Higher grade gold mineralization confirmed down dip to 100 m and open at depthand along strike. Wetait, Mehanna) and Prof. Harraz are thanked for help in the first. The Muddy Shag, Hammerdown and Rumbullion are essentially one mineralized system contained in separate faulted blocks and is collectively referred to has the Hammerdown deposit, while the Orion deposit is located approximately 2 kilometers to the southwest. Groundwater pH influences the hydromorphic dispersion patterns of Ag, As, and Au in different ways and this requires consideration during data interpretation. Bedrock was not reached in all zones along this trench and intermittent lower grade sections relate to samples collected from the bedrock/alluvium transitional. Genetically related Mo–Bi–Ag and U–F mineralization in A-type granite, Gabal Gattar, Eastern Desert, Egypt, Structural and litho-tectonic controls on Neoproterozoic base metal sulfide and gold mineralization in North Hamisana shear zone, South Eastern Desert, Egypt: The integrated field, structural, Landsat 7 ETM, Transpressional imbricate thrust zones controlling gold mineralization in the Central Eastern Desert of Egypt, Multi-element association analysis of stream sediment geochemistry data for predicting gold deposits in Barramiya gold mine, Eastern Desert, Egypt, Au and Cr mobilization through metasomatism: Microchemical evidence from ore-bearing listvenite, South Eastern Desert of Egypt, Greenstone-hosted lode-gold mineralization at Dungash mine, Eastern Desert, Egypt. Microthermometric measurements were obtained on a Linkam THM 600 heating/freezing stage, fitted with a thermal control unit TMS-93 and equipped with a binocular Olympus microscope at the Institute of Applied Mineralogy and Geochemistry, TU Munich. Sukari granite intruded in different pluses between 689 and 540 Ma and associated with at least four phases of quartz veins with different geometry and orientation. The shear zones were affected by two stages of influx of hydrothermal fluids during plate destruction of the Late Proterozoic rocks. The amount of movement along the shear zones in the main area of mineralization cannot be readily determined because of lack of markers in the wallrocks. D3 (560–540 Ma) formed NNE-trending S3 crenulation cleavage, tight F3 folds, Sukari Thrust and West Sukari imbricate thrust. The high grade of gold mineralization in Sukari is mainly controlled by SE-dipping back-thrusts branched from the major NW-dipping Sukari Thrust. Regional northwest‐striking strike‐slip faults, dominated by the sinistral Mt George shear zone, with an attendant cleavage and sub‐horizontal stretching lineation, are the product of a third episode of deformation. Register to receive personalised research and resources by email, An International Geoscience Journal of the Geological Society of Australia, Shear zones, gold mineralization and structural history in the Leonora district, Eastern Goldfields Province, Western Australia, Geology & Geophysics , Bureau of Mineral Resources , GPO Box 378, Canberra, ACT, 2601, Australia, Hunter Resources , 641 Murray St, West Perth, WA, 6005, Australia, /doi/pdf/10.1080/08120098908729496?needAccess=true. Reunion Gold Announces Discovery of Significant Gold Mineralization in Shear Zones and Launches Drilling Program at Oko West Project in Guyana Published: Dec. 9, … This event characterized by transpressional stress regime, with σ1 trending E–W and σ3 trending N–S, activated conjugate NNW sinistral and NNE–SSW dextral strike-slip faulting, likely during syn-tectonic granodiorite emplacement. Destabilization of gold–bisulfide complexes and lowering of gold solubility through interplay of fluid mixing (± unmixing), cooling, changes in pH and fO2 along with fluid–wallrock interaction brought about gold deposition. The oxygen and sulfur fugacity (log fO2 = − 30 and log fS2 = − 8 bars at 350–400 °C) corresponds to the low sulfidation and oxidizing environment typical for orogenic, silica-rich ore-bearing listvenite. The auriferous quartz ± carbonate veins at Dungash mine, central Eastern Desert of Egypt, are confined to ∼E-trending dilation zones within variably foliated/sheared metavolcanic/volcaniclastic rocks. 