Airborne Gamma-ray Spectrometric Data Research Articles

Evaluation of the environmental and structural impacts on urban expansion using airborne geophysical data at Hurghada city, Northern Eastern Desert, Egypt.

Airborne gamma-ray spectrometric and magnetic data were processed and interpreted aiming to evaluate the environmental and structural impacts on urban expansion, Hurghada City, Northern Eastern Desert, Egypt. The eastern (coastal area), northern, and southeastern parts of the study area possess the lowest level of absorbed dose rate (ADR) and annual effective dose equivalent (AEDE), which were estimated from the airborne gamma-ray spectral data of this area. Consequently, these parts are considered as suitable sites for urban expansion from the radioactivity point of view. The relatively high level of ADR and AEDE is associated with granitic rocks, some parts of Gabir formation and recent Wadi sediments, situated at southwestern, central, and eastern parts of the study area. The ADR and AEDE of these parts are considered harmful to individuals. Airborne magnetic data were also used to detect major structures that may affect various construction projects in the study area in the future. The NNW-SSE, NW-SE, N-S, and NE-SW trends represent the common structures in the study area. The obtained results of airborne gamma-ray spectrometric and magnetic data illustrated that the urban expansion should not be constructed to the west of the ring road. However, site investigations must be carried out on this part of the study area before starting any construction projects there. The present study proved the important role of airborne gamma-ray spectrometric and magnetic surveys as useful tools to delineate the environmental and structural impacts on urban expansion.

Regolith mapping using airborne gamma-ray spectrometry in central Brazil

In deeply weathered terrains, with high geological diversity and scarce outcrops, the lateritic regolith features support mineral research. Predictive regolith mapping uses spatial modeling and airborne gamma-ray spectrometric data to locate weathered residual products, such as the ferruginous lateritic duricrusts found in tropical regions. Although the regolith materials exhibit qualitative similarities in their gamma-ray spectrometric responses in RGB (KThU) images, the Boolean and fuzzy approaches highlighted differences that allows for mapping the regolith weathering residual products on a wide geodiversity protoliths. Two inference systems were used, one identified the ferruginous lateritic duricrusts and oxisols derived from the felsic/pelitc and mafic rocks types (TP test procedures), and the other identified solely those derived exclusively from mafic rocks (TPM test procedures). Cutoff values for the conjunction eTh/K ∩ eU/K ∩ eTh ∩ K (TP-4) using Boolean logic, provided the most accurate regolith map (accuracy = 95%) among the various tests carried out and indicate that in 28.6% of the total study area, there are lateritic duricrust and oxisols relative to rocks, saprolites, mottled horizons and other soils type. The eTh cutoff value > 4.4 ppm was used to exclude mafic rocks and associated soils, and the K value < 1.3% to exclude rocks with eTh/K and eU/K values similar to the lateritic duricrusts and oxisols. For mapping the lateritic duricrusts derived exclusively from the mafic rocks the conjunction of eTh ∩ eU/K ∩ eTh/K ∩ K ∩ eU (TPM-3) fuzzified by the large membership function was the most efficient. The eU variable with values < 1.21 ppm helps improve the effectiveness of this procedure. The generated predictive map indicated that in about ∼12% (657.9 km2) of the total study area, there are lateritic duricrusts and oxisols derived from mafic rocks. Therefore, a successful method of mapping vast areas from complicated lateritic regolith mosaic derived from a large geodiversity is to apply specific plugins for data fuzzification, supported by observations from field outcrops.

Radiometric Mapping for The Identification of Hydrothermally Altered Zones Related to Gold Mineralization in Ife–Ilesa Schist Belt, Southwestern Nigeria

This study presents the interpretation of airborne gamma ray spectrometric data to delineate hydrothermally altered zones related to gold mineralization in the Ife–Ilesa Schist belt. K/eTh, Kd and F–Maps highlighting Potassic alterations related to gold mineralization were processed on the Oasis Montaj software and subsequently integrated using fuzzy logic modeling to produce the hydrothermal alteration map of the study area. The C–A fractal analysis was applied to the final hydrothermal map and was able to classify the study area into background, very low, low, moderate, high and very high alteration. These classes reflect the pervasive hydrothermal alteration style of the study area. The hydrothermally altered areas are evident on granitoids and areas proximal to it indicating that granitoids are proxies of heat source. Occurrence of active mining sites in the area agrees with the generated hydrothermal alteration map of the study area with 81% agreement. It therefore shows that radiometric method is a veritable method in mapping hydrothermal alteration areas. The use of radiometric method only cannot reliably map areas of gold mineralization as mineralization can be associated with several other processes. Hence, other methods involving geochemical and magnetic methods including GIS tools can be employed for further prospecting.

