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

2015 ◽  
Vol 12 (2) ◽  
pp. 149-160 ◽  
Author(s):  
Tharwat H. Abdel Hafeez ◽  
Mohamed A. S. Youssef ◽  
Waheed H. Mohamed

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.

Geophysics ◽  
1987 ◽  
Vol 52 (7) ◽  
pp. 839-840
Author(s):  
Kenneth Watson

In 1977, the first Special Issue on remote sensing published by Geophysics contained papers selected from two special sessions at the 45th Annual International SEG Meeting, October 12–16, 1975, in Denver, Colorado. That first Special Issue consisted of eight papers: four are primarily tutorial (image processing, spectral signatures in the visible and near infrared, microwave spectra of layered media, and factor analysis of gamma‐ray spectrometry), two involve structural interpretations with implications for mineral exploration and seismicity, and two examine multispectral reflectance data for detecting hydrothermal alteration and for uranium exploration. Although these papers indicate the importance of physical properties and models in the interpretation of remote sensing data, the studies were constrained by the instruments that collected the data and by the availability of image‐processing software. Circumstances have changed significantly in the intervening decade, as illustrated in recent review papers (Watson, 1985; Goetz et al., 1983) and demonstrated by the papers in this Special Issue.


Geophysics ◽  
1977 ◽  
Vol 42 (3) ◽  
pp. 549-559 ◽  
Author(s):  
Joseph S. Duval

The remote sensing of terrestrial gamma rays has application in geologic mapping, mineral exploration, reactor site monitoring, location of lost radioactive sources, measurement of the water equivalence of snow, and soil mapping. Although the state of the art is quite good, there is a need to reexamine the use of detectors other than thallium activated sodium iodide detectors (e.g., plastic scintillators) to improve the corrections used for altitude variations and to present the data as apparent concentrations of potassium, uranium, and thorium rather than as counts per unit of time. In an attempt to improve data analysis, the technique known as factor analysis has been applied to airborne gamma‐ray spectrometric data from a survey in South Texas. This analysis technique allows the geologist/geophysicist to perform a coordinate transformation from the four count rates [potassium (K), equivalent uranium (eU), equivalent thorium (eTh), and total count] and the three ratios, (eU/K, eU/eTh, eTh/K) to a system of three independent coordinates. These three coordinates are constrained to reproduce the total variance of the original data, and the data can be separated into groups using the criterion that similar data points have similar coordinates. The distribution of the separated groups can be mapped for comparison with other information such as the mapped geology. This map of the groups represents a synthesis of all of the radiometric data.


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