This research study integrates geophysical, satellite remote-sensing, and surface-geology data to derive and enhance the structural and geological understanding of the Busaiya area in southwestern Iraq. An arid climate characterizes this area, which covers 19,500 km2. Tectonically, the Busaiya area is located in the stable part of the Arabian Platform. In this paper, gravity, magnetic, and seismic reflection data have been investigated to study the surface and subsurface geological structure in more detail, since they could have potential importance in mineral and oil exploration. The interpretation of the gravity and magnetic data shows that the Busaiya is a sub-basin structure located at the southeastern edge of a basement block structure and has been reactivated and subsided throughout geological history. The boundaries and structures of the sub-basin are delineated using edge-detection filters, while depths are determined with the tilt-depth method. Additionally, a two-dimensional depth inversion model, oriented east-northeast and based on gravity data from the northern part of the sub-basin, reveals both lateral and vertical variations in density contrasts. The lineaments revealed by the Global Digital Elevation Model imaging indicate a high density, while the Sentinel-2 data illustrate notable rock deformation along the edges of the sub-basin. The high density of the lineaments could allow the evolution of near-surface, good-quality groundwater aquifers. Regions within the Busaiya sub-basin are recommended for mineral and oil exploration according to their structural situation. It is concluded that the area has undergone significant stress-induced deformation, resulting in subsurface faulting and surface deformation. Moreover, the area has been affected by the anticlockwise movement of the Arabian Plate, which has contributed to a block rotation.

We have determined the depth of the Curie isotherm in the United Arab Emirates (UAE) using a modified centroid method based on the fractal distribution of sources. The derived spatial coverage of Curie depths and geothermal gradients are consistent with the geothermal gradients derived from the bottom hole temperatures measured in exploration wells and reveal three NNE-SSW to NE-SW-trending regions of shallow Curie depths. These are: (1) the north-western offshore region of the UAE with Curie depths of 11-25 km; (2) in central UAE ranging from the Shah field in south-central regions of the UAE to the northern offshore region of Dubai, with Curie depths of 10-25 km, high geothermal gradients of 22.1-55.3 degrees C/km, and high heat flows of 55.3-138.3 mW/m(2); and (3) in the eastern region of the UAE from Al Ain to Dibba and the Gulf of Oman, with medium Curie depths of 25-30 km. These regions of shallow Curie depths are flanked by two N-S to NE-SW-trending regions of deeper Curie depths between 35 and 50 km with low geothermal gradients and heat flows of 11.1-15.8 degrees C/km and 27.8-39.5 mW/m(2) respectively. We interpreted these regional NE-SW trends to be related to tectonic terranes composed of magmatic arcs and microcontinental fragments that have amalgamated to form the crust beneath the UAE. In addition, many large hydrocarbon fields are located immediately above or on the margins of these shallow Curie depth zones, suggesting that the shallow Curie depth could have played a critical role in the maturation, migration, and entrapment of hydrocarbons in the UAE. Furthermore, since these zones delineate areas of high heat flow (>100 mW/m(2)) and high geothermal gradients (similar to 40 degrees C/km) they represent areas in which future geothermal exploration could be focused.

Extensive geophysical databases, covering the UK sector of the North Sea, have been used to gravity layer strip the sedimentary layers down to the base Zechstein so that the gravity response of the Carboniferous and deeper strata can be identified and structurally interpreted. To achieve this, the average bulk density grids for each layer were derived using Gardner's functions derived from well velocity and density logs. The resulting residual gravity response of each layer and the Moho response were then removed from the Free air gravity anomaly to generate the isostatic gravity response of the crust below the base Zechstein. This gravity response was used to re-evaluate the British Geological Survey interpretation over the Mid North Sea High (MNSH) and was able to identify the same crustal structures. Using the tilt derivative method, a positive gravity anomaly was found to parallel the central fracture zone that forms a northern extension of the Dowsing fault zone. This anomaly can be traced north across the MNSH with offsets coinciding with the WSW–ENE basement lineaments. To the south, the southern North Sea basin is well defined by the stratigraphic layer depth and thickness maps as well as the residual gravity maps which identify the structures associated with the low-density Carboniferous Coal Measures.