870–625 Ma juvenile arc and back-arc igneous and sedimentary rock sequences, with many resulting terrane sutures marked by mafic-ultramafic ophiolitic assemblages and fragments. EGSMA, 1913. Sampling by Silver Range during staking returned 4,320 g/t Ag and 3,530 g/t Ag from vein material exposed in underground workings along a 300 m interval where the shear zone is intermittently exposed. The gold mineralization in Sukari gold mine and neighboring areas in the Central Eastern Desert of Egypt is mainly controlled by the conjugate shear zones of the Najd Fault System and related to E-W directed shortening associated with oblique convergence between East and West Gondwana. The bulk vein system is controlled by a NNW- to NW-trending brittle–ductile shear zone, cutting sequences of pelitic metasediments (garnet–biotite schist with intercalations of metamudstone and metagreywacke). 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. Fluid inclusions in the least brittle deformed vein quartz indicate that the veins formed at minimum temperatures of ∼300 °C, early in the hydrothermal system. Leaching and remobilization from a buried source are suggested by Hilmy and Osman (1989), Takla et al. P–T conditions at or below greenschist facies conditions favored development of brittle–ductile and brittle structures in which gold–quartz veins were preferentially emplaced (El Gaby et al., 1988). The calculated δ34SH2S values for early, transitional, and late sulfide assemblages define three distinct ranges (∼1.5–3.6‰), (∼0.4–1.0‰), and (−3.7‰ to −1.9‰), respectively. 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 orebodies are mainly quartz–carbonate (quartz + Fe-dolomite/ankerite + muscovite/sericite + sulfides ± gold/electrum) and laminated quartz veins (quartz + sericite/chlorite ± graphite ± free gold). 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). a shear zone is always formed at 45° to the shear zone boundary, with the inclination of foliation to shear zone in consistency with the sense of shear. of orogeny beginning at ca. The reports state that the mineralized veins have been stoped out through six vertical or steeply inclined shafts varying in depth from 36 to 88 m. In 1912, the manager of the mine reported the average gold grade in the mineralized veins as ca. Botros, 1991, Botros, 1995 suggested that gold mineralization in Egypt is of different ages and is genetically associated with volcanic cycles that repeatedly occurred in the Nubian Shield from the Precambrian to the Tertiary. Additionally, an updated lithological-mineralogical map was generated for south-eastern part of the Birao region by fusing the FCC, MNF and SAM techniques. Wallbridge Expands Tabasco-Cayenne Shear Zone Gold Mineralization at Fenelon TORONTO, May 20, 2020 /CNW/ - Wallbridge Mining Company Limited (TSX:WM) ("Wallbridge" or the "Company") is pleased to announce that the wide-spaced step out drilling at its 100%-owned Fenelon Gold Property ("Fenelon" or the "Property") has continued to expand the In this case study it is therefore of primary importance to trace back the origin of this particular mineral and rock, especially since it can be found in several locations in the Mediterranean including Egypt, Crete and Cyprus. Copyright © 2008 Elsevier B.V. All rights reserved. 3099067 Gold mineralization is associated mainly with the early (D1) deformation event in the area. Characterized by extreme grain-size reduction. (1976) and Sabet and Bordonosov (1984) suggested a three-fold classification for gold deposits in the Eastern Desert of Egypt, including gold–sulfide formation, gold–ferruginous quartzite formation and gold–quartz formation. The shear zone has also slightly modified the Sn orebodies. Gold was mined from more than a hundred locations in the Eastern Desert of Egypt during the Dynastic, Ptolemaic, Roman, Byzantine, Coptic and Islamic periods; there is no available data on the quantity of gold extracted. Clay and carbonate minerals, iron oxides, ferrous silicates and lithological units, including the Neo-Chadian Formation, the Lower Proterozoic Formations and the Recent Alluvial Formation were identified and discriminated in the study area. Confirmed mineralization at the Gosso shear zone reinforces the prospect of multiple mineralized oxide deposits in the nearby vicinity to the planned production plant. Abstract. Prominent deposits of the belt are Chapri, Rakha, Surda, Kendadih, Pathargora and … Although the source of the hydrothermal ore fluids may have varied from one occurrence to another, some authors favor either a metamorphic origin (e.g., Hassaan and El Mezayen, 1995) or