Characteristic of gold mineralization associated with granites at Hamash old gold mine, South Eastern Desert, Egypt

被引：4
作者：
El-Desoky H.M. [1 ]
Shahin T.M. [1 ]
Amer Y.Z. [2 ]
机构：
[1] Geology Department, Faculty of Science, Al-Azhar University, PO Box 11884, Nasr City, Cairo
[2] Hamash Misr for Gold Mines Company, Cairo
来源：
Arabian Journal of Geosciences | 2021年 / 14卷 / 7期
关键词：
Egypt; Geochemistry; Gold mineralization; Hamash gold mine; Hydrothermal alteration; Quartz veins;
D O I：
10.1007/s12517-021-06923-9
中图分类号：
学科分类号：
摘要：
Well-known controversy over the genesis of orogenic gold mineralization in granites has been a subject of research worldwide. Hamash gold mine is considered one of the pharaohs mines in the South Eastern Desert of Egypt, where gold mineralization is hosted by granites. In this study, we utilized field, ore microscopy, and geochemical data to determine the genesis of granites and the associated gold deposits. We found that the granites, intruded into island-arc metavolcanics and metavolcanoclastic assemblages, are characterized by variable major and trace elements, calc-alkaline, and I-type granitoids that reflect a fractional crystallization. Their trace and rare earth elements reflect magma that is related to subduction tectonic setting. The gold mineralization is confined to quartz veins that cut through granitic rocks, extend in NW-SE and N-S directions, and are formed during shear-extensional tectonics. The gold is found with sulfides in quartz veins and wallrock alteration. Silicification and sericitization are the most hydrothermal alteration zones associated the ore formation, comprise an inner quartz-sericite-carbonate-chlorite-sulfide assemblage. The results of chemical analysis reveal an increase of SiO2, Fe2O3, S, and L.O.I. concentrations and moderate depletion in K2O, Na2O, and LILE suggesting that they were affected by mineral replacement reactions and sulfidation in the altered wallrocks close to Au-quartz veins. The gold is represented by tiny inclusions, with minor chalcopyrite, galena, and arsenopyrite that mainly fill the microfracture in quartz and pyrite grains. Furthermore, a general model of gold mineralization suggests that the gold was contemporaneously formed during syn-orogenic stage, transpressional deformation assigned to D2 deformation, and subduction-related thermal processes followed by gold-bearing fluids that fill the fractures, forming veins. © 2021, Saudi Society for Geosciences.
引用
收藏
相关论文
共 47 条
  • [1] Abd El-Wahed M.A., The role of the Najd Fault System in the tectonic evolution of the Hammamat molasse sediments, Eastern Desert, Egypt Arab J Geosci, 3, 1, pp. 1-26, (2010)
  • [2] Abd El-Wahed M.A., Harraz H., El-Behairy M.H., Transpressional imbricate thrust zones controlling gold mineralization in the Central Eastern Desert of Egypt, Ore Geol Rev, 78, pp. 424-446, (2016)
  • [3] Abdeen M.M., Sadek M.F., Greiling R.O., Thrusting and multiple folding in the Neoproterozoic Pan-African basement of Wadi Hodein area, south Eastern Desert, Egypt, J Afr Earth Sci, 52, 1-2, pp. 21-29, (2008)
  • [4] Abdel-Karim A.M., Et al., Neoproterozoic ophiolitic and arc metavolcanics of Egyptian Nubian Shield, The geology of the Egyptian-Nubian Shield”. Book series: “Regional Geology Reviews”, Chapter no. 8, pp. 1-31, (2020)
  • [5] Abdel-Karim A.M., Ahmed Z., Possible origin of the ophiolites of Eastern Desert of Egypt, from geochemical prospectives, Arab J Sci Eng, 34, 1C, pp. 1-27, (2010)
  • [6] Abdelsalam M.G., Stern R.J., Sutures and shear zones in the Arabian Nubian shield, J Afr Earth Sci, 23, pp. 289-310, (1996)
  • [7] Ali B.H., Wilde S.A., Gabr M.M.A., Granitoid evolution in Sinai, Egypt, based on precise SHRIMP U–Pb zircon geochronology, Gondwana Res, 15, 1, pp. 38-48, (2009)
  • [8] Avigad D., Gvirtzman Z., Late Neoproterozoic rise and fall of the northern Arabian–Nubian shield: the role of lithospheric mantle delamination and subsequent thermal subsidence, Tectonophysics, 477, pp. 217-228, (2009)
  • [9] Bierlein F.P., Groves D.I., Cawood P.A., Metallogeny of accretionary orogens — the connection between lithospheric processes and metal endowment, Ore Geol Rev, 36, 4, pp. 282-292, (2009)
  • [10] Botros N.S., A new classification of the gold deposits of Egypt, Ore Geol Rev, 25, 1-2, pp. 1-37, (2004)
12345