Egyptian Journal of Geology最新文献

{"title":"PETROLOGY AND GEOCHEMISTRY OF UM ESH OPHIOLITE SERPENTINITES, EASTERN DESERT, EGYPT: A NEOPROTEROZOIC METAMORPHOSED SSZ MANTLE","authors":"Ayman E. Maurice","doi":"10.21608/egjg.2019.216350","DOIUrl":"https://doi.org/10.21608/egjg.2019.216350","url":null,"abstract":"The Um Esh Neoproterozoic ophiolite serpentinites, Eastern Desert of Egypt, comprise massive and foliated varieties which are composed mainly of antigorite with accessory Cr-spinel. Carbonates are variable in abundance and represented by magnesite aggregates and veinlets. The Cr-spinels are usually zoned with fresh cores or relics surrounded by ferritchromite and chromian magnetite rims. The very low TiO2 contents (<0.025 wt%) of primary Cr-spinel and the low Al2O3/SiO2 values (0.010-0.016) of serpentinite samples are consistent with residual mantle which experienced high degree of partial melting. The Al2O3 (16-25 wt%) and TiO2 (average = 0.007 wt%) contents of the primary Cr-spinel overlap those of spinels of suprasubduction zone (SSZ) and mid-oceanic ridge (MOR) peridotites. However, the Cr# (0.55-0.66) and Mg# (0.39-0.59) of the fresh Cr-spinels together with depleted nature of the Um Esh serpentinites are similar to those of modern SSZ fore-arc peridotites. Profiles along zoned Cr-spinels revealed that Cr2O3, Al2O3 and MgO abundances decreased abruptly, whereas FeO contents and Fe# (Fe/Cr+Al+Fe) increased rapidly from fresh Cr-spinel through ferritchromite to chromian magnetite, with gradual change within the individual metamorphic spinel zones. On the other hand, the variation of MnO and NiO abundances is not regular from core to rim. The dominance of antigorite and the presence of metamorphic spinel rims suggest that Um Esh serpentinites have experienced prograde metamorphism up to lower amphibolite facies under oxidizing conditions.","PeriodicalId":282322,"journal":{"name":"Egyptian Journal of Geology","volume":"6 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122957409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ON THE GEOCHEMISTRY OF AMPHIBOLITE ENCLAVES IN THE PAN-AFRICAN GNEISSES OF WADI FEIRAN, SW SINAI, EGYPT, AND THEIR RELATION TO ARC MAGMATISM","authors":"N. Shallaly, shallalynahla","doi":"10.21608/egjg.2019.216353","DOIUrl":"https://doi.org/10.21608/egjg.2019.216353","url":null,"abstract":"Geochemistry of amphibolite enclaves from the Pan-African Wadi Feiran area, SW Sinai, is presented with the aim to assess the petrogenetic characteristics of their protliths. These enclaves are concordantly enclosed in biotite, hornblende and quartzofeldspathic gneisses and schists, that overlie partially migmatized granitic gneisses. They occur as variably sized, massive to highly foliated and often strongly stretched, lenses and boudins. The studied enclaves are of magmatic origin with precursors ranging from calc-alkaline andesites to tholeiitic basalts. Rare enclaves of high-Mg appinitic monzogabbro and monzodiorite are recorded in the biotite gneisses, indicating a primary magma that was generated along a subduction zone. The geochemical characters of the studied enclaves indicate that during the Pan-African, the Wadi Feiran area constituted a back-arc continental lithosphere environment that witnessed plumesubduction interaction.","PeriodicalId":282322,"journal":{"name":"Egyptian Journal of Geology","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129058876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PETROLOGY AND PHYSICO-MECHANICAL PROPERTIES OF WADI ALLAQI ORNAMENTAL STONES, SOUTHERN EASTERN DESERT, EGYPT","authors":"Shalaby, El-Desoky, Heikal, Abdel-Rahman","doi":"10.21608/egjg.2019.216360","DOIUrl":"https://doi.org/10.21608/egjg.2019.216360","url":null,"abstract":"The present paper deals with the suitability of igneous and metamorphic rocks outcropping at Wadi Umm Ashira and Wadi Tilal Al-Qulieb northwest Wadi Allaqi, Southern Eastern Desert, Egypt, to be used as ornamental stones. The igneous rocks are represented by granites and rhyolites. Meanwhile, the metamorphic rocks include white marble and colored or dolomitic marbles. The applied basic tests include petrography, physical and mechanical (apparent density, real density, volume of open pores, open porosity, water absorption and compression strength). All of these tests were carried out according to the requirements of the European Standard (EN) standards. Based on petrography and chemical analyses, the present study discusses the effect of the chemical and mineralogical compositions as well