الفهرس 
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Abstract
Wadi Budra area located at 18 km to the east of Ras Abu Rudeis town on the Gulf of Suez between longitudes 33° 20’ 53”E and 33° 21’ 30” E., latitudes 28° 52’ 55”N and 28° 53’ 34” N The study area is covered by rock exposures ranging from Precambrian to Quaternary. The Precambrian comprises granites. The Paleozoic rocks comprise five Formations from base to top: Sarabit El-Khadim, Abu-Hamata, Adadia, Um-Bogma, and Abu-Thora. The Mesozoic rocks are represented by Triassic sediments as well as Jurassic basaltic sheets and sills Besides, Post Paleozoic rocks are exposed to the south of the study area In the present study, ground geophysical studies (Gamma-ray spectrometric and magnetic) were carried out on grid lines to delineate the structural framework and to define the radiometric anomalous zones in the study areas. Beside, Self-Potential (SP) and Horizontal-Loop Electromagnetic (HLEM) surveys were selected to follow the radiometric anomalous zones at deeper depths. The main results of this study summarized as follow: 1. GAMMA-RAY SPECTROMETRY SURVEY The total-count radiometric contour map shows that, the radioactivity of the study area ranges from 1 μR/h over Wadi sediments and basaltic intrusions to 135μR/h over Um-Bogma formation. It appears that the general levels of radioactivity are controlled by the NNW to NW trends with the exposure of Um-Bogma formation, and the presence of younger granite in the southwestern part of the study area. The (eU) radiometric map of the study area can be divided into four levels. The first level changes in values from 0.1 ppm to 1.8 ppm, locates mainly in the central part over basaltic sheet and the basaltic fragments trends to the NW direction. The second level ranging from 1.8 ppm to 2.6 ppm and located at the southwestern part and some scattered parts in Abu-Thora formation. The third varying between 2.7 ppm and 4 ppm. These values recorded over wadi sediments 112 at the eastern part of study area. The fourth level (8 to 203 ppm) represents the highest values and is associated with Um-Bogma Formation, upper part of Adadia Formation and younger granite at the extreme southeastern part. The equivalent thorium (eTh) map shows that values varying from 2.1 ppm to 50.3 ppm, with an average value of about 6.5 ppm. The lowest values (1ppm to 5.1ppm) are located at the central and western parts of the study area. The intermediate values (5.1ppm to 9ppm) are located in scattered zones in Abu-Thora Formation in the western part and also in the eastern part at Wadi Sedri due to granite wash, and it`s weathering products. While, the highest values (9 to 50 ppm) recorded over the eastern parts of the study area and associated with Um-Bogma Formation, upper part of Adadia Formation and granites. The Potassium (K) map shows values varying from 0.1 % to 2.5 %, with an average value of about 0.3 %. The highest values are located at the eastern parts of the study area. Meanwhile, the lowest values are situated at the middle and western parts of the study area. Um-Bogma Formation recoded fairly high radioactivity ranges: TC (2.2-135.1 μR/h), eU (1.5-203.9 ppm) with mean value 20.88ppm, eTh (1.2-50.3 ppm) and K (0.1-3.7%). Despite the high eU/eTh mean (1.78), which reflects uranium enrichment, the mean of eU/K ratio(40.92) indicate very high U-mobilization and enrichment. Thus, this Formation is considered a promising target for uranium exploration. The radiation dose rate map shows variable intensity values, range from 0.2 to 54.8 mSv/y. By comparison with geologic map, the lowest dose rate intensity levels (≤ 0.5mS/y) were recorded over the Basalt, and Abu-Thora Formation, while the intermediate level (from 0.5 to1 mS/y) was recorded over Adadia and Eastern wadi deposits. The highest dose rate intensity levels ( ≥1 mS/y) which are considered as high levels of radiation were recorded over Um-Bogma formation, and granitic rocks. 113 2. Ground Magnetic Survey According to the visual inspection of the total magnetic map , two magnetic anomalous zones of varying magnetic characteristics were distinguished on the basis of the differences in the character of the magnetic sources generally the high anomalous zone in the west due to basaltic sheet and the low anomalous zone in the east due to the presence of younger granites. from the regional magnetic-component map the regional anomalies map show wide range of magnetic field intensity difference from -164 (nT) to -52 (nT) the acidic granite rocks is shown in the south-east part of the study area, which is characterized by smooth contours and low magnetic relief, where the two cones of basalt shown in the north-west, and south-west parts of regional aomaly map. The regional anomalies trends mainly to NNW_SSE and NW_SE directions (the Gulf of Suez direction) and the NNE_SSW directions (the Gulf of Aqapa direction) The residual magnetic component map defines the abrupt changes in the magnetic relief, describing the shallow-seated (near-surface) geologic features and/or bodies reflecting the supra-basement structures. The residual magnetic anomalies varies from -32 (nT) to 36.7 (nT). The map clearly shows several alternative negative and positive magnetic anomaly zones, which possess a general NW-SE,NNW-SSE,NNE-SSE and N-S direction . In this work, three advanced techniques were used to analyze the magnetic data as a guide for structural interpretation and basement configuration. These methods are analytic signal depth technique (AS), Euler De-convolution and Source Parameter imaging ”SPI”technique. These methods are proved as efficient tools to map the location of magnetic structures such as faults and contacts. The analytic signal depth map shows depths varies from 36.8m to 3.7 . Shallow sources are located mainly in the central part of the study area associated with basalt . These sources take N-S and NNW-SSE trends, which are the dominant structural trends in the southwestern part of Sinai. While the deep sources are located in three zones: the first zone at the southern part in Wadi deposits, the 114 second zone also associated with wadi deposits at wadi sedri , the third zone located at the northern part The Source Parameter Imaging map shows that the low depth magnetic sources locate mainly in the central part of the area ( Basaltic sheets) some shallow depths located in the eastern part (ferruginous sandstone ) and granites that exposed in the southwestern part . While deep sources locates in the southern part . depths varies from 43.1m in deep magnetic sources to 2.1m in shallow magnetic sources. Shallow sources are located mainly in the central part of the study area associated with basalt . Through the application of Euler deconvolution with structural index SI=0.0, an Euler map was derived which shows clustering of circles in linear and curved shapes indicating the nature of probable contacts between the rock units. The linear clustering circles are suggested to be the result of faults and/or contacts with depths values ranging between 1m and 43m. The solutions of depths are widely spread along the study area. These solutions trends in NW-SE, NNW-SSE, NNE-SSW, and NE-SW directions. It can deduce the main lineaments of the contacts and faults trend in the NW-SE, NNW-SSE, NNE-SSW, and NE-SW directions. The solution depths of more than 35m are mainly concentrated in the Southern part. Meanwhile, the near surface depths (< 20m) are mainly encountered at the centeral and Northwestern parts of the study area. 3. Self Potential (SP) method The constructed SP color map of the surveyed area exhibits a wide range of amplitudes varies from -98.4 to +77 mV. The high negative amplitudes (from about -27.9 to -98.4 mV) can be related to strong surface mineralizations or shallow depth to top of the ore bodies, associated with Um-Bogma formation. In terms of the scattered moderate negative SP amplitudes (-10 to -23 mV) all in the Northern East of mapped area, they can be related to ground water, as confirmed from the field observations. The relatively weak negative SP values could be related to clay or poor conductive materials within the drainage lines, while the positive SP values 115 are mainly associated with the resistant un-mineralized wadi sediments in the SP surveyed area. The obtained results from the selected SP anomalies deduced that: a) The calculated depths to centres of the selected SP anomalies are shallow, varying from 3.3 to 21.0 m and averaging about 16m. b) The half-widths of the anomalous bodies range between 8.4 m and 61 m, with a mean value of 17.2 m. c) The polarization angles (θ), which reflect the dips of the anomalies, range from 20º to 38º to North and East directions. 4. Horizontal loop Electromagnetic Method (HLEM). Line 900(E-W) The line was measured from the East to the West from station 4945to station 4535 using coil separation 50m and the station separation was 10m. The line direction is typically with UTM latitude 3195900 North passing throw wadi deposit in order to locate the best anomalous for conductive zone(in Um-Bogma formation following SP anomalies. The shape of the in-phase component reveals the conductive body has a thin width with nearly low dip (20o) to the west direction. The obtained parameters d/a =0.22 and λ/a =0.24 were gained from standard curves; the depth to surface of conductor is 11m.The thickness conductivity 18.9 mho/m. Line 280(S-N). The line was measured from the South to the North passing throw wadi sediments in order to locate the best anomalous for conductive zone and prospect the presence of mineralization at the fault plane...The shape of the in-phase component reveals the conductive body has a thin width with nearly low dip (20o) to the south direction. This depth angle was obtained from the master curves for a rapid evaluation of the dip of half-plane conductor. The obtained parameters d/a =0.42 and λ/a =0.24 were gained from curves in order to calculate depth to surface of conductor is 42m.The thickness conductivity 4.7 mho/m.