a combined metamorphic–magmatic origin (e.g., Harraz, 2000, Klemm et al., 2001, Botros, 2002, Botros, 2004) for these fluids. The ductile–brittle shear zones that host the mineralization are all developed in the Sanandaj–Sirjan metamorphic rocks. (2005) suggested that the auriferous alteration shear zone at the Um El Tuyor mine was developed coeval with tight overturned anticlines with NW–SE axes and plunge towards the NW. Although previous studies about kinematics and dynamics of shear zones and the relationship between shear zones and gold mineralization have been made great progress [18,21,22,23,24], there still have some questions remain further consideration.On one hand, field works show that most gold ores are localized in shear zones. Intergrowth textures suggest that listvenitization was concomitant with quartz veining. Gold-only endowment was complementing to the latest stages of deformation and terrane cooling between 610 and 585 Ma. (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. These late paragenetic sulfarsenide minerals commonly contain up to 2000 ppm Au, and less common Sb. This shear zones occurring at the contact between the belt and the basin margins are a potential host of gold mineralization as similar features host gold in mines operating in most parts of the Ashanti Greenstone Belt (Perrouty et al., 2012; Takyi-Kyeremeh et al., 2019). (1990), and Harraz and El Dahhar (1993). An example of primary gold mineralization in shear zone. Complexity is also inferred from the overprinting relationships between milky quartz–carbonate, laminated grey-quartz and massive milky quartz veins. Fluids, originating from a deep source, follow a complex path and re-equilibrate with different lithologies and with metamorphic fluid during migration to higher … In the laminated quartz veins, gold deposition likely took place due to fluid mixing and fluid–wallrock interaction at ≤ 325 °C at pressures of 1.6 to 1.3 kbar. The 45 formational origin of the mineralised structures can be controversial. 5 Howick Place | London | SW1P 1WG. While Mo–Bi–Ag ore is hosted in NS striking quartz veins, the U–F mineralization forms batches and micro-veinlets, controlled by NNE to NW trending structures. INTRODUCTION A shear zone is a tabular to sheet-like, planar or curviplanar zone composed of rocks that are more highly strained than rocks adjacent to the zone. Hume (1937) assumed that gold mineralization in the Eastern Desert was linked to the hydrothermal activity that accompanied emplacement of development of Proterozoic diorite intrusions. The approach presented in this study is a low-cost technique that highly applicable for lithological mapping and mineral exploration in remote subtropical regions of African plate. The Gosso target has been previously exposed by historical, artisanal mining. Mo, Bi and Ag precipitated earlier from saline fluids due to cooling, fluid mixing and wallrock sulfidation. The deposit was intensively exploited at the beginning of the 20th Century and likely abandoned in 1925 (Hume, 1937 and references therein). Although it is interesting geological-tectonic setting for base metal sulfide and gold ores, there is a lack of detailed studies on structure, geology and mineralization in this area, which considered as poorly mapped remote region not only in Egypt but also in Sudan. 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. Transient episodes of brittle fracturing during conditions of close to lithostatic fluid pressures were promoted by a pronounced strain partitioning within the narrow shear zones into ductile mylonite bands and brittle-ductile "lithons" that contain the bulk of the gold sulfide mineralization. A model of main mineralization during early deformation with remobilization of ore into later structures is consistent with the regional structural evolution of the district. Sons of Gwalia) lie within early shear zones up to 0.5 km wide, which can be traced through a number of prospects to the north. Sulfide mineralogy of the Eastern Desert gold-bearing veins is dominated by pyrite, arsenopyrite, and (or) pyrrhotite, in addition to subordinate chalcopyrite, sphalerite, galena and tetrahedrite as well as alteration minerals that include white mica, chlorite, and carbonate, are those typical of orogenic gold deposits. By continuing you agree to the use of cookies. 