Delineation of hydrothermal alteration zones associated with mineral deposits, using remote sensing and airborne geophysics data. A case study: El-Bakriya area, Central Eastern Desert, Egypt

El-Bakriya area is situated in the Central Eastern Desert of Egypt. It includes several mineral occurrences and/or deposits. Data from remote sensing and airborne geophysics (gamma-ray and magnetic) were combined to identify the hydrothermal alteration zones and structures related to these occurrences. Various processing of ASTER satellite images revealed fifteen zones of high probability for metallic mineralizations. Airborne gamma-ray spectrometric data clarify K-enrichment zones, which are correlated geologically with the distribution of calc-alkaline, alkali feldspar granites (Younger granites), and calc-alkaline quartzdiorites to granodiorites (Older granites), as well as basement metavolcanics and metasediments. An integrated hydrothermal alteration map was constructed, based on both ASTER remote sensing and airborne gamma-ray spectrometric data. This map delineates some metallic mineral occurrences and/or deposits, which are located in the detected hydrothermal alteration zones. Besides, it displays new potential zones for mineralization, such as: Gabal (G.) El-Shalul, G. El-Bakriya, G. Siwat El-Arsha and G. Umm Bisilla. The geologic and airborne magnetic maps demonstrate five structural lineament trends of E–W, ENE–WSW, NE–SW, NW–SE, and NNW–SSE directions, which might act as pathways to transport the hydrothermal solutions in the study area.

IDENTIFICATION OF AREAS OF HIGH POTENTIAL-BEARING MINERALIZATIONS, EASTERN DESERT OF EGYPT: INSIGHTS FROM AIRBORNE GAMMA-RAY SPECTROMETRIC DATA.

A major number of mineral deposits are related to hydrothermal processes. Therefore, the mapping of the hydrothermally alteration areas, connected with mineralization, is crucial in the search for metal deposits. To achieve this purpose, areas of hydrothermal alterations are targeted by processing the airborne gamma-ray spectrometric data to detect areas enriched in potassium that may indicate the existence of potassic alteration zones, which are often associated with hydrothermal alterations accompanied by mineral deposits. Data processing and analysis were performed using the K/eTh ratio, deviation of ideal potassium (Kd) and F-parameter. Besides, determining the environmental radiation risk due to the fact that the study area contains many excavation sites for various mining materials and quarries. Hydrothermal alteration indicator maps show five known mineralizations of gold, copper, molybdenum, fluorite and wolframite, which are associated with hydrothermal processes that took place in the study area. It is possible to note the intimate correlation of mineral deposits present in areas with high potassium content. Positive correlation between the computed hydrothermal alteration indicators (K/eTh, Kd and F-parameter), shown on the ternary image map, revealed favorable high and intermediate targets for the detection of various mineral deposits in the study area. On the other hand, the estimated mean values of absorbed dose rate for all rock units were within the permissible range (28-120 nGy h-1), and the mean annual effective dose rate was below the permissible limit of 1.0mSv y-1 for these rocks.

Using of airborne gamma-ray spectrometric data to the exposure of potassic alteration -recognition of alteration relates to gold mineralization

It is well known that many mineral deposits are related to hydrothermal processes, especially auriferous deposits. In this research paper, we show how to distinguish areas that have experienced hydrothermal activity, by construing airborne gamma-ray spectrometry data, especially potassium. An indirect application of aerial gamma-ray spectrometry technique is used to detect possible minerals deposits.In this region, an airborne gamma ray survey (K, eU and eTh) was carried out, based on irregular K, “F” parameter -, and Th-normalized of the K and eU anomalies. This work exhibits the mapping of hydrothermal regions possibly showing gold mineralization and the pointing out of new geological portions for this sequence, establishing prospective criteria for regional mineral exploration.We can suggest a new exploratory target, the area that is located next to Jabal Al-Ardiya (white colour on ternary map), which is characterized by high values of F-parameter, KD%, and K/eTh. Besides, enriched areas are found scattered in the north-eastern side of the study area. As result, the airborne gamma ray spectromertic data, might be used for estimation of prospective Gold Ore zones associated with the potassium alteration."

