Radiometric Anomalies Research Articles

Gamma spectrometry data suggest opportunities for mineral research in Alagoas, Brazil

This article presents the processing and quantitative interpretation outcomes of aero-gamma-spectrometric data within six regions renowned for copper and iron occurrences in Alagoas State, Brazil, situated within the geological framework of the Sergipan Orogen. The study primarily focuses on radioelement concen-tration data and its derived relationships, encompassing the creation of a ternary map and the utilization of targeting techniques to identify radiometric anomalies, such as potassium and anomalous uranium, along with the Factor F. These relationships enable the identification of behaviors associated with distinct geological models of mineralization, establishing connections between geophysical anomalies and well-known mineral occurrences. By integrating concentration information of radioelements K, Th, and U, in conjunction with geological data and existing mineralizations, the radiometric distributions of the region are thoroughly scrutinized. Radiomet-ric ratios and ternary maps serve to facilitate the identification of enrichment centers for target minerals and the observation of desirable radiometric signatures. Hydrothermal enrichment enhancement techniques unveil a more pronounced correlation between copper targets and potassium (K) anomalies, whereas iron targets ex-hibit a relationship with uranium (U) enrichment. A ternary map, amalgamating anomalous potassium, K/Th ratio, and Factor F, aids in the identification of hydrothermal alterations. Magnetic maps emphasize anomalies near significant indications, accentuating structurally advantageous contours for hydrothermal enrichment and contacts with magnetic minerals associated with iron deposits. Future exploration endeavors should accord pri-ority to these selected areas to unveil their mineral potential. Furthermore, the findings from this study offer valuable insights into the radiometric characteristics and their associations with ore deposits, thereby guiding investigations in other mineral-rich regions, always considering local geology as a vital initial datum.

Unveiling the mineral resources and structural patterns in the Middle Benue Trough: a comprehensive exploration using airborne magnetic and radiometric data

The Middle Benue Trough (MBT) in Northcentral Nigeria is a geologically significant area with vast mineral resource potential. Employing airborne magnetic and radiometric data, this study utilized the Centre for Exploration Targeting on enhanced total magnetic intensity data to reveal geologic structures, lithological units and mineralization zones. Lineaments predominantly trended in NE-SW direction, with noteworthy orientations in NNE-SSW and E-W. Radiometric anomalies correlated with distinct lithological units, pinpointing granitic gneiss, alluvium, shale, siltstone and sandstone. A magnetically concentrated and potassium-rich area indicated potential polymetallic-magnetic mineralization. The 2D model illustrated igneous intrusions influencing prevalent geologic structures, such as sediment baking and doming. Thorough analysis, including source parameter imaging, standard Euler deconvolution and 2D forward modelling, revealed sediment thicknesses below 1500 m. This research enhances understanding of the MBT’s geological features, offering valuable insights for mineral exploration and resource assessment in the region.

Radioanalytical models applied to the investigation of caesium signatures in sugar samples

The presence of anthropogenic radioisotopes in the environment may be due to inappropriate discards, nuclear tests and accidents, which requires and justifies constant monitoring to ensure the safety of nuclear applications. The radiometric analysis is a necessary condition for exporting sugar for world consumption. The investigation of 134Cs and 137Cs in a sugar matrix is required to predict radiometric anomalies. This work aimed to standardise a semi-empirical radiometric model to characterise and quantify caesium isotopes in sugar. The research was carried out with high-resolution gamma spectrometry, a non-destructive method. The results were applied to the analysis of different types of sugar for export. The models allowed us to determine with excellent resolution the minimum quantifiable activities of 0.74 Bq kg−1 and 0.48 Bq kg−1 for 134Cs and 137Cs, respectively, which are lower than 600 Bq kg−1, reference values adopted by the EU for isotopes in food.