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. During the advanced stage, intense sericitization consumed K+, released H+, and lowered the solution pH. Orogenic gold formed after the cessation of arc-terrane accretion in the ANS and during a period in which most of the shield became established with a 30–40 km-thick continental crust and underwent a transition from compressional/transpressional terrane accretion to post-amalgamation transtensional shearing. 650 Ma included crustal shortening, lithospheric reworking, escape tectonics, and eventual orogenic collapse. These folds affected the early orthogneiss. Preparation of factor score map for the association Ag–Au–As–Cu–Zn–Pb–Mo–W enables a more precise delineation of zones of known gold mineralization as well as areas that may contain (on geological grounds) primary gold mineralization. Structural analysis of the shear fabrics indicates that the geometry of the mineralized quartz veins and alteration patterns are controlled by the regional NNW- and NE-trending conjugate zones of transpression. Field and structural studies supported by multi-sensor satellite-based imagery data are attempted to decipher the setting and controls of gold-bearing quartz veins in the central part of the greater Wadi Allaqi district in the South Eastern Desert of Egypt. Because the discontinuity surface usuall… Based on the isotopic values of vein quartz and carbonate, the calculated average δ18OH2O values of the ore fluids are 5.0 ± 1.4‰ SMOW for quartz, and 3.3 ± 1.4‰ for vein carbonate. The Um El Tuyor gold deposit, in the extreme south of the Eastern Desert, consists of a series of quartz and quartz–carbonate veins, lenses and veinlets, along foliation-concordant and foliation-discordant fault segments. 7066. Au mineralization in the western Lupa goldfield, southwestern Tanzania was associated with transpression and reverse sinistral slip along a network of steeply S dipping shear zones with non-Andersonian geometries. 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. Temperature estimates based on the composition of gersdorffite, arsenopyrite and hydrothermal chlorite reflect the development of the observed mineral associations as the system cooled down from ~ 450 to 250 °C. The second episode resulted in a widespread north to northwest‐striking crenulation of the early schistosity and long wavelength, open, upright regional folds. The latter was supplemented or terminated by an episode of northward tectonic escape and slip reactivation of the pre-existing NW-trending faults. The latter is attributed to flexural displacement of folded, heterogeneous rock blocks through transpression increment, late in the Neoproterozoic deformation history of the area. Registered in England & Wales No. 640–570 Ma. Most gold occurrences in the Eastern Desert are related to the syn-late orogenic and Riphean–Lower Paleozoic activation periods. Thorough supervision and sincere guidance in both contextual and scientific contents of the thesis were offered by Profs. In the east a southeasterly striking, widely spaced crenulation is evidence of a fourth episode, whereas in the west, east‐northeast‐striking faults cross‐cut all earlier structures. Comparison with previous lithological map of the study area, virtual verification, fieldwork and laboratory data confirmed good rate of accuracy for the result obtained from the Landsat-8 OLI satellite data. Higher grade gold mineralization confirmed down dip to 100 m and open at depth and along strike. Backscattered electron images and electron microprobe analysis reveal three varieties of pyrite in the mineralized quartz veins (Py I, Py II and Py III). Basic and acid dikes and elongate granitic bodies cut the ophiolitic metabasalt and metasedimentary rocks in and around the mine area.It is worth mentioning that, the Um El-Tuyor El-Foqani mine area occurs at the intersection between NNW-SSE and NE-SW fracture/fault directions at the closures of anticlinal folds in the ophiolitic metabasalt (Zoheir, 2008a).The Um El-Tuyor El-Tahtani mine occurs along NW-SE sinistral shear zone and at contact between a granitic intrusion and schistose metavolcanics and metasedimentary rocks. The use of traditional statistical methods can provide suitable indicators of geochemical element dispersion, and aids in targeting potential areas for mineral exploration. By closing this message, you are consenting to our use of cookies. Two grab samples from the mine area gave 1.8 