A comprehensive study for the airborne gamma-rays spectrometry results of Gabal El-Hassnawia, Central Eastern Desert, Egypt

The present study utilizes the airborne gamma-ray spectrometric data of Gabal El-Hassnawia and its vicinity in an attempt to refine the surface geological mapping and recognize the radioelements occurrences. The statistically analysed surface lineaments derived from the Landsat image proved that they are oriented to the NW, NNW, N–S, and ENE trends. Qualitatively, the highest radiometric levels are related to the younger granites, the intermediate levels are observed over the Hammamat sediments and the acidic metavolcanics while the low levels are coinciding with the metasediments, ultramafites and basic to intermediate metavolcanics. The composite images show a good close correlation with the geologically mapped rock units. The factor analysis proved that the radiometric variables uranium (eU), potassium (K) and thorium (eTh) as well as total count (TC) are highly correlated positively with each other. Three principal factors F1, F2 and F3 are extracted from the data and their scores were used in differentiating the rock types according to their radiometric levels; consequently, nine interpreted litho-radiometric units were identified. Three types of younger granites and two types of Hammamat sediments could be distinguished among the nine units. These units are subjected to statistical treatment with the goal of identifying the uranium occurrences that exceeds X + 2S and X + 3S as targets of exploration. Accordingly, it is found that the uranium province zones are related to the three types of granite (G1, G2 and G3), the second type of Hammamat sediment (H2) and more or less the acidic metavolcanics. The uranium migration indicated that the second type of Hammamat sediment (H-2) is the only unit that the uranium is migrated in whereas; the uranium is migrated out in all other units.

Investigation of a Relation between Radiogenic Heat Production Rate (RHPR) and Land Surface Heat Temperature (LST) from Thermal Bands of ASTER and Landsat-8 (TIR-Data): Case Study of West Ras Gharib area North Eastern Desert, Egypt

In this paper, an attempt was tried to study the relation between the land surface heat temperature (LST), extracted, from the thermal emission infrared data (ASTER-TIR) and (Landsat-8-TIR) imagery and radiogenic heat production rate (RHPR) that calculated from airborne gamma-ray spectrometric data applied on west Ras Gharib area at Northeastern Desert of Egypt. The area is geologically covered mainly by Precambrian basement rocks, which are unconformably overlain by Phanerozoic sedimentary succession. The method used for extraction land surface heat temperature for both ASTER-TIR and Landsat-8-TIR images is the reference channel emissivity technique and founded as the best method comparing to others. The study results showed a relative higher RHPR threshold value reached 4.8 μW/m3. On the other hand, ASTER-TIR Land Surface Temperature (AST-LST) ranges between 27.64oC to 47.2oC and, the Landsat 8-TIR Land Surface Temperature (LS8-LST) ranges between 30.64oC to 50.68oC. Comparing all results, there were a weak relationship or to some extent parallel relation between RHPR and satellite LST; as when the value of the Y-axis is constant, there are multiple values on X-axis, so it is not possible to deduce the value of one variable in terms of the other. The poor relation is regarded to the very weak RHPR which is not enough to affect the surface heat temperature, emission that could be detected by both thermal sensors of ASTER and Landsat-8 satellite TIR data. Other factors such as: topography, wind, shading and scattering, rock moisture and density, can strongly affect the surface temperature. In conclusion, the output results could be improved in areas of very high radioelement concentrations especially 235U, and through the use of the enhanced spatial resolution of future satellite TIR imaging instruments.

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.

Uranium mobility and its implication on favourable potentiality concentration in Gabal Um-Araka area, Northern Eastern Desert, Egypt

The airborne gamma-ray spectrometric data of Um-Araka area, Northern Eastern Desert of Egypt, were treated and correlated with the geological map with the aim of searching for areas of high potentiality of uranium mineralization. Uranium migration was applied to yield leaching and deposition zones of uranium for each rock unit. The positive values (representing deposition zones) are recorded on intermediate metavolcanics, Samh Formation, alkali feldspar granites, monzogranites and Gharamul Formation. Meanwhile, negative values (representing leaching zones) are associated with acidic metavolcanics, gabbro-diorites, granodiorites and Gabir Formation, as well as Pleistocene sediments, alluvial and recent wadi sediments. Uranium favourability indices (U2) and alteration—F—parameters were calculated for the different lithologic units. Monzogranite, alkali feldspar granite and intermediate metavolcanics with Wadi sediments show relatively high values for both indicators. Meanwhile, Pleistocene sediments and Samh Formation display relatively the lowest values.

