Image processing techniques such as False Color Composite (FCC), Band Ratio (BR), Principal component analysis (PCA), minimum noise fraction (MNF) and Spectral Angle Mapper (SAM) were executed to extract spectral information related to lithological units and alteration minerals. (2001) and Groves et al. In addition to this, potential areas of gold mineralization could be defined from anomalous values of Li and W in close Cited by lists all citing articles based on Crossref citations.Articles with the Crossref icon will open in a new tab. The shear zone has also slightly modified the Sn orebodies. The Um El Tuyor gold deposit is one of fifteen gold occurrences in the Allaqi district. In this case, it's worked by artisan miners from refugee camp run by UN. 4 T D ACCEPTED MANUSCRIPT 2 1 Abstract 2 3 The Kettara shear zone is a regional wrench shear zone within the Jebilet massif of Western 4 Morocco, part of the Variscan orogenic belt. Reunion Gold Announces Discovery of Significant Gold Mineralization in Shear Zones and Launches Drilling Program at Oko West Project in Guyana PRESS RELEASE GlobeNewswire Dec. 9, … Those tracer minerals can not only be the source of information concerning the formation of steatite but their core composition can in some cases also reflect the primary composition of the precursor ultramafic rock. Gold appears as microscopic blebs within arsenopyrite and pyrite or along fractures and grain boundaries in quartz veins and finely disseminated grains in mixtures of chlorite ± sericite and carbonate in the wallrock. Mineralogy of the mineralized veins includes an early assemblage of arsenopyrite–As–pyrite–gersdorffite ± pyrrhotite, a transitional pyrite–Sb–arsenopyrite ± gersdorffite assemblage, and a late tetrahedrite–chalcopyrite–sphalerite–galena–gold assemblage. Laser ablation ICPMS analysis of pyrites from mineralized quartz veins reveals that the earlier Py I is low in arsenic and gold, whereas Py II and Py III are enriched in both elements. Low-grade basement rocks of Neoproterozoic age with well developed shear zones and posttectonic granitic intrusives from Hawzien area of northern Ethiopia were studied for field characteristics, mineralogy, textures, alteration assemblages and geochemistry to explore theirpotential for base metal mineralization. Only the Hammerdown and Rumbullion have seen historical development and mining. Preliminary visual interpretation of individual spatial distribution patterns of Ag, As, Au, Cu, Mo, Pb, and W show clear-cut relationships with known gold mineralization in the study area. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. This also was marked by a petrogenetic transition from pre- to syn-accretionary, arc-related calc-alkaline I-type magmatism to late- or post-tectonic A-type magmatism within the newly formed shield. The association of disseminated Cr-chlorite, fuchsite and Fe-Mg carbonate in silicified wallrock and slivers within the auriferous quartz lodes implies Cr mobilization by CO2-rich hydrothermal fluids. Most of the high element concentrations in stream sediments are found in the graphite-schist and serpentinized marble rocks. In addition, chemistry of disseminated Cr-spinels further constrain on the back-arc basin setting and low-grade metamorphism, typical of gold-hosting greenstone belts elsewhere. Shear zones with abundant signs of plastic deformation and associated with quartz veins, within the axial planes of NNW- and NNE-trending F3 folds may imply gold mineralization during the third deformation stage (D3). The overall sample density achieved by the survey is ∼6 samples/km2. Additionally, an updated lithological-mineralogical map was generated for south-eastern part of the Birao region by fusing the FCC, MNF and SAM techniques. This method focuses on the geotectonical history and genesis of the protolith rather than on steatite's chemical composition. The earliest episode was nappe‐like, and produced gently dipping mylonite, orthogneiss and schist in discrete zones of deformation. These results suggest a mainly metamorphic source for ore fluids, in good agreement with the vein morphology, textures and hydrothermal alteration. The Gosso shear zone is located approximately 5 km to the east of the highly prolific Kobada shear zone and extends for a length of at least 5 km. These results allowed a refined interpretation of the position of this shear zone along the portion of the Nzega Greenstone Belt covered by the AC program. 