as the crystal sizes on the physical and mechanical properties of the studied rock units. The present work recommends quarrying the igneous rocks and marbles at the northwest Wadi Allaqi, as these rocks exhibit physical and mechanical properties similar to the requirements of the standards specification for ornamental stones.","PeriodicalId":282322,"journal":{"name":"Egyptian Journal of Geology","volume":"134 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128546842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"USE OF THE GEOTHERMAL GRADIENT VARIATIONS IN ZONING OF POSTMIOCENE SEQUENCE IN THE NILE DELTA, EGYPT","authors":"A. Helaly","doi":"10.21608/egjg.2019.216327","DOIUrl":"https://doi.org/10.21608/egjg.2019.216327","url":null,"abstract":"Among the most important thermal parameters of the rocks and their composing minerals is the Geothermal Gradient. Geothermal gradient plays an important role in expressing the subsurface thermal conditions in any area. After carrying out the required corrections for the thermal data in hand, it was used for estimating and illustrating the Geothermal Gradient variations with depth. Using such results, an attempt was carried out to use such variations to identify the subsurface lithologic compositional variations in the study area based on the thermal characteristics of the different subsurface lithologies.Four main subsurface units were identified and mapped within the Nile Delta.","PeriodicalId":282322,"journal":{"name":"Egyptian Journal of Geology","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124745016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"THE SUBSURFACE GEOLOGY AND RESERVOIR CHARACTERISTICS OF THE UPPER BAHARIYA RESERVOIR IN THE HAYAT/YASSER OIL FIELD, NORTHWESTERN DESERT, EGYPT","authors":"A. Khadrah","doi":"10.21608/egjg.2019.216331","DOIUrl":"https://doi.org/10.21608/egjg.2019.216331","url":null,"abstract":"The litho-stratigraphic cross sections, thickness variations and lithofacies of the Upper Bahariya reservoir (Upper Bahariya Member) are discussed to distinguish the shape, the extent of sedimentary basins and the environment of deposition. The studied Upper Bahariya reservoir shows that the Upper Bahariya Member top is coming higher at Yasser-06 well than the other three wells, which lies in the northeastern part of the study area. Furthermore, the maximum thickness of the Bahariya Formation occurs at Hayat-12, while the minimum thickness occurs at Hayat-17 well. The facies triangle lithologic model of the Upper Bahariya Member shows, the predominance of calcareous shale facies in most of the studied wells which change to shaley sand in the central part at Hayat-12 and Hayat-14 wells. These facies reflect a shallow marine environment grading from tidal-dominated estuarine channels to wave-dominated shoreline associating with lagoons or bays. The petrographic analysis shows that, there is a variation in the reservoir quality based on the detrital clay components and diagenetic processes.","PeriodicalId":282322,"journal":{"name":"Egyptian Journal of Geology","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133385387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"THE LITHOLOGICAL AND STRUCTURAL FEATURES CONTROLLING THE RADIOACTIVE MINERALIZATIONS IN YOUNGER GRANITES OF UM GURUF AREA, NORTH EASTERN DESERT, EGYPT","authors":"El Sundoly","doi":"10.21608/egjg.2019.216345","DOIUrl":"https://doi.org/10.21608/egjg.2019.216345","url":null,"abstract":"Um Guruf area in the North Eastern Desert (NED) includes granodiorite, Dokhan volcanics, Hammamat sedimentary rocks, younger granites and post granite dykes. The study area is subjected to four main sets of joints trending NE-SW, ENE-WSW, E-W and N-S. All joints in the area are of tension stress. The main faults are of NW-SE, NNW-SSE and NE-SW trends based on their number proportion. All faults in the area are of compression stress. NE-SW trend is the master trend controlling the structural and tectonic framework of Um Guruf area followed by ENE-WSW trend. The younger granites show higher radioactivity than that of the other rock types. Radioactive anomaly is recorded in zoned pegmatite pocket in Hmrat El Sorwhyia alkali feldspar granites. It contains U and Th-bearing minerals of uranophane, thorite and zircon in addition to apatite, sphene and iron oxides which capture U and/or Th elements. The radioactive anomaly is structurally controlled by two strongly hematized and silicified joints striking NNE-SSW and NW-SE and two faults trending NNW-SSE and