Order differences to enhance the delineation of rock units boundaries by using aerospectrometric data of Wadi Al Mushash area, Central Eastern Desert, Egypt: A new approach

The present work utilizes airborne gamma-ray spectrometric data, in a trial to refine the surface geological mapping of sedimentary rocks at Wadi Al Mushash, Central Eastern Desert of Egypt. The acquired aerospectrometric data were supported by the surface geology concerning the study area. This area is mainly covered by sedimentary rocks of Tertiary to upper Cretaceous as Nubian Sandstone Formations (Quseir Clastics and Tarif Sandstone), Duwi Phosphates Formation, Dakhla Shale Formation, Esna Shale Formation, Tarawan Formation, Thebes Formation, and Quaternary deposits. High-resolution airborne gamma-ray spectrometry can be very helpful in mapping the surface geology. The method provides estimation of the apparent surface concentrations of the most common naturally occurring radioactive elements, such as potassium (K), equivalent uranium (eU) and equivalent thorium (eTh). This work is based on the assumption that, the absolute and relative concentrations of these radioelements vary measurably and significantly with lithology. The composite image technique is used to display and simulate three parameters of the radioelements concentrations. The technique offered much in terms of lithologic discrimination, based on color differences and showed efficiency in defining areas, where different lithofacies occur within areas mapped as one continuous lithology. The Differences technique is used to delineate contacts of the rock units and the mainly structures of the study area. It is based mainly on varying in change of concentration of successive total count measurements within each line in the study area. Then, a suitable difference order is selected and matched to original measured line. Moreover, plotting the suitable order as grid and applied grid peaks on this grid. Then, these ridge grid peaks are symbolized over surface geological information and prepared radioelement composite map. This provides more detail about the surface geology, and addition more contacts occurred within original rock units. These subdivisions of rock units may be related to one formation that consists of more than one member having a different composition.

Radioactive anomalies associated with the graphite-bearing metasediments, Wadi Umm Gheig area, Central Eastern Desert, Egypt

The study area is located in the central part of the Eastern Desert of Egypt and is mainly covered by different varieties of Precambrian basement rocks represented mainly by younger and older granites, metadiorite, metavolcanics, and metasediments. The analysis and interpretation of airborne gamma-ray spectrometric survey data are essentially based on the computation of the three radioelements (U, Th, and K) favorability indices, estimation of uranium migration rate percentage, variation of eU with eTh and eU/eTh ratio, and the construction of the contour map of the (eU-eTh/3.5) in the different rock units. The highest percent of uranium migration- out or leaching rate is connected with the red and pink granites of Gebel Kadabora El-hamra, metadiorite, and red and pink granites of G. Umm Rakham (− 20.8%, − 18.57%, and − 8.45% respectively), which indicates that they could represent a major U-source bodies in the area. It was observed that the metasediments and associated graphite-bearing schists west and northwest of G. Kadabora El-hamra reflect more precipitation than the other locations around the pluton (the uranium migration rates varies between 2.59 and 30%) which mean that the graphite may have acted as a reducing agent for uranium carried in oxidizing fluids (surface meteoric water) and resulted in its precipitation. In the light of the availability of uranium source, its mobility, and graphite-bearing metasediments, the area has a good potential for the possible occurrence of uranium mineralization.

Mapping upland peat depth using airborne radiometric and lidar survey data

A method to estimate peat depth and extent is vital for accurate estimation of carbon stocks and to facilitate appropriate peatland management. Current methods for direct measurement (e.g. ground penetrating radar, probing) are labour intensive making them unfeasible for capturing spatial information at landscape extents. Attempts to model peat depths using remotely sensed data such as elevation and slope have shown promise but assume a functional relationship between current conditions and gradually accrued peat depth. Herein we combine LiDAR-derived metrics known to influence peat accumulation (elevation, slope, topographic wetness index (TWI)) with passive gamma-ray spectrometric survey data, shown to correlate with peat occurrence, to develop a novel peat depth model for Dartmoor.Total air absorbed dose rates of Thorium, Uranium and Potassium were calculated, referred to as radiometric dose. Relationships between peat depth, radiometric dose, elevation, slope and TWI were trained using 1334 peat depth measurements, a further 445 measurements were used for testing. All variables showed significant relationships with peat depth. Linear stepwise regression of natural log-transformed variables indicated that a radiometric dose and slope model had an r2 = 0.72/0.73 and RMSE 0.31/0.31 m for training/testing respectively. This model estimated an area of 158 ±101 km2 of peaty soil >0.4 m deep across the study area. Much of this area (60 km2) is overlain by grassland and therefore may have been missed if vegetation cover was used to map peat extent. Using published bulk density and carbon content values we estimated 13.1 Mt. C (8.1–21.9 Mt. C) are stored in the peaty soils within the study area. This is an increase on previous estimates due to greater modelled peat depth. The combined use of airborne gamma-ray spectrometric survey and LiDAR data provide a novel, practical and repeatable means to estimate peat depth with no a priori knowledge, at an appropriate resolution (10 m) and extent (406 km2) to facilitate management of entire peatland complexes.