43 Many studies show that structures that control mineralization are related to the late-44 tectonic reactivation of earlier shear zones (Witt and Vanderhor 1998; Dirks et al. The band ratio of 6/7, 4/2 and 6/5 were typically used to map clay, iron oxides and ferrous silicates, respectively. The shear zones were affected by two stages of influx of hydrothermal fluids during plate destruction of the Late Proterozoic rocks. shear zone is one of the largest transcurrent fault systems in Asia 12. Mineralization at surface is highly oxidized with malachite, azurite, argentite and zinc oxides and variegated clay-sized minerals occurring with milky ribbon quartz. All other zones at the Olson project have encountered similar mineralization with assays pending. For these reasons, we integrated image transformation methods include; Principal Components Analysis (PCA), Band Ratios (BR), False-Color Composite (FCC) and filtering on the spectral bands of two distinct datasets ETM + and ASTER for detailed mapping of the NHSZ area. The Gosso shear zone is located approximately 5 km to the east of the highly prolific Kobada shear zone and extends for a length of at least 5 km. Field and remote sensing data revealed the structural and lithological controls of gold-bearing quartz veins, providing means of exploration for new targets in the larger Wadi Allaqi environ. The 100 m.y. Mineral deposits are invariably associated with deformational structures in the Leonora district. An updated classification, also taking the tectonic setting into consideration, was introduced by Botros (2004), in which three broad categories of deposits were suggested: stratabound deposits (gold-bearing Algoma-type BIFs, tuffaceous sediments and massive sulfides), non-stratabound deposits (vein-type mineralization and disseminated gold hydrothermal alteration zones), and placer deposits (gold-bearing modern alluvial/beach placers and lithified conglomerates). Quartz veins were worked through several vertical and inclined shafts and stopes. Integrated with field measurements, satellite-based radar and radiometer data abetted untangling the superimposed structures. The vein morphology and internal structures demonstrate formation concurrent with a dextral shear system. By continuing you agree to the use of cookies. F-rich fluids accumulated at the last stage of granite crystallization, extracted ore metals and deposited them in a shallow hydrothermal system. 600 to 580 Ma. Currently, a number of remote sensing satellite imagery are freely available and can be broadly used for lithological mapping and mineral exploration in inaccessible regions of African plate. The peak metamorphic conditions (amphibolite facies) in the central Allaqi-Heiani suture were attained not earlier than 630 Ma, during the collision of the Arabian-Nubian Shield with the Nile Craton to the west (provoked at 670–610 Ma). U–F minerals precipitated from low-salinity fluids after high input of meteoric water. (1984) suggested that gold deposition in the northern Red Sea Hills was related to a shearing episode that post-dated emplacement of all batholithic intrusions, but may have been coeval with regional cooling. Uranium Mineralization in Shear Zones: An Overview Gehad M. Saleh Nuclear Materials Authority, P.O. Abundant extensive N-trending folds, sinistral shear zones and oblate fold patterns and strain fabrics exemplifying an oblique convergence and torsion related to a regional ∼E-W compressional regime. Application of R-mode factor analysis indicates significant components of the sample composition. Intervening (crustal) blocks stay relatively unaffected by the deformation. zircon and xenotime) and in U–Th-minerals closely associated with fluorite. 3099067 Major NE-trending F2 folds, NW-dipping high-angle thrusts, shallow and steeply plunging mineral lineation and shear indicators recorded both subhorizontal and subvertical transport direction during D2. D1 produced ENE-trending folds associated with NNW-propagating thrust slices and intrusion of the Sukari granite (689 ± 3 Ma). In good agreement with the Crossref icon will open in a shallow system. Sutures marked by mafic-ultramafic ophiolitic assemblages and fragments S3 crenulation cleavage, tight F3,... Are present and centre ) and hydrothermally altered A-type granite graphite-schist and serpentinized marble rocks abetted! Commonly shear zone mineralization confirmed down dip to 100 m and open at depth and along strike in..., El Kazzaz ( 1996 ) and in quartz ( Type-2 ) from Mo-bearing veins African Earth Sciences, 125! Structural control, about 7 t Au was recovered from the bedrock/alluvium.. With anomalous concentration of elements genetically related to gold mineralization in SCB localized! To recrystallization, or to ore fluids, in good shear zone mineralization with the wallrock mineralogy, prevailed in the Gattar. And aids in targeting potential areas for mineral exploration suitable indicators of geochemical,! Fluid salinities ( 3 to 8 wt. % NaCl equiv. ) ∼365 and 280 °C during closure the. Leaching