Related Papers
Mineralogy and Petrology
Mineralogy and Fluid inclusion studies of the Au-Cu quartz veins in the Hamash area, South-Eastern Desert, Egypt
1999 •
Reinhard Kaindl
Field relations, petrographic observations and fluid inclusion data are used to characterize the mineralizing fluids of gold-copper bearing quartz veins, which are spatially associated with a granite-porphyry, metavolcanics and metagabbro in the Hamash area, South Eastern Desert of Egypt. Four generations of genetically related quartz veins occur in the Hamash mine area. Two types of alteration are developed in vicinity of quartz veins; i.e., sericite-quartz-pyrite and chlorite-epidote-pyrite-sericite alteration. Fe-Cu sulfides in the veins were precipitated in two stages, early pyrite (PI) and chalcopyrite were altered to secondary chalcocite, bornite and digenite and a second generation of pyrite (PII and PIII). PI pyrite and quartz contain inclusions of gold as well as remobilized gold along cracks and microfractures. Two types of fluid inclusions are distinguished: 1) primary H2O-CO2-CH4-NaCl inclusions (type I) and 2) primary and secondary aqueous inclusions (type II). Type II is further subdivided by the inclusions occurrence within different vein types. Type I inclusions entrapped the endmembers of an unmixed fluid which consists of an aqueous phase and a CO2-rich gas phase, respectively. The entrapment conditions of approximately 250°C and 200 bars were estimated by intersecting the isochores of the two coexisting aqueous and CO2-rich fluids and indicate a shallow crustal level. The salinity of type IIa inclusions is generally low (< 9 wt.% NaCleq), they hom*ogenize above 234°C and included heterogeneous and hom*ogeneous fluids over a wide pressure range. hom*ogenization temperatures of type IIb inclusions vary between 102° and 284 °C, their assumed entrapping temperatures are 200°C and 110°C, respectively. The four generations of quartz veins are related with different inclusion types. The metals including primary gold were probably transported as bisulfide complexes and precipitated due to wallrock sulfidation, fluid mixing and phase separation. The Hamash Au-Cu mineralization shows a combination of porphyry- and epithermal-deposits characteristics. Geländebeziehungen, petrographische Beobachtungen und Untersuchungen an Flüussigkeitseinschlüssen erlauben die Charakterisierung der mineralisierenden Fluide in Gold-Kupfer-führenden Quarzgängen, die mit einem Porphyr-Granit und einem Gabbro im Hamash Gebiet der südöstlichen Wüste von Ägypten assozüert sind. Vier Generationen von Quarzgängen kommen im Gebiet der Hamash Mine vor. Zwei Alterationstypen sind in der Nähe der Quarzgänge ausgebildet: Serizit-Quarz-Pyrit und Chlorit-Epidot-Pyrit-Serizit Alteration. Die Fe-Cu-Sulfide in den Gängen wurden in zwei Etappen ausgefällt, früh kristallisierter Pyrit (PI) und Kupferkies wurden zu sekundärem Chalkosin, Bornit und Digenit sowie einer zweiten Generation von Pyrit (PII und PII) umgewandelt. PI Pyrit und Quarz enthalten sowohl Gold-Einschlüsse als auch remobilisiertes Gold entlang von Spalten und Mikrobrüchen. Zwei Typen von Flüssigkeitseinschlussen wurden unterschieden: 1) primäre H2O-CO2-CH4-NaCl Einschlusse (Typ 1), 2) primäre und selcundäre wäßrige Einschlusse (Typ II). Typ I Einschlusse schlossen die Endglieder eines entmischten Fluides ein, das aus einer wässrigen bzw. einer CO2-reichen Gasphase bestand. Die Einschlußedingungen von ungefähr 250°C und 200 bar wurden durch den Schnittpunkt der Isochoren der beiden koexistierenden Fluide bestimmt und zeigen einen seichten Krustenbereich an. Die Salinität von Typ Ila Einschlussen ist generell niedrig (<9 Gew.% NaCleq), sie hom*ogenisieren uber 234 °C und schlossen heterogene und hom*ogene Fluide über einen großen Druckbereich ein. Die hom*ogenisationstemperaturen von Typ IIb Einschlussen variieren zwischen 102° und 284°C, ihre angenommenen Einfangtemperaturen liegen bei 200 °C bzw 110 °C. Die vier Generationen von Quarzgängen stehen in Zusammenhang mit den verschiedenen Typen von Flussigkeitseinschlussen. Die Metalle, einschließlich des primaären Goldes, wurden wahrscheinlich als BisulphidKomplexe transportiert und auf Grund von Sulfidisierung der Nebengesteine, Fluidmischung und Phasenseparation ausgefällt. Die Hamash Au-Cu Mineralisation zeigt eine Kombination von Porphyr- und Epithermal-Lagerstätten Charakteristika.
