelotas, and Jaguarão terranes. The final integrated 3D geophysical–geological model encompasses the stratigraphic framework and the Serra Geral Group plumbing system in the study area, that comprises: two dike systems, four subvolcanic complexes with associated nested sills, and two intrusive ring complexes. This is the first time that these aeromagnetic data have been combined with borehole and 3D geological models.

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.

An aeromagnetic denoising-decomposition-3D inversion approach for mineral exploration

Reduction of aeromagnetic noise and extraction of mineralization-related residual anomalies are critical for aeromagnetic data processing in mineral exploration. This study introduced a multifractal singular value decomposition (MSVD) method to remove the noise and improved the bi-dimensional empirical mode decomposition (BEMD) algorithm to extract residual magnetic anomalies. It is shown that MSVD and improved BEMD could effectively reduce the noise and extract residual magnetic anomalies. Then, a wavenumber–domain iterative approach is applied in 3D imaging of magnetic anomalies and gradients with depth constraints, which is a rapid tool for qualitative and quantitative interpretation of magnetic data and is suitable for rapidly imaging large-scale data. The 3D inversion result is verified by four geological sections along the regional tectonic directions and some drilling holes on the deposits. It is revealed that this proposed approach is practical and effective in dealing with aeromagnetic data interpretation and inversion for mineral exploration.

The role of structural inheritance in the tectonic configuration of the Moroccan Meseta Coastal Block: Insights from morpho-structural and aeromagnetic data

The Coastal Block (CB) of the Western Meseta (Morocco) is located between the Atlantic passive margin and the Middle and High Atlas Mountains. In this contribution, a morpho-structural analysis using topographic data and an aeromagnetic data interpretation have been integrated to map tectonically related structures and to unravel the surface-subsurface faults interaction and their geodynamic implications in the CB. The morpho-structural analysis allowed the structural lineaments mapping through the processing of the topographic and hydrographic data. The application of derivatives operators on the magnetic anomaly map reduced to the pole allowed the assessment of the tectonic framework. The visual integrated analysis of surface and subsurface structures allowed to establish a synthetic structural map of the CB. Several N–S to NNE-SSW, NW-SE and NE-SW oriented fault systems were identified, some of which were confirmed and others were newly outlined. Four geometrically horst and graben type blocks were well distinguished, including the Triassic Basins of Berrechid to the north and of Doukkala to the south separated by the Casablanca Paleozoic block. Meanwhile, the Sahel represents an uplifted zone separating the Doukkala Basin from the continental shelf to the west. Rooted faults bounding these blocks, which are heavily inherited from the pre-Mesozoic tectonic events, record variable reactivation indicators related to the Neogene-Quaternary Atlasic shortening.

Detection of potential hydrocarbon accumulations at Qaret El-Soda area, Western Desert, Egypt, based on airborne geophysical survey data

Airborne spectral gamma-ray survey data were processed using Th-normalization technique for oil and gas exploration in the Qaret El-Soda area, Western Desert of Egypt. This technique was applied to suppress the effects of surface lithology, which are the main factors influencing the variation of radioelement content in rocks. Normalization of K and U by thorium yielded residual potassium and residual uranium estimates. Possible occurrences of new hydrocarbon microseepages were determined by mapping low values of residual potassium and high values of residual uranium relative to potassium, which are indicated as DRAD values, which were obtained by subtracting residual potassium from residual uranium values (eUresid – Kresid). Lower residual values of K, which were associated with higher DRAD anomaly values, highlight areas of prospective hydrocarbon accumulations. The obtained results from quantitative analysis and interpretation of aeromagnetic data show sufficiently thick sediments, probably suitable for the accumulation of hydrocarbons. This means that the study area may possess a potential for hydrocarbon exploration if supported by other detailed geophysical and geochemical exploration techniques.

