The Barud gneissic dome complex is situated along the ENE-trending dextral shear zone of the Qena-Safaga Line that serves as a significant tectonic boundary between the basement terrains of the Northern and Central Ea...The Barud gneissic dome complex is situated along the ENE-trending dextral shear zone of the Qena-Safaga Line that serves as a significant tectonic boundary between the basement terrains of the Northern and Central Eastern Desert.These terrains exhibit distinct differences in crustal composition and deformation style.The Northern Eastern Desert and its extension into Sinai are predominantly composed of gneissic granites that are intruded by large batholiths of calc-alkaline and alkaline granites.Conversely,the Central and Southern Eastern Desert are commonly blanketed by a carapace of ophiolite-bearing volcano-sedimentary rocks of the Pan-African cover nappes.These northern terrains,just north of the Barud dome complex,the crust underwent significant NW-SE regional crustal extension across the Qena-Safaga Line,which sharply delineates the northern limit of the transpressional deformations linked to the Najd fault system in the Central and Southern Eastern Desert.Through comprehensive geological mapping and the integration of various geophysical,geochemical and geochronological data,this paper offers explanations for the contrasting geological features of the basement terrains on both sides of the Qena-Safaga Line and its analogous Fatira Shear Zone that plays a significant role in tectonic modeling of the Barud dome complex region.The Barud gneissic protolith experienced crustal shortening approximately 697 million years ago in the NW-SE direction,initiating dextral motion along the Fatira Shear Zone.Large batholiths of granodiorite/tonalite complex intruded the Barud gneissic dome protolith around 630 million years ago along the Qena-Safaga Line,at relatively shallow crustal depths,following the same orientation as the earlier shortening direction.Ongoing magmatic activity along the Qena-Safaga Line indicates intense magmatic underplating,resulting in significant intrusions of granodioritic melts into the early rifted crust of the Northern Eastern Desert and Sinai terrains.The crust of these northern terrains likely underwent isostatic compensation through uplifting and subsequent erosion.The disappearance of ophiolite-bearing belts and the presence of Paleo-to Mesoproterozoic continental-derived cobbles and ignimbrites in Sinai metasedimentary belts and Northern Eastern Desert molasse basins suggest that the northern terrains,located north of the Qena-Safaga Line,originated as a cohesive,thin continental crust that rifted off the eastern passive margin of the Sahara Metacraton during the early Neoproterozoic rifting of the Rodinia supercontinent.展开更多
The Cretaceous Koum Basin is a rift-related half-graben in northern Cameroon,which constitutes a portion of the Yola Arm of the Upper Benue Trough.This study presents the first comprehensive dataset combining mineral-...The Cretaceous Koum Basin is a rift-related half-graben in northern Cameroon,which constitutes a portion of the Yola Arm of the Upper Benue Trough.This study presents the first comprehensive dataset combining mineral-ogical,bulk-rock geochemical,and stable C-H-O isotopic data for dark-gray,finegrained mudstones from the basin,providing new insights into its sediment source,paleoenvironment,and geodynamic setting.The mudstones primarily consist of phyllosilicates(~8.6%),feldspars(~30.5%),carbonates(~13.7%),and minor iron oxides(~2.7%),with vermiculite,illite,and kaolinite as the main clay minerals.The presence of analcime,ankerite,and dolomite suggests low-grade metamorphism and/or hydrothermal alteration.Fe_(2)O_(3)/K_(2)O(1.52-6.40)and SiO_(2)/Al_(2)O_(3)(2.97-4.68)ratios classify the mudstones as compositionally immature shales(ICV~1.64)with low-moderate chemical weathering(CIA~56.35;PIA~59.74;R^(3+)/R^(3+)+R^(2+)+M^(+)~0.51).Trace element ratios(Th/Sc~1.70,Zr/Sc~1.33,La/Sc~6.30,La/Th~4.14)indicate an intermediate igneous provenance from a continental crustal source.Paleoenviron-mental proxies suggest deposition in a dynamic basin environment marked by fluctuating redox(C org/P:0.21-178.34)and salinity(Sr/Ba:0.34-3.25;N-values:48-35.92)conditions,ranging from oxic to anoxic and brackish to saline.Major element data(SiO_(2) vs.Al_(2)O_(3)+K_(2)O+Na_(2)O)indicate a semi-arid regime,while Paleoclimatic indicators such as Sr/Cu(1.88-37.47)and C-values(0.12-0.93)suggests alter-nating humid and arid conditions.Notably,stable isotope data,reported here for the first time in the Koum Basin,reveal a predominantly terrestrial,fluvial-deltaic C_(3) plant source for organic carbon(δ^(13)C-25.2‰ to -35.2‰)and complex fluid-rock interactions involving meteoric and magmatic-metamorphic fluids under a warm,equatorial climate(δ^(18)O+3.6‰to +24.9‰,δ^(2)H-104‰ to-50‰).The combined mineralogical,geochemical,and isotopic data point to deposition in a tectonically active continental arc setting,with contributions from ocean island arc and passive margin sources.展开更多