Uranium migration and favourable sites of potential radioelement concentrations in Gabal Umm Hammad area, Central Eastern Desert, Egypt

Airborne gamma-ray spectrometric data, covering Gabal Umm Hammad area, near Quseir City, in the Eastern Desert of Egypt, has been utilized to identify the uranium migration path, and U, Th and K-favorability indices. The following of the uranium migration technique enabled estimation of the amount of migrated uranium, in and out of the rock units. Investigation of the Taref Formation, Nakhil Formation, Tarawan Formation and Dawi Formation shows large negative amount of uranium migration, indicating that uranium leaching is outward from the geologic body toward surrounding rock units. Moreover, calculation of the U, Th and K-favorability indices has been carried out for the various rock units to locate the rocks having the highest radioelement potentialities. The rock units that possess relatively major probability of uranium potentiality include Mu′tiq Group, weakly deformed granitic rocks, and Trachyte plugs and sheets. Meanwhile, the rock units with major potential of Th-index are Taref Formation, Quseir Formation and Dawi Formation. The rock units with major potential of K-index are Dokhan volcanic and Mu′tiq group.

Assessment of background gamma radiation levels using airborne gamma ray spectrometer data over uranium deposits, Cuddapah Basin, India – A comparative study of dose rates estimated by AGRS and PGRS

The Atomic Minerals Directorate for Exploration and Research (AMD) has conducted high-resolution airborne gamma ray spectrometer (AGRS), magnetometer and time domain electromagnetic (TDEM) surveys for uranium exploration, along the northern margins of Cuddapah Basin. The survey area includes well known uranium deposits such as Lambapur-Peddagattu, Chitrial and Koppunuru. The AGRS data collected for uranium exploration is utilised for estimating the average absorbed rates in air due to radio-elemental (potassium in %, uranium and thorium in ppm) distribution over these known deposit areas. Further, portable gamma ray spectrometer (PGRS) was used to acquire data over two nearby locations one from Lambapur deposit, and the other from known anomalous zone and subsequently average gamma dose rates were estimated. Representative in-situ rock samples were also collected from these two areas and subjected to radio-elemental concentration analysis by gamma ray spectrometer (GRS) in the laboratory and then dose rates were estimated. Analyses of these three sets of results complement one another, thereby providing a comprehensive picture of the radiation environment over these deposits. The average absorbed area wise dose rate level is estimated to be 130 ± 47 nGy h−1 in Lambapur-Peddagattu, 186 ± 77 nGy h−1 in Chitrial and 63 ± 22 nGy h−1 in Koppunuru. The obtained average dose levels are found to be higher than the world average value of 54 nGy h−1. The gamma absorbed dose rates in nGy h−1 were converted to annual effective dose rates in mSv y−1 as proposed by the United Nations Scientific Committee on the Effect of Atomic Radiation (UNSCEAR). The annual average effective dose rates for the entire surveyed area is 0.12 mSv y−1, which is much lower than the recommended limit of 1 mSv y−1 by International Commission on Radiation protection (ICRP). It may be ascertained here that the present study establishes a reference data set (baseline) in these areas to assess any changes in gamma radiation levels due to mining and milling activities in future.

The 3D inversion of airborne gamma-ray spectrometric data

We present a new method for the inversion of airborne gamma-ray spectrometric line data to a regular grid of radioelement concentration estimates on the ground. The method incorporates the height of the aircraft, the 3D terrain within the field of view of the spectrometer, the directional sensitivity of rectangular detectors, and a source model comprising vertical rectangular prisms with the same horizontal dimensions as the required grid cell size. The top of each prism is a plane surface derived from a best-fit plane to the digital elevation model of the earth’s surface within each grid cell area.The method is a significant improvement on current methods, and gives superior interpolation between flight lines. It also eliminates terrain effects that would normally remain in the data after the conventional processing of these data assuming a flat-earth model.