Aeromagnetic expression of the central Nagssugtoqidian Orogen, South-East Greenland

The Paleoproterozoic Nagssugtoqidian Orogen is one of the principal tectonic features related to the assembly of Nuna, extending across Greenland from east to west and forming an orogenic belt separating the North Atlantic Craton on the south from the Rae Craton on the north. In South-East Greenland, the Ammassalik Intrusive Complex (AIC) (∼1910 to 1870 Ma) occupies the central part of the orogenic belt, was formed by subduction- and magmatic arc-related processes, and has significant potential for undiscovered deposits of critical minerals. Previous interpretations of aeromagnetic data have been hindered by terrain effects, and we use a novel mix of geophysical analysis tools to develop new tectonomagmatic interpretations of the central Nagssugtoqidian Orogen in South-East Greenland. These interpretations extend into areas covered by ocean and ice. Results show that Archean rocks of the juxtaposed North Atlantic (Isertoq Terrane) and Rae (Kuummiut Terrane) Cratons are relatively weakly magnetized (with the exception of rocks of the Schweizerland Terrane) and have a NW-striking structural fabric that likely formed or was enhanced during the Nagssugtoqidian Orogeny. The AIC is structurally complex, with weakly magnetized metasedimentary rocks, and both weakly and strongly magnetized intrusions, arrayed in a NW-striking tectonic fabric. The strongly magnetized intrusions are largely concealed and distributed in a broader and more spatially complex fashion than previously known, suggesting that additional areas may be considered for mineral exploration. Strongly magnetized NW-striking dikes are imaged within the AIC, where they are spatially closely related to the strongly magnetized intrusions, and extend southward into the North Atlantic Craton (Isertoq Terrane). This spatial pattern of arc magmatism is consistent with previously developed models of SW-directed subduction that preceded collision during the Nagssugtoqidian Orogeny. The strongly magnetized Ammassalik Batholith (∼1670 Ma) and related intrusions form a cluster of plutons within ∼ 50 km of the Nagssugtoqidian suture. Their tectonomagmatic setting is unknown, although are speculatively related to delamination of a lithospheric keel formed during the Nagssugtoqidian Orogeny ∼ 200 m.y. prior. Numerous strongly magnetized NNE-striking Paleogene dikes, related to the opening of the Atlantic Ocean, are imaged cutting most other geologic units.

Interpretation and modeling of aeromagnetic data from helicopter surveys of the Morobe goldfield, Papua New Guinea

AbstractWe interpreted and modelled aeromagnetic data from helicopter surveys of the Morobe goldfield, Papua New Guinea, by comparing gridded magnetic data with mapped surface geology. In some cases, geologic units may be recognized and distinguished based on contrasts in magnetic intensity and texture, including the Morobe Granodiorite, Kaindi Metamorphics, Bulolo Volcanics, and Langimar Beds. Magnetic anomalies occur due to intrusions of Edie Porphyry and related igneous rocks that are associated with gold mineralization. Numerous faults control the size and shape of the intrusions. Magnetic anomalies of interest were identified in gridded data from high‐resolution surveys and modelled using flight line data. Two‐dimensional magnetic models included dipping slabs with thicknesses of 100–400 m. Three‐dimensional models were prepared, including a dipping tabular body and a dipping cylinder. A 2008 survey of the Papuan peninsula sponsored by the European Union (EU) provided continuous coverage of the Morobe goldfield area and helped resolve regional features that were only partially covered by previous smaller surveys. In particular, the EU survey covers the full length of the Sunshine Fault and greatly extends coverage of outcrops of the Morobe Granodiorite and Langimar Beds. The EU survey contains isolated anomalies south‐west of Wau that may correspond to intrusions of Edie Porphyry, Morobe Granodiorite.

A Data-Driven OBE Magnetic Interference Compensation Method.

Aeromagnetic compensation is a technology used to reduce aircraft magnetic interference, which plays an important role in aeromagnetic surveys. In addition to maneuvering interferences, the onboard electronic (OBE) interference has been proven to be a significant part of aircraft interference, which must be reduced before further interpretation of aeromagnetic data. In the past, most researchers have focused on establishing linear models to compensate for OBE magnetic interference. However, such methods can only work using accurate reference sensors. In this paper, we propose a data-driven OBE interference compensation method, which can reduce OBE interference without relying on any other reference sensor. This network-based method can integrally detect and repair the OBE magnetic interference. The proposed method builds a prediction model by combining wavelet decomposition with a long short-term memory (LSTM) network to detect and predict OBE interference, and then estimates the local variation of the magnetic field to remove the drift of the interference. In our tests, we construct 10 semi-real datasets to quantitatively evaluate the performance of the proposed method. The F1 score of the proposed method for OBE interference detection is over , and the RMSE of the compensated signal is less than nT. Moreover, we also test our method on real signals, and the results show that our method can detect all interference and significantly reduce the standard deviation of the magnetic field.