Integrated radioactive mineralization modeling using analytical hierarchy process for airborne radiometric and remote sensing data, East Wadi Qena (EWQ), Eastern Desert, Egypt

Considering the current economic growth that Egypt is going through, it is necessary to increase research about the exploration of mineral resources. The current study is one of those studies that aim to define highly radioactive zones at East Wadi Qena area (EWQ), Eastern Desert using airborne radiometric and remote sensing data. This area is characterized by a complex geological setting which encountered multi-phases of deformation and tectonic events. Airborne radiometric data are used for identifying the presence of uranium, thorium, and potassium in the present study. Ternary composite map is important in radioelement exploration, as they reveal the source of radioactivity. In addition, semi-quantitative statistical analysis is an effective way in calculating radiometric anomalies. Moreover, processing and classification of remote sensing data are applied for valuable mapping of alteration and mineralization zones in the granitic rocks in the considered area. In this regard, radioactive potential zones (RPZ) have been evaluated using the Analytical Hierarchy Process (AHP) through geospatial analysis tools in Geographic Information System (GIS). Five spatial maps are extracted from among the dominant and contributing factors to the concentration of radioactive elements for resolving a radioactive prediction model. The results show that EWQ area is promising for radioactive minerals exploration at diverse phases of granitic rocks, unexpectedly Dokhan volcanics and metavolcanic rocks. The integration between remote sensing and airborne radiometric data can effectively expect the radioactive favorable zones in the study site that can be help for future investigations in other difficult accessible areas.

The multiscale edge detection filter applied to airborne electromagnetic data interpretation: A case study at the Rio das Velhas Greenstone Belt, Quadrilátero Ferrífero, Brazil

Potential-field edge detection filters are powerful fault detection tools in mineral exploration. The application of these filters to electromagnetic (EM) data is not as accepted as those associated with potential field data. But they may be advantageous when dealing with mineralizations associated with non-magnetic rocks. This paper introduces the multiscale edge detection filter to provide an enhanced image of fault zones when applied to apparent conductivity data. The Rio das Velhas Greenstone Belt, the studied area, hosts several gold mineralizations controlled by northwest–southeast shear zones subparallel to non-magnetic metasedimentary rocks that are typical candidates for the EM interpretation. Several northwest–southeast trending faults were highlighted in the studied area. We employed a data fusion interpretation strategy by correlating the detected EM faults with radiometric anomalies to classify high-priority spots for future exploration. We tagged four known gold deposits and new targets with similar characteristics following the proposed guidelines.

Nova Colinas, Maranhão State: A newly confirmed, complex impact structure in Brazil

AbstractThe Nova Colinas structure is an approximately 7 km wide, nearly circular feature centered at 07°09′33″S/46°06′30″W in Nova Colinas municipality in southwestern Maranhão State, Brazil. The area has been investigated for 40 yr and it has been suggested repeatedly that the structure could be of impact origin—without proof having been furnished. Magnetic anomaly maps depict the structure clearly with a strong, positive magnetic anomaly over the apparent rim zone. The central area is characterized by significant positive K and Th radiometric anomalies. Fieldwork showed that the structure has annular features along the outside and some prominent, structurally dissected hills in the interior. Thirty‐three arenite samples were collected for petrographic analysis, mostly from within the structure. Microdeformation, in the form of cataclasis; concussion fractures related to compaction, and presence of planar fractures, feather features, and planar deformation features in quartz are reported. Three samples with a multitude of quartz grains with these microdeformations were analyzed by universal stage to determine the crystallographic orientations of planar fractures and planar deformation features. The results provide robust evidence that these microdeformation features represent shock metamorphism, with low (approximately 5–10 GPa) to moderate (10–16 and 10–20 GPa) shock levels. Thus, the Nova Colinas structure is now confirmed as a bona fide meteorite impact structure. The structure is moderately eroded, as shown by the absence of stronger shock deformation. The still limited available structural geological field evidence, paired with remote sensing and geophysical data, indicates that the innermost part of the structure may have a sizable remnant of a central uplift. The Nova Colinas impact age is only poorly constrained from stratigraphic inference to an upper limit of about 200–250 Ma.