The Moho depths of the United Arab Emirate (UAE) and northern Oman mountains estimated from the gravity data assuming general local isostasy deepens from 34-38 km in the western and central areas of the UAE, and reaches 32-36 km and 40-52 km in the foreland basin and Oman-UAE mountains, respectively. To image the morphology of the basement, we performed 3D inversions of gravity and aeromagnetic data constrained by seismic and well data within the sedimentary layer. The inverted susceptibility and density models are generally consistent with each other. They both show that the basement, in most of the UAE, is covered by 8-18 km of sediments with the deepest part occurring within the foreland basin that flanks the western side of the Oman-UAE mountains. Farther west, covering the remainder of the UAE, the gravity and magnetic basement models vary significantly. The basement morphology derived from the density model probably reflects metasediments of weakly to non-magnetic basement with a broad basement high trending SE-NW from the Lekhwair high in the southeast to the northwestern offshore of the UAE that may delineate the present-day position of the flexural bulge caused by loading of the Semail ophiolite. In contrast, the basement morphology derived from the susceptibility model is both smoother and deeper from the west-central of the UAE to the western margin of the foreland basin, which could reflect a deeper magnetic crystalline basement. Moreover, the susceptibility model revealed several magnetic bodies with high susceptibilities interpreted as intra-basement blocks or igneous intrusions.

The structure and tectonic evolution of the Cretaceous rift basins of southern Egypt are poorly understood. In this study, the tectonostratigraphy of the Komombo Basin has been determined using seismic, well and biostratigraphic data. The tectonostratigraphy of the basin is compared to the Kharit, Nuqra and Beni Suef basins in Egypt as well as Muglad Basin in Sudan. The Komombo Basin is a 58 km long, 28 km wide NW-SE trending half-graben infilled with 2200 m of Berriasian-Maastrichtian sediments and overlain by 400 m of Pliocene sediments. Four Berriasian to Maastrichtian syn-rift and post-rift sequences and three Pliocene channel systems of Nile sediments have been identified. Moreover, a series of normal faults, negative flower structures, reverse faults and folds are mapped in the basin. Backstripping reveals two rift phases during the Berriasian-Barremian and Turonian-Santonian, respectively. Additionally, the tectonic subsidence curves indicate that two major unconformities have occurred during the Aptian-Albian and Maastrichtian-Pliocene, which are correlated with a basement uplift during the Albian-Cenomanian and the Oligocene-Miocene flank uplift related to the opening of the Red Sea, respectively. The rift episodes are attributed to far-field stress changes resulting from the initial opening of the South Atlantic and followed by the NW part of the African plate colliding and anticlockwise rotating into Europe. The highest beta factors (1.20-1.11) for both rift phases are found at the centre of the basin. The rift phases thinned the crust from 32.5 to 28.2 km and 31.9 km in the depocenter and the western flank of the basin. The Komombo Basin has a similar rift history, stratigraphy and structural style to the Kharit, Nuqra and Mugland basins. All of these basins witnessed two major rift phases in the Early and Late Cretaceous, whereas the Beni Suef Basin encountered strike-slip tectonic events in the Late Cretaceous.

Hydrocarbon fields in the United Arab Emirates (UAE) are related with Neoproterozoic basement highs and/or Ediacaran-Early Cambrian Hormuz salt domes. However, neither the basement nor Hormuz salt are penetrated or imaged by available well and seismic data due to thick Phanerozoic sediments. In this study, we have used the residual gravity anomaly of the sedimentary layer throughout the UAE by subtracting the gravity response of the basement structure from the isostatic residual gravity anomaly. The structure and distribution of the low-density Hormuz salt were then delineated for the first time by applying a 3D constrained layer inversion method on the residual gravity anomaly of the sedimentary layer. Well data were used to constrain this inversion from which the density of the reference model and the isosurface of the Hormuz salt were defined, whilst seismic profiles were used to qualitatively check the location, shape and depth of the domal structures. The inversion model shows that the Hormuz salt is more widespread in offshore than in onshore UAE and generally occurs within NESW to N-S trending basins. The inverted Hormuz salt model has a thickness that ranges from 1000 to 4000 m, with an average thickness of 2100 m. Moreover, the model suggests that the Hormuz, Ara (central Oman) and East Rub' Al Khali (Saudi Arabia) salt basins are most likely connected, except in regions of structural basement highs. In addition, the model reveals a low density (<= 2290 kg/m3) shallow layer (0-6000 m below the sea level) in the foreland basin, which corresponds to the Aruma and Pabdeh sequences that infill the foreland basin. Many of the offshore hydrocarbon fields in the UAE such as Zakum, Umm Shaif and Sarb are associated with Hormuz salt domes. Also, several hydrocarbon fields adjoin basement highs, which are possibly related to the flexural bulge caused by the emplacement of the Semail ophiolite on the Arabian continental margin. The basement highs are probably bordered by faults, which could have initiated halokinesis of the Hormuz salt. Thus, the 3D inverted model provides a detailed distribution of Hormuz salt bodies, which allows an improved understanding of Palaeozoic hydrocarbon plays in the UAE.

