الفهرس 
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Abstract
The area under study is located in the northern part of central Eastern Desert,
Egypt. The area approximates 2358 km² and extends from latitudes 27 00’ to 27 21’N
and longitudes 32 40’ to 33 16´ 43’’ E in the central Eastern Desert, Egypt. It is
covered in its central and eastern parts by igneous basement complex of Precambrian
age, while its western part is occupied by cretaceous and Quaternary deposits. The
aeromagnetic data was compiled from surveys that have been conducted in 1983 by
the Western Geophysical Company of America (Aero Service Division).
Airborne magnetic and radiometric datasets were processed to interpret the
geology and to estimate the depth of the magnetic sources in Gabal El Juruf area and
its surroundings, central Eastern Desert, Egypt.
The study was aimed at mapping lithology, delineating structural lineaments and
their trends as well as estimating the depth to magnetic source bodies of the area. The
data processing steps involved enhancement filters such as reduction to the pole
(RTP), power spectrum, upward continuation, downward continuation, horizontal
derivatives, horizontal gradient magnitude (HGM), vertical derivatives, tilt derivative
(TD), analytical signal (AS), source parameter imaging (SPI), and Euler
deconvolution. Lineament analysis of the obtained results showed that the area is
dominated by NNW-SSE, NW-SE, & NE-SW trends and WNW-ESE, NNE-SSW, NS,
E-W, & ENE-WSW trends of less importance. Depths to magnetic sources
estimated by four different methods showed that the main depths for regional and
residual sources were 2.1 and 0.7 km respectively.On the other hand, high sensitivity airborne spectrometry survey data were useful
for mapping surface geology of the study area. The composite image technique was
applied to aeroradiometric data to facilitates the correlation and delineation of
lithologic units based on differences in the radioelements concentrations and ratios.
The method showed practical success to map the basement sedimentary contact,
delineate igneous rocks, and highlights those rock types characterized by low content
of radioelementsAeromagnetic data are used today in a wide range of applications and geological
fields including lithologic contacts tracing to locate different structures like faults,
dykes and layered complexes. In addition to studying the regional geological pattern
and the main structural features, aeromagnetic data allow in high resolution surveys
more detailed study to the shallow structures and near surface sources, which makes
magnetic data analysis an essential tool of geophysical exploration. The magnetic
anomalies can be originated from a series of changes in lithology, variations in the
magnetized body thickness, faulting, folding and topographical relief. A significant
quantity of information can be obtained from the qualitative interpretation of the
magnetic anomalies. In this sense, we can say that the value of the survey does not
finish with the primary interpretation, but rather it increases as more geology is
known (Keary and Allison, 1980There are two imaging problems that can be aided with the inclusion of
magnetic data: delineation of basement surface, and better definition of the geometry
of complex bodies. Magnetic data can be analyzed in a number of ways, with
enhanced techniques and imaging making it an increasingly valuable tool. The basic
geophysical concept behind this is that different rock types have different magnetic
responses (Sharma, 1997).The Interpretation of magnetic data is more complex than gravitational one, due
to the dipolar nature of the magnetic anomalies and also because of the
latitude/longitude dependent nature of the induced magnetic response, but in practice
magnetic data analysis may give more definite results as the magnetic response is a
result of fewer possible sources than gravitational anomalies (Sharma, 1997).On the other hand, airborne gamma-ray spectrometric data provide important
information through mapping the radioactive element characteristics of various
lithologies in complex terrains. The method provides estimates of apparent surface
concentrations of the most common naturally occurring radioactive elements,
Potassium (K), equivalent Uranium (eU), and equivalent Thorium (eTh). Additionally
the total count (TC) which gives the measure of the total radioactivity (Andrson and
Nash, 1997; Graham, and Bonham-carter, 1993; Jaques et al., 1997; charbonneau et
al., 1997).In the present study, high resolution imaging methods and feature extraction
techniques are applied to the airborne geophysical ( magnetic and spectral gamma-ray
) data collected over the study area together with available geological information
aiming to produce multiple attribute maps that can reveal the complex geological and
environmental setting of the area.1.2. Location
The area under study is located in the northern part of the central Eastern Desert,
Egypt. The area covers 2358 km² and bounded by latitudes 27 00’ to 27 21’N and
longitudes 32 40’ to 33 16´ 43’’E as shown in fig (1.1).
1.3. Climate and Vegetation
The area under study is characterized by typically arid climate; hot during
summer and cold in winter with very little rainfall and sky is clear during most of the
year. Winds are occasionally strong especially during winter. Vegetation is
represented by scarce desert plants, mainly around some water wells. The main water
wells in the area are Bir Abu Marawah and Bir Al Niqat (Stern et al., 1985).