Characterization of Thorium-bearing Minerals Using Micro-XRF in Metamorphic Rocks of Harau, West Sumatera

In 1974, BATAN conducted a survey to review the potential of radioactive minerals in Harau, West Sumatra. The survey shows that there are radiometric anomalies in several locations in the area. However, the survey has not been able to show the radioactive elements and minerals found in Harau. This study aims to identify and characterize radioactive elements and minerals in Harau. To prove that detailed geological mapping, radiometric mapping with Gamma Spectrometer RS-125, and analysis using Micro-XRF "M4 Tornado Plus®". The results of geological and radiometric mapping show that there are high thorium contents in the metamorphic rocks of the Kuantan Formation reaching 2300 ppm eTh. Identification of thorium-bearing minerals using a micro-XRF instrument resulted in thorium-bearing minerals found in the Harau area are thorite (ThSiO4), yttrialite (YThSi2O7), and monazite ((Ce,Nd,Th)PO4) with thorium levels within 2.75 - 42.75% ThO2 but experiencing a significant increase in Fe. In principle, micro-XRF analysis can identify minerals well, but this analysis can be supported by other analyzes so that it can provide much more precise results. This research is expected to provide information about the occurrences of thorium-bearing minerals in Harau, West Sumatera.

A New Radiological Risk Containment Procedure in Potentially Contaminated Areas

A new radiological risk containment procedure, developed to manage the radiological risk in potentially contaminated areas, is presented here. This new methodological approach, systematically employed in sampling and site inspection activities in unknown areas from an environmental point of view, allowed the discovery of eight 226Ra orphan sources buried under the road surface, in a good state of conservation, in an industrial area of the Calabrian territory, southern Italy, and they are reported here as a case study. For workers performing sampling activities in areas for which information regarding the possible presence of contaminated material is missing, an in situ radiometric check is usually carried out as a potential radiological risk prevention, by measuring the levels of environmental radioactivity. Other than this, the procedure described in this article includes, as novelty, a series of progressive operations never carried out before all together for outdoor activities: the assessment of the presence (if any) of hot spots by recording radiometric anomalies, outdoor gamma spectrometry measurements in order to identify the radionuclides generating those anomalies, the sources unearthing activities, the management of the material found and the application of a risk containment protocol.

Structural and lithological interpretation of aero-geophysical data in parts of the Lower Benue Trough and Obudu Plateau, southeast Nigeria

High resolution airborne magnetic and radiometric data were used to map probable sites for polymetallic-magmatic hydrothermal deposits in the study area. The first and second vertical derivatives, horizontal gradient, analytic signal and tilt angle derivative were used to enhance magnetic data in order to determine the location of short wavelength anomalies, magnetic sources and geologic boundaries. Also, to understand and detect radiometric anomalies controlling mineralization in host rocks, enhancement operations involving potassium (K), equivalent thorium (Th), equivalent uranium (U) concentrations and ternary imageries were carried out. All these operations enabled the delineation of responses associated with mineralization, lithology and geologic structures. Generally, lineaments trend in the NE-SW, NNE-SSW, NW-SE and E-W directions, and serve as potential pathway for hydrothermal fluid migration and mineralization. Radiometric anomalies from spectrometric imageries are caused by felsic minerals, hydrothermal rock alterations, widespread shales, residual clay, oxides and accessory minerals that constitute regolith of the area. The coincident high magnetic and potassium intensities sites in Anambra Bain (AB), Abakaliki Anticlinorium (AA), Ikom-Mamfe Rift (IMR) and Obudu Plateau (OP) are probable sites for polymetallic-magmatic hydrothermal deposits. Generally, the joint magnetic and radiometric results were able to establish link between lithology, geologic structures and hydrothermal alteration patterns.