Identification of potential mineral exploration targets from the interpretation of aeromagnetic data covering the Sirwa region (Central Anti-Atlas, Morocco)

Situated at the junction between the Moroccan High Atlas and the Anti-Atlas, the Sirwa Massif has always been a perfect target for mining exploration for its unique geological characteristics that provide an economically valuable concentrations of metals. It corresponds to a crustal uplift at an elevation above 2000 m that were slightly folded and lifted during the Hercynian and Alpine orogeny. The structural settings of this area are very complicated due to the acute shortage of surface and subsurface structural data. The aeromagnetic data represents a powerful tool for the identification and the delineation of the poorly exposed faults, that could promote the development of new ore deposits.The processing of the residual magnetic map was carried out to locate anomalies, define the trends and boundaries of the buried structures and identify the magnetic contacts that might represent faults, fractures or lithologic boundaries. This is done by the reduction to the north pole (RTP) filter and several edge detectors processes (i.e., total horizontal derivative, the tilt angle derivative and the 3D-Euler deconvolution). The orientations of lineaments extracted from the total horizontal derivative and Tilt derivative maps predominantly suggest NE-SW to ENE-WSW trending structures, in agreement with the post-Pan-African rifting event. However, we have identified a few NW-SE and NNW-SSE trending lineaments probably related to the recent Variscan movements. The 3D Euler deconvolution (ED) suggests a depth solution that ranges from 600 m to 3400 m. The deepest lineaments have an ENE-WSW direction, and the shallowest with a depth of about 600 m, shows a NE-SW/NW-SE direction. These results reveal new tectonic features that can be useful for future mine exploration

Results of geological and geophysical study of the deep structure of Angara and Trans-Baikal mantle plumes and their connection with mineral deposits.

The purpose of the article is to consider the issues of geological and geophysical interpretation of the data of balloon and satellite magnetic measurements along the regional profile crossing the territory of the Angara-Baikal region. In order to conduct scientific research along the regional Trans-Siberian geological and geophysical profile A-B the author used various geological and geophysical materials including the magnetic field digital data measured by the MAGSAT artificial Earth satellite and a balloon; data on the values of the electrical resistivity in the mantle of this region; geothermal data; seismic data on the location of earthquake hypocenters in the area of the profile under investigation. The research methods involved multilevel measurements of satellite and balloon magnetic fields, which significantly expanded the possibilities of geological and geophysical interpretation of the data obtained. The conducted study revealed that the geological and geophysical interpretation of multilevel aeromagnetic data allows for a reasonably accurate determination of the location coordinates and lithospheric penetration depth of tectonic faults associated with the Angara and Trans-Baikal mantle plumes, which are of significant interest in terms of exploration of coal and uranium deposits. The spatial and depth characteristics of tectonic faults obtained from balloon and satellite data are confirmed by a set of analyzed independent geophysical data: magnetotelluric sounding, geothermy, seismology and other geophysical methods. In conclusion it should be noted that the author has demonstrated the application possibility of satellite and balloon magnetic surveys for the study of the deep structure of the Angara and Trans-Baikal mantle plumes. In addition, it was found out that according to balloon and satellite magnetic data, large deep tectonic faults in the lithosphere (Barguzinsky, Ikatsky, Tukolamsky, Tungirsky) can be identified, which also allow marking various subhorizontal boundaries of lithospheric layers in the location area of the Angara and Trans-Baikal mantle plumes using special points of the magnetically active zones of these faults. The practical significance of the conducted research is in the identification of the spatial relationship between the location of the Angara mantle plume and coal deposits of the Irkutsk basin, as well as uranium deposits in the zone of the Trans-Baikal mantle plume.