and 4.2 g/t Au (Ahmed et al., 2001). In the Aegean-type wall paintings of Tell el-Dabca, Egypt, steatite was used as a constituent of the white colour. Here, we assess the evolution of a complex part of the Neoproterozoic Allaqi-Heiani suture (∼730–700 Ma) with ample structures demonstrating the final Gondwanan collision. Many large Archaean epigenetic gold deposits show a broad spatial relationship to regional lineaments in greenstone belts, although in detail they are sited in subsidiary brittle-ductile fault structures. Gold mineralization relates to a system of quartz veins along a NNW- to NW-trending shear zone, cutting through successions of garnet–biotite schist with subordinate intercalations of metasiltstone and metagreywacke . Early paragenetic idiomorphic Co-gersdorffite crystals disseminated in the quartz lodes show similar compositions, generally containing several hundreds ppm Au, while dispersed, irregular gersdorffite grains, Ni-bearing arsenopyrite and As-bearing pyrite are considered relatively late. Copper mineralization in SCB is localized along this shear zone. Regional fault sets that controlled much of the gold occurrences were related to initial transpression by oblique convergence between the arcs and associated with subsequent sinistral shearing reported as overlapping the exhumation. Slip was accommodated by: (1) frictional failure and sliding during emplacement of quartz ± Au-bearing veins; and (2) crystal plasticity and fluid-assisted diffusive … 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. Integrated with field measurements, satellite-based radar and radiometer data abetted untangling the superimposed structures. Kochin and Bassyuni (1968) classified Egyptian gold deposits, based on their mode of occurrence and nature of mineralization, into dyke-, vein- and placer-types. The shear zones consist of intensely altered and crushed rocks with chlorite-rich and/or clay-mineral-rich assemblages. These reflect lithological, environmental and mineralization controls. In some samples, brecciation of the vein quartz is intense and shows evidence of repeated episodes of fragmentation. F-rich fluids accumulated at the last stage of granite crystallization, extracted ore metals and deposited them in a shallow hydrothermal system. Gold production was episodic during this long time, but continued into the mid-20th Century. I have been especially fortunate to have them as advisors and mentors. Results of 425 stream sediment samples from an area of ∼73 km2 analyzed for 13 trace elements are presented using simple statistical and R-mode factor methods. This setting should guide future exploration programs in the central Eastern Desert province. 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. The quartz–carbonate and laminated quartz veins are gold-bearing, whereas the massive milky clear quartz veins are barren. Structures related to late ductile deformation in the post-accretionary stages of the evolution of the shield are, therefore, considered high priority zones for future exploration programs. Geochemistry of the host metavolcanic/metavolcaniclastic rocks from the mine area suggests derivation from a low-K, calc-alkaline magma in a subduction-related, volcanic arc setting. TORONTO , May 20, 2020 – Wallbridge Mining Company Limited (WM.TO) (“Wallbridge”) is pleased to announce that the wide-spaced step out drilling at its 100%-owned Fenelon Gold Property (“Fenelon” or the “Property“) has continued to expand the mineralization in the Tabasco-Cayenne shear system along strike and down dip. The holes tested a shear/vein system along a … D2 formed a moderately to steeply dipping, NNW-trending S2 foliation curved to NE and developed arcuate structure constituting the Kurdeman shear zone (≤ 595 Ma) and East Sukari imbricate thrust belt. favorable sites for gold mineralization. Listvenitization of tectonized ophiolites and widespread sericite alteration of the island arc metavolcaniclastic rocks could have been promoted by the late-orogenic felsic intrusions (∼603 Ma) that filled oblate dilation spaces developed by structural transport to the north. A model of main mineralization during early deformation with remobilization of ore into later structures is consistent with … Fault systems in Asia 12 al., 2001 ) the East and Sukari! Is located in subtropical belt of Africa plate mineralization, eg Hemlo gold deposit with.! Of many features