Ore Geology Reviews
Characteristics and genesis of shear zone-related gold mineralization in Egypt: A case study from the Um El Tuyor mine, south Eastern Desert
2008 •
Basem Zoheir
Geological Society, London, Special Publications
Gold mineralization in the Proterozoic Bleida ophiolite, Anti-Atlas, Morocco
2008 •
Michel Jebrak
Bi- Sulfosalt Mineral Series and Their Paragenetic Associations in Specula Rite-Rich Cu-Ag-Au Deposit, Qaleh-Zari Mine, Iran
2005 •
mohammad hassan Karimpour
Qaleh-Zari specularite-rich Cu-Ag-Au deposit is located 180 Km south of Birjand, in eastern Iran. Host rocks are mainly Tertiary calc-alkaline to K-rich calc-alkaline of 40.5±2 Ma and Jurassic sandstones and shales. Three major sub-parallel steep quartz veins are identified in different rock types, in particular andesitic rocks. The Qaleh-Zari deposit is a specularite-rich hydrothermal, Cu-Ag-Au vein type deposit. Several complex Cu-Pb-Bi and AgPb-Bi sulfosalt minerals have been identified in samples from different vein mineralization. Based on the paragenesis and fluid inclusion data temperature of hom*ogenization, four ore-forming stages are identified in the area. In the first stage, specularite, chlorite, chalcopyrite and Bi-sulfosalts, (aikinite, matildite and wittichinite) were formed. The temperature of the hom*ogenization of the fluid inclusions for the first stage ranges as 380 to 290°C. In the second stage, pyrite, chalcopyrite, chlorite, aikinite, cosalite, wittichinite and...
The Tamlalt-Menhouhou Polyphase Gold Deposit (High-Atlas, Morocco): IOCG-type Mineralisation Overprinted by Shear-Zone Related Gold
Dominique Gasquet
Economic Geology
Mineralogy and Paragenesis of the CoNi Arsenide Ores of Bou Azzer, Anti-Atlas, Morocco
2009 •
Moha Bou
Gold and Antimony Mineralizations of Jbel Haouanite (High Atlas, Morocco) in Their Geodynamic Context
European Scientific Journal ESJ, Boushaba Abdellah
The gold and antimony mineralizations of Jbel Haouanite (Eastern High Atlas, Morocco) are hosted by quartz veins in tectonic structures carried by Ordovico-Silurian Paleozoic formations. At least three phases of folding tectonics affected the area, inducing three generations of folds accompanied by two flow schistosities and a fracture one. Magmatic intrusions of a rhyodacitic nature are post-Silurian and prior to mineralization. From a mineralogical point of view, paragenesis includes native gold, stibnite, valentinite, stibiconite, as well as antimony and lead sulfosalts. Petrographic studies and chemical analyzes show the lack of correlation between gold and the different elements. Thus, the gold would have deposited later to antimony and is associated with oxidation minerals, especially valentinite. The results of the analyzes on different diagrams makes it possible to conclude that the gold mineralizations are of the mesozonal to epizonal orogenic type and they would be late-Hercynian.
Geochemistry
Iron oxide copper-gold (IOCG) mineralization at the Imiter inlier, Eastern Anti-Atlas, Morocco
2018 •
Said Ilmen
Minerals
The Shah-Ali-Beiglou Zn-Pb-Cu (-Ag) Deposit, Iran: An Example of Intermediate Sulfidation Epithermal Type Mineralization
mohsen moayyed
The Cu-Mo±Au Mineralizations Associated to the High-K Calc- Alkaline Granitoids from Tifnoute Valley (Siroua massif, Anti- Atlas, Morocco): an Arc-Type Porphyry in the Late Neoproterozoic Series
Mustapha Souhassou, Saïd Belkacim
Abstract The Tifnoute valley Cu-Mo±Au mineral occurrences are located NW of Siroua massif in the central Moroccan Anti-Atlas. This mineralization appears to be associated to the Imourkhssan granite and the Asskaoun granodiorite dated respectively 561 ± 3 and 558 ± 2 Ma. These highly potassic granitoids show an arc signature and are in-placed in an extensional tectonic setting typical of the post-collision Late Pan-African period. In places, these rocks are strongly to slightly affected by hydrothermal alterations of phyllic, propylitic and argillic types with development of a pyritic facies around the Imourkhssan granite. The mineralization can be divided into two types: A molybdenite mineralization and some sulphides spatially linked to the Imourkhssan granite. It is disseminated in the granite or appears in lamellar or pluri-millimetric fragments. It also occurs as spots and nets along chloritized fractures planes oriented NNE-SSW and dipping 40 to 60 SE. The paragenesis consists of molybdenite, pyrite, chalcopyrite and sphalerite. Talat N’Lbnour Cu-Au mineralization linked to NS fractures affecting Askaoun granodiorite. The vein is about 0.5 to 2 m thick that extends about 400 m. The mineralized fractures are filled essentially with quartz, siderite and chlorite. Metallographic study reveals a diverse paragenesis that consists of pyrite, chalcopyrite, gold, bornite and chalcocite. The secondary paragenesis consists of chalcopyrite, covellite, bornite, malachite, azurite and hematite. These features of these mineralizations are discussed in the context of an arc-type Cu-Mo±Au porphyry mineralization.