Geothermal resources prospecting using magnetotelluric and magnetic methods at Al Ain AlSukhuna-Al Galala Albahariya area, Gulf of Suez, Egypt

Recently, several urban and service development projects were carried out at the “City of Al-Galala Mountain”, along the Egyptian Gulf of Suez, between Al Ain Al-Sukhuna and Al-Galala Al-Bahariya Plateau. This region is adjacent to the Gulf of Suez rift, which is an active geothermal area, as indicated by the geothermal surface manifestations, such as thermal hot springs. It is a zone between two tectonic plates, which is expected to have several geothermal reservoirs; consequently, it represents a potential area for geothermal prospecting. Aeromagnetic data interpretation was performed to define the deep and shallow structures in the study area and their distribution to select a suitable site and perform more detailed prospection. Consequently, two sites were chosen to conduct a detailed study, with land magnetic and (1D MT) to discover variations in conductivity (resistivity) and fix the depth of predicted geothermal reservoir as well as the distribution of deep and shallow faults which can facilitate geothermal solutions flow and injection to exploit the geothermal source energy. The obtained results showed that the study area is intensely faulted with major NW-SE trend and minor E-W trend. Meanwhile, the (MT) results show several conductive and resistive zones at different depths, which could be correlated with faulting zones, suitable to predict geothermal sources and aquifers.

Crustal architecture of North Singhbhum Mobile Belt, Eastern Indian Shield: Constraints from two‐dimensional and three‐dimensional modelling of Bouguer gravity and aeromagnetic data

The North Singhbhum Mobile Belt (NSMB) that lies in the Eastern Indian Shield between the Chotanagpur Granite‐Gneiss Complex (CGGC) and the Singhbhum Craton (SC) provides a unique opportunity to understand the Proterozoic crustal evolution of the Indian shield. In the present study, an integrated interpretation of petrophysical, Bouguer gravity, and aeromagnetic data was carried out to examine the crustal architecture and structural framework of the region. Three‐dimensional (3‐D) inversion of the aeromagnetic anomalies reveals that the magnetic basement depths range from 0.2 to 9.0 km in the region. The crustal models obtained from two‐dimensional (2‐D) and 3‐D forward modelling of potential field data reveal the Moho at 37–38 km depth beneath the NSMB and at a relatively deeper depth of 39–40 km and 40–44 km beneath SC and CGGC, respectively. Further, the distinct gravity high and the coinciding bipolar magnetic anomalies associated with the Dalma Formation can be attributed to the mafic/ultramafic intrusions. Gravity models across the Singhbhum Shear Zone (SSZ) and South Purulia Shear Zone (SPSZ) exhibit the crustal density inhomogeneity and Moho offset, typical of ancient suture zones of Precambrian terrains. In comparison, the absence of such crustal‐scale signatures across the North Purulia Shear Zone represents its intracratonic nature. Further, the Bouguer gravity and aeromagnetic signatures across the SPSZ, together with the crustal architecture and metamorphic ages, suggest that SPSZ marks the eastward continuity of the Gavilgarh‐Tan Shear Zone along which the amalgamation of northern and southern Indian cratonic blocks possibly took place at ca. 1.0–0.9 Ga.

Investigating groundwater recharge potential of Notwane catchment in Botswana using geophysical and geospatial tools

Study regionThis study is conducted over the Notwane Catchment Area (NCA) in Southeastern Botswana using geospatial and geophysical tools. Study focusGeospatial and geophysical tools, which provide spatial information for both the surface and subsurface have been widely used in groundwater exploration because of their capability in detecting physical properties that are related to groundwater phenomena. In this research, relevant remotely sensed data including aeromagnetic data and satellite images were used to identify potential groundwater recharge zones within the NCA as a contribution towards improved water resources management amid the changing climate. The multi-disciplinary approach used could offer a more reliable way to identify potential recharge zones, particularly in semi-arid hard rock terrains. New hydrological insights for the regionAssessment of groundwater recharge potential looking at remotely sensed data revealed that built-up areas expanded significantly between 2009 and 2019 with implications for run-off and flooding. Through aeromagnetic data interpretation of Euler deconvolution solutions and apparent susceptibility computations, weathered zones and geologic lineaments, mainly dykes and faults, indicating areas with increased secondary porosity were identified. Consequently, the groundwater recharge optimization model was used to determine areas with higher recharge potential which lie on the central part of the NCA, northeastern margin and the southernmost part bounded by topographical relief of hills with thick vegetation. These areas are characterized by approximately 200 m depth of weathering and predominantly east-west structural features.