Mineral deposit mapping is very essential for sustainable and eco-friendly exploitation of natural resources.The Kingdom of Saudi Arabia has abundant natural resources such as natural gas,oil and minerals.It reserves ...Mineral deposit mapping is very essential for sustainable and eco-friendly exploitation of natural resources.The Kingdom of Saudi Arabia has abundant natural resources such as natural gas,oil and minerals.It reserves high quantity of minerals such as phosphates,bauxites,copper,gold and other industrial minerals.The red soil regions located in Hail and Qassim provinces of Saudi Arabia have rich amount of bauxite(major aluminum ore)deposits.In order to initiate the focus on mapping of mineral deposits along this area,standardized hyper-spectral analysis has been carried out by using Advanced Spaceborne Thermal Emission and Reflection Radiometer(ASTER)satellite data.The spectral signature of gibbsite(major element in bauxite)samples is analyzed with reference to the spectral features of gibbsite in the visible near infrared and short-wave infrared bands electromagnetic spectrum.Advanced hyper-spectral transformations such as minimum noise fraction function and pixel purity index have been performed to identify the target end-member.The existence of the mineral is confirmed by comparing the spectral signatures of the endmember with the predefined spectral plots of ASTER and United States Geological Survey spectral libraries.Finally,the end-members are mapped and their abundance is estimated in 0–1 scale.The study has opened up new areas for mapping of bauxite deposits in the area and leads to eco-friendly exploitation of natural resources.It also validates the high potential of ASTER multispectral satellite data for the exploration and mapping of mineral resources.展开更多
The Eastern Desert of Egypt suffered a protracted period of deformation triggered by cratonization of the new juvenile crust known as the Arabian Nubian Shield(ANS),which has been proposed for potential gold discoveri...The Eastern Desert of Egypt suffered a protracted period of deformation triggered by cratonization of the new juvenile crust known as the Arabian Nubian Shield(ANS),which has been proposed for potential gold discoveries associated with the corresponding tectonic event.The Fatira area,on the border of Egypt’s Northern and Central Eastern Deserts,is covered with metavolcanic rocks twisted by a dextral relocation of the Fatira Shear Zone(FSZ)relative to the Barud magmatic body.The recent study evaluated many deformed post-orogenic granitic intrusions and felsite dikes associated with promising mineralization localities,notably orogenic gold deposits.The combination of various field observations and remote sensing data,followed by the analysis of aeromagnetic enhanced maps,allowed the differentiation of distinct lithologies,structural features,and hydrothermal alterations in the study area.Additionally,the integrated results obtained from the different interpretation techniques are utilized to identify and confirm the previously supposed mineralized localities in the Fatira and Abu Zawal areas and predict other matched localities.The final ASTER,Sentinel 2 hydrothermal alteration,and orientation entropy heat maps demonstrate the association between these mineralized regions and major structures related to the FSZ late stage of deformation rather than other structures studied throughout the area of interest.展开更多
Ca is a minor component of olivine (oliv). Its concentration measured by electron microprobe (EMP) is about 0.1—0.5%, which is close to the minimum detection limit. As Ca distribution between oliv and clinopyroxene (...Ca is a minor component of olivine (oliv). Its concentration measured by electron microprobe (EMP) is about 0.1—0.5%, which is close to the minimum detection limit. As Ca distribution between oliv and clinopyroxene (cpx)has the possibility of being used as geothermobarometers, it is very important to measure accurately the Ca content in oliv. Proton-induced X-ray emission (PIXE) technique as a new high energy analysis method shows advantage in high sensitivity and accuracy of microanalyses and begins to be展开更多
Knowledge of the trace element distributions and concentrations in main mineral phases of mantle-derived rocks is particularly useful for understanding the partial melting, depletion and enrichment processes, and meta...Knowledge of the trace element distributions and concentrations in main mineral phases of mantle-derived rocks is particularly useful for understanding the partial melting, depletion and enrichment processes, and metasomatism in the earth’s mantle. Trace element data on mantle peridotites were usually obtained with large uncertainty by neutron activation analysis in China previously. We have determined trace element concentration of 173 grains of clinopyroxene (cpx) in 50 peridotite xenoliths from different areas in China using the pro-展开更多
基金The Egyptian ministry for higher education and the Stipendium Hungaricum scholarship are thanked for funding Mohamed Badawi under the joint executive program between Hungary and Egypt.