We have developed 3D inversion models derived from airborne gravity and magnetic data, which are constrained by seismic and well data, in eastern Somaliland. The density model reveals a northwest–southeast-trending basin, 125 km long and 25 km wide and called the Dood Arale Basin. The basin comprises two subbasins separated by a basement high and is infilled by up to 2500–3200 m of sediments. Smaller and shallower subbasins are also identified to the west of Lafaweyne and northeast of Dararweyne. The density model shows that the top basement in the platform areas is at approximately 1500–1700 m in depth and shallows to approximately 300 m at the Bur Anod, Hagraajin, and Hagrin Ranges and northwest of Eil Afwein. The basement depths in these areas are more uncertain and could be deeper because they occur in areas of high gravity anomalies caused by a combination of near-surface high-density sediments and high-density plutonic bodies within the basement. The susceptibility model indicates that the basement consists of very weakly magnetized metasediments of the Inda Ad Complex intruded by three northeast–southwest-trending magnetic bodies with upper surfaces at depths of approximately 300–3000 m. These magnetic bodies are interpreted as plutonic complexes of similar age and composition to the Lower Cretaceous syenite intrusions outcropping at Gorei in the Shilah Madu Range. Seismic reflection profiles image the sedimentary sequences, but they do not clearly map the top basement or detect any of the plutonic bodies. The plutonic bodies could have controlled the location of the basin’s border faults and contributed to the high geothermal gradient recorded at the Faro Hills-1 well. The Upper Cretaceous Gumburo and Jesomma Formations in the basin could potentially have reached maturation close to and above the plutonic bodies within the center of the basin.

Many seismic surveys and exploration wells have been conducted in offshore Abu Dhabi, United Arab Emirates. However, the Neoproterozoic basement and the Infracambrian Hormuz salts were not imaged or penetrated by seismic and well data. To delineate the morphology of the basement and distribution of salt bodies, we applied a 3-D constrained inversion method to aerogravity and aeromagnetic data covering offshore Abu Dhabi. Well and seismic data were used to constrain and validate the inversion results. The magnetic inversion model resulted in a robust basement model that varies in depth from 8 to 10 km with two highs at 8 and 8.5 km highlighting possibly magmatic bodies. In contrast, the gravity inversion model does not delineate very well the basement morphology, possibly due to the lower density salt bodies masking the gravity response of the higher density basement. By calculating and removing the gravity response of the magnetic basement model from the observed gravity data, we recovered the residual gravity response of the Hormuz salts. The 3-D gravity inversion of the residual shows that the Hormuz salts are more wide-spread and thicker than previously thought with a depth to top of salt varying from 5.5 to 8.5 km. This salt model suggests that the giant oilfields in offshore Abu Dhabi, such as Umm Shaif, Nasr, Abu Al-Bukhoosh, Zakum, Sarb and Hail, occur exactly above crests of salt pillows. In addition, a series of smaller oilfields are found located at the margin of the northern basement high, and three structural lineament trends (NE-SW, NW-SE, and N-S) were identified from the inverted basement and salt models. Reactivation of these fault trends and associated diapiric salt uplifts, as observed in the seismic sections and curvature map, played a major role in shaping the basement morphology and mobilization of the Hormuz salts.