WNW-ESE.","PeriodicalId":282322,"journal":{"name":"Egyptian Journal of Geology","volume":"68 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133454222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SHAPING BURIED BEDROCK TOPOGRAPHY USING RESISTIVITY AND GRAVITY DATA IN WADI ALLAQI, EASTERN DESERT, EGYPT","authors":"A. Helaly","doi":"10.21608/egjg.2019.216328","DOIUrl":"https://doi.org/10.21608/egjg.2019.216328","url":null,"abstract":"Vertical electrical resistivity and Bouguer gravity data were assessed at Wadi Allaqi area, Eastern Desert, Egypt aiming at the configuration of the bedrock (basement) surface, potential of groundwater availability and assessment ofthe best locations for drilling groundwater boreholes. The results obtained from geoelectrical resistivity interpretation have shown that the interpreted depths of basement surface range from about five m to sixty m with three main deeper troughs considered as best locations for groundwater accumulation and suitable for drilling of groundwater boreholes. Since, the gravity anomaly magnitude is mainly controlled by the depth to the subsurface causative feature (basement) and its density contrast with overburden. Many trials for estimating the depth at varying density contrasts (0.1-1.0 gm/cm) were done. It is found that the closest depths from the gravity analysis to the obtained resistivity analysis are the ones that were computed using the density contrast of 0.2 gm/cm as an optimum value. Finally, re-mapping bedrock topography based on that optimum value was achieved.","PeriodicalId":282322,"journal":{"name":"Egyptian Journal of Geology","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114742718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"DISCRIMINATION OF LESS AND HIGH FRACTIONATED GRANITIC ROCKS, BY WEATHERING SCHEME, BIRIRIG AREA, CENTRAL EASTERN DESERT, EGYPT.","authors":"A. Wahab","doi":"10.21608/egjg.2019.216354","DOIUrl":"https://doi.org/10.21608/egjg.2019.216354","url":null,"abstract":"The granitic rocks in Egypt cover more than 40% of the total area of the basement rocks, many efforts were exerted aiming to classify the granitic rocks in Egypt. The present work classifies the Biririg granitic rocks, in the central Eastern Desert of Egypt, on the basis of their mineralogical and chemical composition and discusses the effects of different grades of weathering on their mineralogical and geochemical characteristic. Geochemically, the Biririg granitic rocks (BGR) were derived from calc-alkaline peraluminous parental melts as revealed from agpaitic index, modified alkali-lime index and the aluminum saturation index. Based on geochemical characteristic, the BGR are classified into less fractionated pinkish white granite (LFG) mainly hornblende biotite granite, and highly fractionated pink granite (HFG) mainly biotite granite, the later is evolved, through fractional crystallization from more basic and calcic melts. The BGR were evolved at active continental margin regime, as the geochemical characteristics of the BGR exhibit three main sources of enrichments namely subduction zone, convicted mantle wedge and sub-continental lithosphere. This research discusses, further, the relation between grade of weathering and engineering-pathological properties of the granitic rocks exposed in Biririg area. The chemical index of alteration (CIA) values revealed that, both of LFG and HFG are low weathered, with slight increase of weathering towards the less fractionated pinkish white granite. The pinkish white granite is more basic than pink granite, as the former exhibits more mafic constituents represent about 8% of the total rock volume and are mainly biotite with less frequent amounts of hornblende. The BGR were classified into WI and WII according to the grade of weathering, where the mineralogical, chemical and engineering properties changed. Most elements redistribute in their newly formed secondary minerals. The differences observed in the composition of the WII samples relative to the slightly weathered WI ones, could be attributed to the fractional crystallization of melt, original magmatic features and/or crustal contamination.","PeriodicalId":282322,"journal":{"name":"Egyptian Journal of Geology","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133907143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ORGANIC GEOCHEMISTRY OF PALEOCENE – MIDDLE MIOCENE SUCCESSION, EE85-1A WELL, RAS BUDRAN, SUEZ GULF, EGYPT","authors":"Khaled, A. N.A., Helwan","doi":"10.21608/egjg.2019.216334","DOIUrl":"https://doi.org/10.21608/egjg.2019.216334","url":null,"abstract":"Ras