Boolean and fuzzy methods for identifying lateritic regoliths in the Brazilian Amazon using gamma-ray spectrometric and topographic data

Airborne gamma-ray spectrometry is relatively well understood when associated with rocks, but the response and radioelement distribution in weathered materials is less known. This work used airborne gamma-ray spectrometry and altimetry to identify domains with higher probability of occurrence of lateritic crust and dismantling products in an area located in the west of the Brazilian Amazon. Map algebra was used through the Boolean and fuzzy techniques to create predictability digital models highlighting favorable areas for the occurrence of lateritic crusts. The Index Overlay Method was used in the Boolean technique. The fuzzy technique used the fuzzy algebraic product operator, fuzzy algebraic sum operator, and fuzzy gamma operator. Both models showed good correlation between the favorability predicted and the presence of crusts in the field, however, the fuzzy model showed higher correlation and highlighted areas not identified by the Boolean model. In contrast, the Boolean model allowed the visualization of the areas related to the influence of each variable or its possible combinations individually on the final map. Thus, the identification of lateritic crusts based on mathematic models applied to altimetric and airborne gamma-ray spectrometric data is a new tool that will contribute significantly to geological mapping and to the understanding related to the response and radioelement distribution in weathered materials.

Relationships between ground and airborne gamma-ray spectrometric survey data, North Ras Millan, Southern Sinai Peninsula, Egypt

In the last decades of years, there was considerable growth in the use of airborne gamma-ray spectrometry. With this growth, there was an increasing need to standardize airborne measurements, so that they can be independent of survey parameters. Acceptable procedures were developed for converting airborne to ground gamma-ray spectrometric measurements of total-count intensity as well as, potassium, equivalent uranium and equivalent thorium concentrations, due to natural sources of radiation.The present study aims mainly to establish relationships between ground and airborne gamma-ray spectrometric data, North Ras Millan, Southern Sinai Peninsula, Egypt. The relationships between airborne and ground gamma-ray spectrometric data were deduced for the original and separated rock units in the study area. Various rocks in the study area, represented by Quaternary Wadi sediments, Cambro-Ordovician sandstones, basic dykes and granites, are shown on the detailed geologic map. The structures are displayed, which located on the detailed geologic map, are compiled from the integration of previous geophysical and surface geological studies.

Utilization of airborne gamma ray spectrometric data for geological mapping and radioactive mineral exploration of Gabel Umm Tineidba area, south eastern desert, Egypt

The present work utilizes airborne gamma ray spectrometric data in a trial to refine surface geology of igneous, metamorphic and sedimentary rocks, detect any radioactive mineralization at Gabel Umm Tineidba area South Eastern Desert, Egypt. The study area is covered by rock exposures ranging in age from the Precambrian to Quaternary. Airborne gamma ray spectrometry can be very helpful in mapping surface geology. This provides estimates of the apparent surface concentrations of the most common naturally occurring radioactive elements, such as potassium (K), equivalent uranium (eU) and equivalent thorium (eTh). This is based on the assumption that, the absolute and relative concentrations of these radioelements vary measurably and significantly with lithology. The composite image technique is used to display simultaneously three parameters of the three radioelement concentrations and their three binary ratios on one image. The technique offers much in terms of lithological discrimination, based on color differences and showed efficiency in defining areas, where different lithofacies occur within areas mapped as one continuous lithology. The integration between surface geological information and geophysical data led to detailing the surface geology and the contacts between different rock units. Significant locations or favourable areas for uranium exploration are defined, where the measurements exceed (X+2S), taking X as the arithmetic mean of eU, eU/eTh and eU/K measurements and S as the standard deviation corresponding to each variables. The study area shows the presence of fifteen relatively high uraniferous zone. In addition, the trend analysis based on the total count map and the published geological map shows that, most of the well-developed structural lineaments have NS, ENE, NNE and NNW trends.

Utilization of airborne gamma ray spectrometric data for geological mapping, radioactive mineral exploration and environmental monitoring of southeastern Aswan city, South Eastern Desert, Egypt

Utilization of airborne gamma ray spectrometric data for geological mapping, radioactive mineral exploration and environmental monitoring of southeastern Aswan city, South Eastern Desert, Egypt