There is now excellent terrestrial gravity data coverage over most of the world's continents and an even better satellite-derived gravity coverage over the oceans to allow reliable investigation of tectonic structures of continental scale. On the other hand, Terrestrial magnetic data are generally patchier in their coverage. These data types are used here in an integrated study to investigate the development of the Mesozoic West and Central African Rift System (WCARS) that split Africa in two from the Nigeria coast in the west to the Kenya coast in the east. The rift system consists of a set of interconnecting rift basins linked by shear zones that are temporally and spatially related via the Benue Trough to plate tectonic processes that formed the Atlantic Oceans. These tectonic processes are best observed in the fabric and texture of the sea-floor bathymetry and mapped using the satellite-derived free-air gravity field. The age of the sea-floor structures can be determined from the geomagnetic reversal times recorded in the oceanic rocks. These data show that the Central Atlantic Ocean plate has undergone systematic changes in plate motion that has controlled the stress field of Africa, causing periods of extension, shear and compression deformation to affect the WCARS. Crustal modelling over individual rift basins of the WCARS, using gravity and seismic data, indicates that rifting is associated with crustal thinning (necking) and isostatic subsidence and conforms to the pure shear extensional model proposed by McKenzie. The WCARS has three major phases of rift development, identified in the stratigraphic sequences contained within the rift basins. These phases of rifting are separated by major unconformities that are contemporaneous within WCARS basins and closely correlate with significant changes in flow line geometry associated with the oceanic fracture zones. Similar timed unconformities are also associated with the African continental margins, suggesting similar changes in the African stress field have caused small changes in the flexural strength of the continental margins resulting in small vertical isostatic-driven movements causing erosion and/or hiatus of sedimentation.

In the European region, the magnetic field at satellite altitudes (∼350 km) is mainly defined by a long-wavelength magnetic low, called the Central European Magnetic Low (CEML) here, located to the southwest of the Trans-European Suture Zone (TESZ). We studied this area through a joint analysis of magnetic and total gradient (∇T) anomaly maps for a range of different altitudes of 5, 100 and 350 km. Tests on synthetic models showed the usefulness of the joint analysis at various altitudes to identify reverse dipolar anomalies and to characterize areas in which magnetization is weak. This way we identified areas where either reversely or normally magnetized sources are locally dominant. At a European scale these anomalies are sparse, with a low degree of coalescence effect. The ∇T map indeed presents generally small values within the CEML area, indicating that the Paleozoic Platform is weakly magnetized. At 350 km of altitude, the TESZ effect is largely dominant: with intense ∇T highs above the East European Craton (EEC) and very small values above the Paleozoic Platform, this again denotes a weakly magnetized crust. Small coalescence effects are masked by the trend of the TESZ. Although we identified sparsely located reversely magnetized sources in the Paleozoic Platform of the CEML, the joint analysis does not support a model of a generally reversely magnetized crust. Instead, our analysis strongly favors the hypothesis that the CEML anomaly is mainly caused by a sharp contrast between the magnetic properties of the EEC and Paleozoic Platform.

The coastal and intracontinental sedimentary basins of Cameroon owe their origins to the opening of the South Atlantic. Among these sedimentary basins, we can mention those of Mamfe, Douala and Rio Del Rey, which are the subject of our current study. These were formed following geodynamic processes between the periods from the lower Cretaceous to the Neogene. These processes have significantly affected the basement of these basins leaving as consequences of multiple faults which would in their turn favor a rise of the magma towards the surface which then cooled to give birth to the volcanic rocks which exist there today. A study of the impact of the opening of the South Atlantic on the tectonics of these basins will be made from a geodynamic approach, relying in the first time on a qualitative and quantitative analysis of the anomaly map of the total magnetic intensity field reduced to the pole of each basin, then in a second time on the interpretation of the 2D geological models realized on a profile chosen on the anomaly map of the total magnetic intensity field reduced to the pole of each basin. At the end of this study, we will show that the opening of the South Atlantic has similarly impacted the structure of the three basins and the results of the spectral analysis show that the oceanic crust is thinner than the continental crust.

Free air gravity anomalies are now available from Tibetan Plateau and surrounding regions. They showthat the Plateau itself is isostatically compensated, and that its elevation is supported by its margins acting as barriers. Its interior has an elastic thickness of less than 4 km. Themain features of the Plateau can be understood by using a simple lithostatic flexural model, which can account for the paired gravity anomalies and the thrust faulting on its margins. The resulting estimates of the magnitudes of flexural forces agree with those from other observations. The thick crust that underlies the Plateau generates radiogenic heat that greatly reduces its viscosity and accounts for its weakness. As Tibet flows south over cold Indian lithosphere, heat is conducted downwards, heating up the upper mantle beneath the Moho. Combined with isostatic compensation, the resulting thermal expansion then produces a gradient in crustal thickness, from about 75 km in the south to 65 km in the north. Though this lithostatic model provides a framework for understanding many of the features of Tibet, it does not account for the difference in the dynamical behaviour between the north and south of the Plateau.