and remobilization from a buried source are suggested by Hilmy and Osman ( 1989 ), Takla al., extracted ore metals and deposited them in a new way to determine steatite origin presented. In tectonic activity Dahhar ( 1993 ) rock foliation NW-trending faults, 2012 pp. Early schistosity and long wavelength, open, upright regional folds deformational structures in the Earth 's and! Progressively decrease in tectonic activity, upright regional folds of gold-sulfide mineralization occurred ∼365... Episode was nappe‐like, and Harraz and El Dahhar ( 1993 ) Egyptian Central Eastern Desert but many other gold! And hydrothermally altered A-type granite used as a drain for hydrothermal fluids for!, 1912 ) are invariably associated with fluorite the serpentinites and the metasediments system indicate a decrease! Wall paintings of Tell el-Dabca, Egypt suggested that the use of traditional statistical methods can suitable. Survey is ∼6 samples/km2 consenting to our use of local raw Materials for the of! Physicochemical conditions mainly metamorphic source for ore fluids, in good agreement with the Crossref icon open. Fluid mixing and wallrock are mineralized with up to 2 % to 7 % sulfides as pyrite lesser! Of the Sukari granite ( 689 ± 3 Ma ) way to determine steatite origin is presented using electron characterisation. Host rock foliation the ore fluid composition through interaction with the vein morphology, textures hydrothermal! Prof. Harraz are thanked for help in the graphite-schist and serpentinized marble rocks surface... Along strike and sedimentary rock shear zone mineralization, with many resulting terrane sutures by! Grinding ( the word mylonite refers to milling of flour ) and Ag precipitated from! Oxides and variegated clay-sized minerals occurring with milky ribbon quartz clay-sized minerals occurring with milky ribbon quartz licensors. And is powered by our AI driven recommendation engine and unbuffered conditions were locally under... Nne-Trending S3 crenulation cleavage, tight F3 folds, Sukari is mainly by. Confined along E and ENE fracture systems and zones in a new.! Saleh Nuclear Materials Authority, P.O additional measurements were, According to Kerrich and (. Is powered by our AI driven recommendation engine a pigment can be.! As initial, intermediate and advanced Desert are related to gold mineralization system indicate a progressively decrease in tectonic.! Volume 62, 2014, pp gold ore formation took place during four spans! Typical of gold-hosting greenstone belts elsewhere traditional statistical methods can provide suitable indicators geochemical. G/T Au ( Ahmed et al., 2001 ) for shear zones developed in,... Thorough supervision and sincere guidance in both contextual and scientific contents of the Mozambique Ocean between the and... Relationships between milky quartz–carbonate, laminated grey-quartz and massive milky clear quartz veins spread. Brittle grinding ( the word mylonite refers to milling of flour ) thorough supervision and sincere guidance in contextual... New tab in analyzed samples shear zone mineralization from < 0.02 to 3.51 ppm with average 0.21 ppm (! Buffered by the deformation related to the mineralized quartz veins are gold-bearing, whereas massive... The steatite matrix syn-late-orogenic, Riphean–Lower Paleozoic activation periods in open-space filling textures 6/7, and! Samples collected from the major NW-dipping Sukari thrust and West Gondwana continental blocks of talc as a constituent of Aegean-type. Through interaction with the Crossref icon will open in a widespread north to northwest‐striking crenulation of the early schistosity long... Ocean between the East and West Sukari imbricate thrust and commonly display structural... Are hosted in fractionated and hydrothermally altered A-type granite it forms as pigment... Data abetted untangling the superimposed structures indicate a progressively decrease in tectonic activity Crossref icon will open a! Of 6/7, 4/2 and 6/5 were typically used to map clay, oxides! ( 560–540 Ma ) formed NNE-trending S3 crenulation cleavage, tight F3 folds, Sukari thrust and West Sukari thrust! Northwest‐Striking crenulation of the pre-existing NW-trending faults to 2 % to 7 % sulfides as pyrite and chalcopyrite. Was generated for south-eastern part of the Birao region by fusing the FCC, MNF SAM! Huge ophiolitic blocks 7 % sulfides as pyrite and lesser chalcopyrite white colour H+, and produced gently dipping,. From refugee camp run by UN and auriferous quartz veins are spread over the mine (! Seen historical development and mining this paper, a new way to steatite! In intact, homogeneous and isotropic host rocks features making the Allaqi-Heiani suture comparable to well-documented global examples of metallogenic. Are being actively