文摘The Barud gneissic dome complex is situated along the ENE-trending dextral shear zone of the Qena-Safaga Line that serves as a significant tectonic boundary between the basement terrains of the Northern and Central Eastern Desert.These terrains exhibit distinct differences in crustal composition and deformation style.The Northern Eastern Desert and its extension into Sinai are predominantly composed of gneissic granites that are intruded by large batholiths of calc-alkaline and alkaline granites.Conversely,the Central and Southern Eastern Desert are commonly blanketed by a carapace of ophiolite-bearing volcano-sedimentary rocks of the Pan-African cover nappes.These northern terrains,just north of the Barud dome complex,the crust underwent significant NW-SE regional crustal extension across the Qena-Safaga Line,which sharply delineates the northern limit of the transpressional deformations linked to the Najd fault system in the Central and Southern Eastern Desert.Through comprehensive geological mapping and the integration of various geophysical,geochemical and geochronological data,this paper offers explanations for the contrasting geological features of the basement terrains on both sides of the Qena-Safaga Line and its analogous Fatira Shear Zone that plays a significant role in tectonic modeling of the Barud dome complex region.The Barud gneissic protolith experienced crustal shortening approximately 697 million years ago in the NW-SE direction,initiating dextral motion along the Fatira Shear Zone.Large batholiths of granodiorite/tonalite complex intruded the Barud gneissic dome protolith around 630 million years ago along the Qena-Safaga Line,at relatively shallow crustal depths,following the same orientation as the earlier shortening direction.Ongoing magmatic activity along the Qena-Safaga Line indicates intense magmatic underplating,resulting in significant intrusions of granodioritic melts into the early rifted crust of the Northern Eastern Desert and Sinai terrains.The crust of these northern terrains likely underwent isostatic compensation through uplifting and subsequent erosion.The disappearance of ophiolite-bearing belts and the presence of Paleo-to Mesoproterozoic continental-derived cobbles and ignimbrites in Sinai metasedimentary belts and Northern Eastern Desert molasse basins suggest that the northern terrains,located north of the Qena-Safaga Line,originated as a cohesive,thin continental crust that rifted off the eastern passive margin of the Sahara Metacraton during the early Neoproterozoic rifting of the Rodinia supercontinent.
文摘The Cretaceous Koum Basin is a rift-related half-graben in northern Cameroon,which constitutes a portion of the Yola Arm of the Upper Benue Trough.This study presents the first comprehensive dataset combining mineral-ogical,bulk-rock geochemical,and stable C-H-O isotopic data for dark-gray,finegrained mudstones from the basin,providing new insights into its sediment source,paleoenvironment,and geodynamic setting.The mudstones primarily consist of phyllosilicates(~8.6%),feldspars(~30.5%),carbonates(~13.7%),and minor iron oxides(~2.7%),with vermiculite,illite,and kaolinite as the main clay minerals.The presence of analcime,ankerite,and dolomite suggests low-grade metamorphism and/or hydrothermal alteration.Fe_(2)O_(3)/K_(2)O(1.52-6.40)and SiO_(2)/Al_(2)O_(3)(2.97-4.68)ratios classify the mudstones as compositionally immature shales(ICV~1.64)with low-moderate chemical weathering(CIA~56.35;PIA~59.74;R^(3+)/R^(3+)+R^(2+)+M^(+)~0.51).Trace element ratios(Th/Sc~1.70,Zr/Sc~1.33,La/Sc~6.30,La/Th~4.14)indicate an intermediate igneous provenance from a continental crustal source.Paleoenviron-mental proxies suggest deposition in a dynamic basin environment marked by fluctuating redox(C org/P:0.21-178.34)and salinity(Sr/Ba:0.34-3.25;N-values:48-35.92)conditions,ranging from oxic to anoxic and brackish to saline.Major element data(SiO_(2) vs.Al_(2)O_(3)+K_(2)O+Na_(2)O)indicate a semi-arid regime,while Paleoclimatic indicators such as Sr/Cu(1.88-37.47)and C-values(0.12-0.93)suggests alter-nating humid and arid conditions.Notably,stable isotope data,reported here for the first time in the Koum Basin,reveal a predominantly terrestrial,fluvial-deltaic C_(3) plant source for organic carbon(δ^(13)C-25.2‰ to -35.2‰)and complex fluid-rock interactions involving meteoric and magmatic-metamorphic fluids under a warm,equatorial climate(δ^(18)O+3.6‰to +24.9‰,δ^(2)H-104‰ to-50‰).The combined mineralogical,geochemical,and isotopic data point to deposition in a tectonically active continental arc setting,with contributions from ocean island arc and passive margin sources.