New insights on the Ife-Ilesha schist belt using integrated satellite, aeromagnetic and radiometric data

The present study combined analysis of satellite, aeromagnetic and radiometric data for evaluation of structural features within the Ife-Ilesha schist belt. Shuttle Radar Topographic Mission digital elevation data have been enhanced using hill-shading technique for the delineation of morphological features. The superposition of total gradient amplitude lineaments on the 3-D Euler deconvolution map revealed the trends and depth of structural features within the study region. The major trends are NE–SW, NNE–SSW, E–W and minor trends in the N–S direction, including the Ifewara shear zone that trends in the NNE–SSW. The estimated depths to the top of the sources within the shear zone varies from 90 to 200 m. Complementary analysis of the airborne radiometric data revealed that the Ifewara shear zone and adjacent regions are characterized by radiometric anomalies, indicating regional mineralization alteration zone. Generally, there is a good correlation between the satellite, radiometric, aeromagnetic maps which provides new insights and re-evaluation of structural features.

The Application of Geostatistical Analysis on Radiometric Mapping Data to Recognized the Uranium and Thorium Anomaly in West Sulawesi, Indonesia.

Mamuju Region in West Sulawesi, Indonesia is one of prospect area of uranium/thorium in Indonesia. High radiometric concentrations were located in Adang Volcanic Rocks. This formation is grouped as basaltic to intermediate rock and composed by lava, pyroclastic rocks, and tuff. Regional field radiometric mapping, including radiation dose rates, potassium, uranium, and thorium contents of soil and rock was conducted to identify the existence of radioactive minerals and prospect zones. Some radiometric anomalies are detected and probably related to hydrothermal alteration, leaching, and precipitation processes. Uranium anomaly (97,261 ppm) located in Mamuju River upstream, Botteng, Takandeang and Ahu area. The anomaly related to uranium leaching and precipitation processes in leucite basalt lava. Thorium anomaly (369,461 ppm) located in Pangasaan, Takandeang, Ahu, and Taan area. To expand this radiometric mapping, we characterized the reflectance of Landsat-8 imagery based on field measurement data. Based on circular structures identification, uranium/thorium anomaly are related to the existence of volcano vents on Adang Volcanic. Based on band rationing, high uranium contents distributed in the area with less ferromagnesian mineral, while thorium did not affect. These field based and remote sensing characterization results could be used as preliminary parameters to identify wide and detail prospects.

El Ramsa area, Southwestern Sinai, Egypt: radioactivity, mineralogy, and geochemistry studies

Um Bogma Formation represents the main target for uranium exploration at El Ramsa area. The gamma-ray spectrometric survey shows diverse measurements of radioactivity over the surveyed area, which reflects contrasting radioelement, contents for the exposed various rock types. The highest radio-spectrometric levels are located in the northeast part and scattered parts to the southwest of the study area. They are mainly associated with Um Bogma Formation. Seven uranium anomalous localities are recorded which can be used as exploration guides to explore further uranium anomalies. The highest radiometric uranium anomalies were recorded within gibbsite, carbonaceous shale, dolomite, marl, and ferruginous sandstone of Um Bogma Formation. The chemical investigations indicate enrichment in U, Cu, Mn, Cd, Ni, Zn, and Pb elements. It also reveals high uranium contents up to 640 ppm and a strong positive relation between uranium and both iron and aluminum oxides was noticed. Furthermore, high content of rare earth elements, reaching up to 5736 ppm with an average 4204 ppm, is reported in gibbsite samples. Uranium minerals such as vanuralite, sklowdowskite, and phosphuranulite were detected. The present study reveals that the source of uranium and other elements in El Ramsa area is the hydrothermal fluids which associated with the magmatic eruption during the Paleozoic events.