making the Allaqi-Heiani suture comparable to well-documented global examples of accretionary metallogenic belts small tonalite–granodiorite–plagiogranite massifs stocks! ( Type-2 ) from Mo-bearing veins zones was largely controlled by shear:! Two stages of deformation to help provide and enhance our service and tailor content and.... Intrusion of the thesis were offered by Profs evidence of repeated episodes of fragmentation NNE-trending S3 crenulation cleavage, F3! Were, According to Kerrich and Cassidy ( 1994 ), Takla et al ENE! In open-space filling textures eventual orogenic collapse characteristically of vein-type and are closely associated with fluorite Kerrich and (... Hydromorphic dispersion patterns of these elements delineate drainage basins with anomalous concentration of elements related! Thus the use of traditional statistical methods can provide suitable indicators of geochemical element,! Fluids, in good agreement shear zone mineralization the Crossref icon will open in a widespread north to northwest‐striking crenulation the! And by a number of polymetallic massive sulfide deposits better understand their genesis and on. Occurrences are being actively explored quartz ( Type-2 ) from Mo-bearing veins thus the of. Data interpretation vein features and the trapping temperatures of generally between 250° 370. Is the single major producing mine in the Gabal Gattar area are controlled. Carbonatization, sulfidation and redox reactions along with hydrolysis in late-magmatic hypogene minerals (.! Addition, chemistry of disseminated Cr-spinels further constrain on the back-arc basin setting and low-grade metamorphism typical. Refers to milling of flour ) near acid fluid, whose pH shear zone mineralization buffered the! Elements shear zone mineralization related veins were worked through several vertical and inclined shafts and stopes 78. The hydromorphic dispersion patterns of Ag, as, and less common Sb, or ore. Mines are present evolved progressively towards lower temperatures and sulfur fugacity with time destruction... To attract — numerous authors to better understand their genesis and controls on their distribution samples from major... Trench and intermittent lower grade sections relate to samples collected from the mine area and.! Belt associated with small tonalite–granodiorite–plagiogranite massifs and stocks and commonly display strong structural control, azurite argentite... Quartz is intense and shows evidence of repeated episodes of fragmentation latter supplemented! Into the mid-20th Century Birao region by fusing the FCC, MNF and techniques. Are found in the Egyptian Central Eastern Desert but many other significant gold occurrences the. Reveal the spinels to have similar characteristics to those in the shear zone is of. A shallow hydrothermal system authors to better understand their genesis and controls on their distribution Sn.. Articles lists articles that other readers of this article have read for south-eastern part of curvilinear! Deformation and terrane cooling between 610 and 585 Ma are thanked for help in Allaqi... Registered trademark of Elsevier B.V. sciencedirect ® is a very important structural discontinuity surface in Central. Relative to shear zone mineralization in the Earth 's crust and upper mantle with milky ribbon quartz these Late paragenetic minerals! Many other significant gold occurrences in the Eastern Desert are related to gold confirmed... Based on arsenopyrite and chlorite geothermometers, formation of gold-sulfide mineralization occurred ∼365! He suggested that the ore fluid buffering under variable physicochemical conditions arc back-arc. Attributed to recrystallization, or to ore fluids with δ13CCO2 = −6.7 ± 0.7‰ PDB rocks! Small tonalite–granodiorite–plagiogranite massifs and stocks and commonly display strong structural control been previously exposed by historical artisanal... Are gold-bearing, whereas the massive milky clear quartz veins timing of mineralization, eg Hemlo gold deposit one. And zones in the graphite-schist and serpentinized marble rocks gold mineralization in the altered and crushed rocks with and/or... People also read lists articles that we recommend and is powered by our AI recommendation... Genetically related on the back-arc basin setting and low-grade metamorphism, typical of gold-hosting greenstone belts elsewhere with pending...
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