Budran area is located in the central eastern offshore area of the Suez Gulf. The sedimentary successions from the Paleocene to the Lower-Middle Miocene were chosen to assess in the well EE85-1A at the Ras Budran area.Thegeochemical analysis of the Rock-Eval and vitrinite reflectance was applied for evaluating the studied Formations from the viewpoints of the petroleum systems. From which fifty-four cutting samples represented six Formations of Esna Shale (Paleocene), Thebes (Lower-Middle Eocene), Darat (Upper Eocene), Nukhul, Rudeis (Lower Miocene), and Kareem (Lower-Middle Miocene) were analyzed. The present study distinguishes three different categories of petroleum source potential. The first is very good to excellent source of Thebes Formation has 3.2 wt, % TOC and 22.1 mg HC/g rock of Production yield (Py=S1+S2) on averages. The second is fair sources of the Nukhul, the Darat, and the Esna Shale Formations of averages 1.23, 1.6 and 0.85 wt, % TOC and 1.67, 3.12 and 1.8 mg HC/g rock of Production yield respectively. The third is a poor source of both the Kareem and the Rudeis Formations of averages 1.4, and 0.95 wt, % TOC and 1.5, and 0.92 mg HC/g rock Py. The kerogen types of oil-prone (Type I) and mixed oil/gas prone (Type II) are the main OM (organic matter) constituent of the Thebes Formation of HI (hydrogen index) > 400 mg HC/g TOC and S2/S3 ratio is 6.97 mg HC/g rock on average. The results are categorized the Thebes Formation to be an effective source rock if buried enough to reach the oil window zone. The other Formations of Kareem, Rudeis, Nukhul, Darat, and Esna Shale include kerogens of gas prone (types III) and inert (Type IV) of HI (hydrogen index) < 200 mg HC/g TOC and S2/S3 ratio < 2 mg HC/g rock too.","PeriodicalId":282322,"journal":{"name":"Egyptian Journal of Geology","volume":"379 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126725645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MONQAR EL SANAB-MONQAR EL RAML SILICA SAND, QARAT SOMARAH REGION, EGYPT: ECONOMIC POTENTIAL AND SOME FORM OF PROCESSING TECHNIQUES","authors":"Hassaan","doi":"10.21608/egjg.2019.216362","DOIUrl":"https://doi.org/10.21608/egjg.2019.216362","url":null,"abstract":"Monqar El-Sanab Monqar El-Raml area is located 50 km SSW El-Hammam city, Northern Western Desert between latitudes 30°26'30\" and 30°20'00\"N. and longitudes 29°09\"00\" and 29°22\"30\" E. The composite stratigraphic succession of the Early Miocene Moghra Formation includes exposed very compact and consolidated ferruginous sandstones, calcareous silica sand and silica sand beds 19.5m thick and greyish black clay and shale bed 1.5m thick at its top. Silica sand is essential raw materials for glassmaking, industrial, horticultural, leisure and foundry casting applications. The study aims at undertaking investigations on the silica sand geologic features, grain size, chemical composition, easy remove of deleterious impurities, together with the level of friable sand some required form of processing technique to conform very closely to the standard specifications, and consistency in quality suitable for economic applications. The silica sand beds are sited at the top of southwards moderate sloping to the base of the succession. The consolidated and very compact ferruginous sandstones comprise calcareous quartz arenite and ferruginous calcareous quartz arenite. Both consist chiefly of >90% quartz, fine to coarse, rounded to sub-angular occasionally fractured grains (>95wt. % silica). The SiO2 discriminates three Grades I, II, III: > 98, < 98 > 97, < 97> 95 wt. % and as well, Al2O3 and Fe2O3 contents: 0.35 0.14, 1.710.3; 0.80.2, 2.3-1.71; and 1.840.4, 2.3 1.71 wt. % respectively. The 3 grades record highest wt. % of the size <600 μm >106 μm to be considered suitable for upgrading the sand. Exceptional samples of Grades I, II exist where the sizes >600 μm possess high wt. % to recommend combination of these size classes > 600 μm of the sand from the sites of such samples on exploitation. The washing of the sizes <600 μm >106 μm produced sharp decrease of Fe2O3, CaO content of the three grades (times 0.39, 0.32, 0.18 and 0.46, 0.35, 0.016). Loss on washing with water is 6.4, 1.8, 16.0 kg/ton and with 2 and 5% HCl solution 6.4, 1.8, 16.0 kg/ton to be considered an approach of suitable upgrading.","PeriodicalId":282322,"journal":{"name":"Egyptian Journal of Geology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126621080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}