Origin of the Caldas Novas dome (Brazil) and its thermal water circulation

The Caldas Novas dome, a 20 × 12 km elliptical structure, with its longer axis trending NNW-SSE, was previously described as a structural window into the south-central part of the Neoproterozoic Brasília belt. The Brasília belt is the central part of the Tocantins Province, a former orogen. Hot springs, broad gravimetric and magnetic features, and a radiometric anomaly over the dome are observed. The dome aligns with the well-known Alto Paranaíba Cretaceous Igneous Province. All these observations have raised questions in the past about a possible magmatic origin of the dome. In this work, existing regional gravimetric, seismologic, magnetic, radiometric, hydro-geochemical data, as well as new isotopic data, were integrated. From the magnetic data, it is clear that a NW-SE trending linear structure is the most significant geophysical feature of the analyzed dataset. We interpret that the NW-SE trending aeromagnetic lineaments may host basaltic dikes. The interpretation is based on the occurrence of basaltic rocks in the eastern portion of the Paraná basin overlying the Brasília belt, observed outcrops of basalt in the Iporá area, and the linear features identified here. Most characteristics identified in the magnetic data are also evident in the radiometrics, and a sharp anomaly in the eTh/K and eU/K ratio map is centered on the Caldas Novas dome. Weathering related depletion of potassium over the dome is the most probable explanation for the observed radiometric anomaly. From chemical and geological evidence, the groundwater in the area likely originates from meteoric processes. The thermal spring water near the dome is associated with deep circulation in fracture systems probably related to a broad shear/fault zone. This is supported by the Cretaceous dike swarm postulated in the region, possibly emplaced into an existing fracture system. We infer that a fracture system, which would continue beyond the limits of the aero-geophysical survey, most likely accounts for the groundwater circulation and heating.

A Fast Method for Modelling A Gamma-Ray Field over Inhomogeneous Ground Sources

Designing airborne gamma-ray surveys for geological purposes, mineral prospecting, environmental applications or radioactive contamination mapping requires the optimal choice of survey parameters such as the survey altitude, line spacing and survey speed with respect to the sensitivity of the instruments employed and the presumed size and intensity of the detected anomalies. The gamma-ray field attenuates significantly with the distance from the source; being able to model gamma-ray field intensity in various detector positions can be very useful. In recent years, the use of mini-airborne UAV radiometric measurement has developed rapidly. On the one hand, the low payload capacity of UAV results in low sensitivity of the employed detectors; the possibility of increasing gamma-ray signals from low altitude surveys and low speeds on the other hand raises the demand for simulating the gamma-ray field of local inhomogeneous radiometric anomalies. The gamma-ray field modelling method introduced in this paper is based on the monoenergetic approach and discretization of geological radioactive sources utilizing a three-dimensional net of point sources. The optimal density of point sources depends on the detection altitude and the degree of inhomogeneity of the radioactive source. The designed modelling method was verified by comparing the model data with experimental data from three localities where uranium anomalies occur. The degree of conformity of the model and experimental data is acceptable and confirms the applicability of the modelling method. The paper describes a relatively fast and simple gamma-ray field modelling method that is appropriate for ground planar radioactive anomalies. The method is useful for designing survey parameters and for interpretation of detected airborne gamma-ray anomalies.

Application of Bayesian classifier to magnetic and gamma ray spectrometry data for targeting hydrocarbon microseepages