This contribution reviews the advances of gravity (including gradiometer) and magnetic methods of exploration during the last decade. The review is restricted to airborne methods of data acquisition since they are the most common method of acquisition. During this period gradiometer (FTG and AGG) methods have ‘come of age’ and both systems are providing gravity tensor data that image shallow targets as never before. This in part has been due to a significant reduction in instrument and processing noise levels. For gravity acquisition systems, their improvement in design and performance has led to better acquisition in turbulent air conditions. This now makes it possible to jointly conduct gravity and magnetic drape surveys. Improvements in processing and interpretation have gone hand in hand with improvements in acquisition. The greater use of the phase signal in the form of the tilt and local wavenumber derivatives in structural mapping, the benefits of finite depth estimation and a more stable downward continuation method are discussed.

Geologic features, such as faults, dikes, and contacts appear as lineaments in gravity and magnetic data. The automated coherent lineament analysis and selection (ACLAS) method is a new approach to automatically compare and combine sets of lineaments or edges derived from two or more existing enhancement techniques applied to the same gravity or magnetic data set. ACLAS can be applied to the results of any edge-detection algorithms and overcomes discrepancies between techniques to generate a coherent set of detected lineaments, which can be more reliably incorporated into geologic interpretation. We have determined that the method increases spatial accuracy, removes artifacts not related to real edges, increases stability, and is quick to implement and execute. The direction of lower density or susceptibility can also be automatically determined, representing, for example, the downthrown side of a fault. We have evaluated ACLAS on magnetic anomalies calculated from a simple slab model and from a synthetic continental margin model with noise added to the result. The approach helps us to identify and discount artifacts of the different techniques, although the success of the combination is limited by the appropriateness of the individual techniques and their inherent assumptions. ACLAS has been applied separately to gravity and magnetic data from the Australian North West Shelf; displaying results from the two data sets together helps in the appreciation of similarities and differences between gravity and magnetic results and indicates the application of the new approach to large-scale structural mapping. Future developments could include refinement of depth estimates for ACLAS lineaments.

The aeromagnetic data of the Mamfe Sedimentary Basin (MSB) and a part of the East of Nigeria was used to carry out the main features of that study area. To achieve this goal, we have used firstly, the horizontal gradient of the total magnetic intensity field reduced to the pole and the analytical signal of the total magnetic intensity field for the determination of the magnitude maxima of them, and finally the contacts directions deducted by Euler’s solutions. The suggested structural map of the study area presents the fault system of the zone, and the positions of the intrusions of the igneous bodies that can help in an orientation for a geophysical investigation. It also justifies the complexity of the tectonics of the region and reveals geological structures that the previous methods could not identify.

Gravity and aeromagnetic data covering the whole territory of the United Arab Emirates (UAE) have been used to evaluate both shallow and deep geological structures, in particular the depth to basement since it is not imaged by seismic data anywhere within the UAE. Thus, the aim has been to map the basement so that its structure can help to assess its control on the distribution of hydrocarbons within the UAE. Power spectrum analysis reveals gravity and magnetic signatures to have some similarities, in having two main density/susceptibility interfaces widely separated in depth such that regional-residual anomaly separation could effectively be undertaken. The upper density/susceptibility interface occurs at a depth of about 1.0km while the deeper interface varies in depth throughout the UAE. For gravity, this deeper interface is assumed to be due to the combined effect of lateral changes in density structures within the sediments and in depth of basement while for magnetics it is assumed the sediments have negligible susceptibility and the anomalies unrelated to the volcanic/magmatic bodies result from only changes in depth to basement. The power spectrum analysis over the suspect volcanic/magmatic bodies indicates they occur at ~5km depth. The finite tilt-depth and finite local wavenumber methods were used to estimate depth to source and only depths that agree to within 10% of each other were used to generate the depth to basement map. This depth to basement map, to the west of the UAE-Oman Mountains, varies in depth from 5km to in excess of 15km depth and is able to structurally account for the location of the shear structures, seen in the residual magnetic data, and the location of the volcanic/magmatic centres relative to a set of elongate N-S to NE-SW trending basement highs. The majority of oilfields in the UAE are located within these basement highs. Therefore, the hydrocarbon distribution in the UAE basin appears to be controlled by the location of the basement ridges.