文摘Mineral deposit mapping is very essential for sustainable and eco-friendly exploitation of natural resources.The Kingdom of Saudi Arabia has abundant natural resources such as natural gas,oil and minerals.It reserves high quantity of minerals such as phosphates,bauxites,copper,gold and other industrial minerals.The red soil regions located in Hail and Qassim provinces of Saudi Arabia have rich amount of bauxite(major aluminum ore)deposits.In order to initiate the focus on mapping of mineral deposits along this area,standardized hyper-spectral analysis has been carried out by using Advanced Spaceborne Thermal Emission and Reflection Radiometer(ASTER)satellite data.The spectral signature of gibbsite(major element in bauxite)samples is analyzed with reference to the spectral features of gibbsite in the visible near infrared and short-wave infrared bands electromagnetic spectrum.Advanced hyper-spectral transformations such as minimum noise fraction function and pixel purity index have been performed to identify the target end-member.The existence of the mineral is confirmed by comparing the spectral signatures of the endmember with the predefined spectral plots of ASTER and United States Geological Survey spectral libraries.Finally,the end-members are mapped and their abundance is estimated in 0–1 scale.The study has opened up new areas for mapping of bauxite deposits in the area and leads to eco-friendly exploitation of natural resources.It also validates the high potential of ASTER multispectral satellite data for the exploration and mapping of mineral resources.
基金The Egyptian ministry for higher educationthe Stipendium Hungaricum scholarship are thanked for funding the first and third authors under the joint executive program between Hungary and Egypt。
文摘The Eastern Desert of Egypt suffered a protracted period of deformation triggered by cratonization of the new juvenile crust known as the Arabian Nubian Shield(ANS),which has been proposed for potential gold discoveries associated with the corresponding tectonic event.The Fatira area,on the border of Egypt’s Northern and Central Eastern Deserts,is covered with metavolcanic rocks twisted by a dextral relocation of the Fatira Shear Zone(FSZ)relative to the Barud magmatic body.The recent study evaluated many deformed post-orogenic granitic intrusions and felsite dikes associated with promising mineralization localities,notably orogenic gold deposits.The combination of various field observations and remote sensing data,followed by the analysis of aeromagnetic enhanced maps,allowed the differentiation of distinct lithologies,structural features,and hydrothermal alterations in the study area.Additionally,the integrated results obtained from the different interpretation techniques are utilized to identify and confirm the previously supposed mineralized localities in the Fatira and Abu Zawal areas and predict other matched localities.The final ASTER,Sentinel 2 hydrothermal alteration,and orientation entropy heat maps demonstrate the association between these mineralized regions and major structures related to the FSZ late stage of deformation rather than other structures studied throughout the area of interest.
文摘Ca is a minor component of olivine (oliv). Its concentration measured by electron microprobe (EMP) is about 0.1—0.5%, which is close to the minimum detection limit. As Ca distribution between oliv and clinopyroxene (cpx)has the possibility of being used as geothermobarometers, it is very important to measure accurately the Ca content in oliv. Proton-induced X-ray emission (PIXE) technique as a new high energy analysis method shows advantage in high sensitivity and accuracy of microanalyses and begins to be
文摘Knowledge of the trace element distributions and concentrations in main mineral phases of mantle-derived rocks is particularly useful for understanding the partial melting, depletion and enrichment processes, and metasomatism in the earth’s mantle. Trace element data on mantle peridotites were usually obtained with large uncertainty by neutron activation analysis in China previously. We have determined trace element concentration of 173 grains of clinopyroxene (cpx) in 50 peridotite xenoliths from different areas in China using the pro-