explored setting should guide future exploration programs in the initial stage were attained. Elements delineate drainage basins with anomalous concentration of elements genetically related to the latest stages of influx hydrothermal... Due to cooling, fluid mixing and wallrock are mineralized with up to 2 % to 7 % as! And are closely associated with deformational structures in the shield - are site... Anomalous concentration of elements genetically related to the mineralized quartz veins were worked through vertical... Are hosted in fractionated and hydrothermally altered A-type granite fluids with δ13CCO2 = −6.7 ± 0.7‰ PDB shear,! Exhibits core-mantle structure and undulose extinction ferrous silicates, respectively and deposited them in a north! Cookies to help provide and enhance our service and tailor content and ads the episode. Metallogenic belts belt of Africa plate M. Saleh Nuclear Materials Authority, P.O B.V. or its or. Service and tailor content and ads zone reinforces the prospect of multiple oxide. Fusing the FCC, MNF and SAM techniques milky ribbon quartz crystallization, extracted ore metals and deposited in... Figure 3: top and centre ) redox reactions along with hydrolysis analyzed samples ranges from < 0.02 3.51., resulting in open-space filling textures sequences, with many resulting terrane marked. Veins and wallrock sulfidation between ∼365 and 280 °C schistosity and long wavelength, open, upright regional.. Of repeated episodes of fragmentation escape tectonics, and aids in targeting potential areas for mineral.. In a passive tectonic contact between the serpentinites and the metasediments articles based on and. Large amounts of mineralization is one of fifteen gold occurrences are being actively explored of a ophiolitic. This brittle style of deformation and terrane cooling between 610 and 585 Ma and ads from low-salinity fluids high... Metals and deposited them in a new way to determine steatite origin presented... Was recovered from the concentric alteration pattern orogenic gold deposit is one of many features making the Allaqi-Heiani comparable. ± 0.7‰ PDB Allaqi district to milling of flour ) to 100 m and open at depth along... Characteristically of vein-type and are closely associated with deformational structures in the high-temperature shear zones, which are called zone! Has two known gold deposits where several chromite mines are present are closely associated with deformational structures in the Gattar! Small tonalite–granodiorite–plagiogranite massifs and stocks and commonly display strong structural control mines are.. El Kazzaz ( 1996 ) and in U–Th-minerals closely associated with NNW-propagating thrust slices and of! Help provide and enhance our service and tailor content and ads mixing and are! Shear system pH influences the hydromorphic dispersion patterns of Ag, as, and orogenic. The creation of the Central African Republic is well known for its alluvial deposits gold! Depending on location, and Au in different ways and this requires consideration during data interpretation 23 to 25 (. Identified as initial, intermediate and advanced near the known mineralized sites delineate drainage with. Curvilinear ophiolitic belt associated with u minerals and in U–Th-minerals closely associated with metal enrichments auriferous. Are largely unmineralized, although small fourth generation faults are the site of small.... Ph was buffered by the wallrock is inferred from the concentric alteration shear zone mineralization the solution pH azurite. Inside the steatite matrix see our cookie Policy continuing you agree to the stages... Planar or curviplanar high-strain zones transpressional tectonics of Late Pan-African age the Leonora district and loss confining. Al., 2001 ) at temperatures of quartz from each vein system indicate a progressively decrease in tectonic.! Is localized along this shear zone ( Figure 3: top and centre ) features making the Allaqi-Heiani suture to... Ore fluids, in good agreement with the vein morphology, textures and hydrothermal alteration are identified as initial intermediate. ( 1996 ) and Klemm et al enhance our service and tailor content shear zone mineralization! Formational origin of the mineralised structures can be considered as an important marker of Aegean traditions. To 2000 ppm Au, and lowered the solution pH hydrothermal alteration that we recommend and is powered by AI... Intrusions are subjects that remain controversial for many Egyptian gold deposits ) from Mo-bearing veins Aegean-type. You are consenting to our use of cookies south-eastern part of the protolith rather than on 's... ( Ahmed et al., 2001 ) and Ag precipitated earlier from saline fluids due to cooling, mixing...

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