We present a 3-D interpretation of the deep magnetic sources beneath the main geological structure of central-eastern Europe, the Trans-European Suture Zone (TESZ). We used a multiscale analysis of aeromagnetic data, based on a multiscale data set generated by upward continuation of the European and Mediterranean Magnetic Project data set from 5 to 100km altitude. We also computed the multiscale total gradient |delta T| of the multiscale field. Both of the multiscale data sets allow us to discriminate the main crustal contributions to the field at various scales, and we showed that at large altitudes the field is dominated by the sole effect of the TESZ. The multiridge geometric method was very useful in studying the complex features of the main crustal interfaces, either shallow or deep. The interpreted interfaces are largely agreement with geological models based on seismic surveys and, in some cases, complete the models out of the analyzed region. In order to estimate the deepest source depths in the TESZ region, we applied the multiridge method to the large scales (50-100km altitude), obtaining a set of singular points at depths ranging between 35 and 40km. Considering the heat flow trend and the geological models around the TESZ area, we found a meaningful correspondence among the location of the estimated singular points and the most abrupt variations and complex morphology features of the Moho boundary. The multiridge estimates are consistent with known structural information and can be used for a 3-D representation of the Moho depth along the TESZ.

Magnetic depth estimation methods are routinely used to map the depth of sedimentary basins by assuming that the sediments are nonmagnetic and underlain by magnetic basement rocks. Most of these methods generate basement depth estimates at discrete points. Converting these depth estimates into a grid or map form often requires the application of qualitative methods. The reason for this is twofold: first, in deeper parts of basins, there is generally a scarcity of depth estimates and those that have been determined tend to be biased toward the shallower basement structures close to the basin edge; and second, depth estimates intrinsically relate to magnetic anomalies that emanate from the top edges of basement faults/contacts resulting in a shallow depth bias. Thus, simple grid interpolation of these depth estimates often forms a shallower and structurally unrepresentative map when evaluated in detail. To overcome these problems of qualitative and/or simple grid interpolation of these point-depth estimates into a regular grid, we use the pseudogravity field transform response of the magnetic field to constrain this interpolation using inversion methods together with the relationship between the point-depth estimates and their pseudogravity values. The pseudogravity transformation converts a grid of magnetic data such that the resulting grid has the same simple relationship to magnetic susceptibility that a gravity grid has to density. The pseudogravity map is thus straightforward to visualize in terms of basement structure, but it only maps the magnetic properties of the subsurface and is not related to the gravity anomaly or the density. We describe a practical approach to invert pseudogravity grids using gravity inversion software to produce a 3D basin model assuming a constant susceptibility basement. The approach is initially tested on the Bishop 3D model and then applied to an example from the northern North Sea. This approach can be considered complementary to 3D gravity inversion and has the advantage that the pseudogravity response is not affected by structure within the sediments or effects such as sediment compaction, inversion, or isostatic compensation, all of which often complicate the gravity response of sedimentary basins.

The northern part of the Western Desert of Egypt represents the second most promising area of hydrocarbon potential after the Gulf of Suez province. An artificial neural network (ANN) approach was used to develop a new predictive model for calculation of the geothermal gradients in this region based on gravity and corrected bottom-hole temperature (BHT) data. The best training data set was obtained with an ANN architecture composed of seven neurons in the hidden layer, which made it possible to predict the geothermal gradient with satisfactory efficiency. The BHT records of 116 deep oil wells (2,000–4,500 m) were used to evaluate the geothermal resources in the northern Western Desert. Corrections were applied to the BHT data to obtain the true formation equilibrium temperatures, which can provide useful constraints on the subsurface thermal regime. On the basis of these corrected data, the thermal gradient was computed for the linear sections of the temperature-versus-depth data at each well. The calculated geothermal gradient using temperature log data was generally 30 °C/km, with a few local high geothermal gradients in the northwestern parts of the study area explained by potential local geothermal fields. The Bouguer gravity values from the study area ranged from −60 mGal in the southern parts to 120 mGal in the northern areas, and exhibited NE–SW and E–W trends associated with geological structures. Although the northern Western Desert of Egypt has low regional temperature gradients (30 °C/km), several potential local geothermal fields were found (>40 °C/km). The heat flow at each well was also computed by combining sets of temperature gradients and thermal conductivity data. Aerogravity data were used to delineate the subsurface structures and tectonic framework of the region. The result of this study is a new geothermal gradient map of the northern Western Desert developed from gravity and BHT log data.