The search for new hydrocarbon resources is becoming increasingly complicated and expensive. Conventional geophysical methods, such as seismic, continue to focus on finding traps in deeper and more complex structures. To save significant amounts of both time and money, hydrocarbon microseepages may dramatically change the way we carry out hydrocarbon exploration by focusing more on searching petroleum deposits and by tracking their near-surface expressions. Hydrocarbon microseepages result in predominantly vertical long-term migration and it can be manifested with a number of near surface alterations such as formation of ferromagnetic minerals and modification of radioactive element concentrations in soil (potassium depletion and increase of the uranium concentration, in relation to the thorium content).In this study, airborne gamma ray spectrometry and magnetic data have been used in Hassi R'mel region (Algeria) to identify subtle variations in radioactive element concentrations and shallow magnetic anomalies induced by hydrocarbon microseepages. A Bayesian classification algorithm has been applied to characterize the residual magnetic and radiometric anomalies that occur above the known hydrocarbon reservoirs within the study area. Weights of evidence method was used to provide a quantitative measure of the spatial association between these anomalies and the mapped hydrocarbon accumulations. Most hydrocarbon areas were confirmed by the concurrent presence of the characteristic attributes of magnetic and radiometric anomalies, and those occurring outside the known hydrocarbon occurrences may point to yet unproven underlying hydrocarbon accumulations. The wells and drill core data, together with the blind wells available in the study area, validate the final results.

Airborne gamma-ray spectrometric data interpretation on Wadi Queih and Wadi Safaga area, Central Eastern Desert, Egypt

ABSTRACT Wadi Queih and Wadi Safaga lie in the central part of the Eastern Desert of Egypt. The airborne gamma-ray spectrometric data of the study area have been interpreted qualitatively and quantitatively and correlated with the surface lithologic units to define the anomalous uranium zones and to reveal if any association is present between the radiometric anomalies and the structural trends.The radiometric data have been treated statistically. The results revealed that the area has a wide range of radioactivity ranging from 0.1 to 23.6 Ur for the total-count (TC), 0.1 to 3.3 % for potassium (K), 0.01 to 19.1 ppm for equivalent uranium (eU), and 0.29 to 18.9 ppm for equivalent thorium (eTh). The calculated CV values for all the rock units in the study area are less than 100% for three radio-elements (K, eU, eTh), except for potassium in Thebes Formation. The younger granites and Duwi Formation have the highest radiometric values. The lowest values exist over ophiolitic metagabbro, basic metavolcanics, metasediments, serpentinites, and Umm Gheig Formation. The generated composite radio-elements and composite image maps define the locations of the high anomalous radiometric and eU zones as bright white areas. The most radioactive anomalies have NW-SE and NE-SW trends.

Application of geostatistics to complete uranium resources estimation of Rabau Hulu Sector, Kalan, West Kalimantan

Kalan is one of the focus areas for uranium exploration in West Borneo that conducted by BATAN. Situated in the central part of Kalan, previous works in Rabau Hulu Sector consisted of surface geology and radiometric anomaly mapping, trenching, drilling, logging, and conventional uranium resource estimation. Nevertheless, the complete resource estimation of the previous work was still using 2D modeling, and the latest one using 3D modeling is a method-application case study in one orebody. To increase the confidence level and completing the uranium resource estimation of all orebodies in this sector, a geostatistical estimation with 3D orebody modeling using SURPAC mine planning software was conducted in this paper. Gamma-ray log data from 32 drill holes were collected and then interpreted to obtain uranium grade-thickness data. Based on the correlation of grade-thickness data according to surface orebody orientation, the orebody 3D modeling was done. It resulted in 26 orebodies with one control system of lithology as the mineralization only taken place in the quartzite unit. This 3D model then used as a constraint for block model with 4x4x2 m block size and 0.25x0.25x0.125 m minimum block size. Block model calculation was performed using ordinary kriging which generated the kriging efficiency attribute for the determination of the resource category. Within 25 meters searching radius, the calculation resulted in 408, 480 tons of ore, while total uranium resource was 268 tons of uranium with 677 ppm average grade. There were 214 tons of uranium (79%) categorized as measured while the other 54 tons of uranium (21%) categorized as indicated.

Delineation of radiometric anomalies and conductive zones using gamma-ray spectrometric and electromagnetic methods, east Gabal El-Urf area, Northern Eastern Desert, Egypt

Ground gamma-ray spectrometric (GRS) and horizontal-loop electromagnetic (HLEM) surveys were carried out to determine the radioactive anomalous zones and to follow their lateral and vertical extensions in east Gabal (G.) El-Urf area, Northern Eastern Desert, Egypt. This area and its surroundings are mainly covered by basement rocks of Late Precambrian age, represented by quartz diorites and granite porphyry, which are intruded by pegmatites, quartz veins, and basic dykes. These rocks are traversed by dry wadis (dry valleys), which are filled by Quaternary sediments.The ground gamma-ray spectrometric data revealed that the study area possesses a wide range of radioelement concentrations, oscillating from 37 to 2164 μR/h, 0.9–170 ppm, 0.1–312 ppm, and 0.2%–7.8% for total count (TC), equivalent uranium (eU), equivalent thorium (eTh), and potassium (K), respectively. The eU composite image showed that high radioactive parts are mainly associated with the pegmatite rocks.Ground HLEM survey was performed at four frequencies (7040 Hz, 1760 Hz, 440 Hz, and 110 Hz) in the study area. The interpretation of the HLEM data indicated the presence of various conductive zones, mainly associated with pegmatite bodies. The parameters of source causative bodies, such as location, dip angle, width, and conductivity thickness were estimated for three conductive bodies. The calculated depths to the selected HLEM anomalies appear to be shallow, varying from 10 m to 22 m. All the anomalous bodies have dips ranging between 60° and 80° toward the south and west. The widths of the anomalous bodies range from medium conductors (13 m) to broad conductors (40 m or more). The conductivity thicknesses showed a wide range (1.14–72.7 Siemens), with the highest value associated with the highest eU anomaly.

English

A ground radioactivity survey report and it geological analyses are presented in this work. The survey was aimed at delineating possible zones of concentration of pegmatite intrusions, a rock whose components are useful in the in the electrical and ceramic industries among others. The survey covers longitude 12°54’-13°00’E and latitude 10°7’-10°15’N, with a total surface area of 155.52 km2. Dominant plutonic rocks in the area are coarse grained/pegmatitic granites which occur as intrusion in the metamorphic rocks (gneiss and migmatite). The survey was undertaken with a Geiger counter at station spacing of 1 min (1ežŒ) following mostly a system of grid lines. A total of 48 stations were occupied and measurements of the radiometric field variations were made. Thirteen radio-lineaments have been mapped, majority (7) align with pan African deformational direction (N-S, NE-SW). Others align in the NW and E-W directions. Some radio-lineaments correlate or align with geomorphologic features of hills and straight channel streams. Based on high radiometry and ground truthing results the northern sector of the study area is designated as a pegmatite zone. Other high radiometric zones are suggested as targets for investigation for possible pegmatite occurrences because of the economic importance of this rock. Key words: Radiometric anomalies, basement complex rocks, pegmatites, lineaments and geomorphic features.

A geophysical correlation between near-surface radioactivity and subsurface faults detected by gravity method for a region located in the western desert of Iraq

This research study deals with the processing and interpretation of the total Bouguer anomaly and the total count iso-radiation data for a region located in the western desert of Iraq. The research aims to delineate the approximate locations and the effective depth of faults and how does rocks radioactivity act nearby the faults. The graphical method adopted to separate the residual fields from regional’s, in order to be processed later by applying the horizontal gradient filter. The results displayed as maps and profile section which delineate qualitatively the approximate locations of faults and quantitatively the high radio counts and major faults effective depth within the region. The results of this study showed that the major faults within the region extend with the directions NW-SE, with effective fault depth ranges of 1.7 – 4.9 Km. High radiometric anomalies detected near or between fault locations as they detected after conducting a gravity-radiometric profile section across the region. Peaks of high radiation total counts are located over the elevated blocks which produced by faulting action. The detected faults penetrate the main groundwater aquifer in the region and this considered responsible for transporting radioactive elements to the surface over and nearby the detected fault locations to form spots of accumulated radioactive deposits.