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埃及东部沙漠地区由多种晚元古代岩石组成。它们以蛇绿岩、变辉长岩、变枕状玄武岩、岛弧变沉积岩与变火山岩组合体以及同构造期花岗岩等形式产出。蛇绿岩呈小规模、沿碳酸盐化剪切带逆冲于变火山岩之上的北北西向拉伸岩片。逆冲的岩石以发育滑石—碳酸盐、菱镁矿囊状体和石英—碳酸盐细脉为特征。埃尔贝达地区被另一条穿过变枕状玄武岩和变火山岩滑动的北西向逆冲断层所切割。石英脉与深成蚀变作用 (即硅化和绿泥石化 )广泛发育于逆冲构造面 ,构成了一条多样化的剪切带。埃尔贝克金矿位于限定在蛇绿岩和变枕状玄武岩中的两条剪切带内 (北西—南东向 )。金矿化主要与该区早期变形事件 (D1 )相伴。在晚元古代岩石板块消减期间 ,两期热液流体的注入影响着剪切带。在矿物方面 ,剪切带含有绿泥石、磁铁矿、赤铁矿、钛铁矿、黄铁矿、黄铜矿、针铁矿、褐铁矿、铜兰、斑铜矿和金。产于逆冲区蛇绿岩内的碳酸盐化剪切带 (SiO2 <50 % ) ,金含量很低 ( 0 2 4～ 0 4 5ppm) ,而变枕状玄武岩中的硅化剪切带富含SiO2 ( >80 % )且含金达 4 5ppm。观察到金以与石英连生的细颗粒金 (约 0 3mm)、微细粒包裹体金 ( 2 0～ 0 5μm) ,或以与赤铁矿和孔雀石共生的细小不规则状斑点的形式产出。也发现从蚀变赤铁矿中活化形成?
The eastern Egyptian desert consists of a variety of Late Proterozoic rocks. They are produced in the form of ophiolite, gabbro, quasi-pillow basalt, island arc metamorphic sedimentary rocks and volcanic rocks, and granitoids of the same tectonic stage. The ophiolite is a small-scale, north-west-trending extensional rock that has been thrust into volcanic rocks along carbonate-bound shear zones. The thrusting rocks are characterized by the development of talc-carbonate, magnesite blasts and quartz-carbonate veins. The area of Elbeida is cut by another northwesterly thrust that slides through variable pillow basalt and volcanic rocks. Quartz veins and deep alteration (silicification and chloritization) are widely developed in the thrust structure, forming a diversified shear zone. The Erbek gold deposit is located in two shear zones (north west-south east) confined to ophiolites and variable pillow basalt. Gold mineralization is mainly associated with early deformation events (D1) in the area. During the depletion of the Late Proterozoic rock plates, the injection of two hydrothermal fluids affected the shear band. In terms of minerals, the shear zone contains chlorite, magnetite, hematite, ilmenite, pyrite, chalcopyrite, goethite, limonite, bronze, bornite, and gold. Carbonate shear zones (SiO2 <50%) produced in the thrust zone ophiolite have low gold content (024 ~ 045ppm), while the silicified shear zones in the variable pillow basalt are rich SiO2 (> 80%) and gold up to 45ppm. Gold was observed in the form of fine-grained gold (about 0 3 mm) associated with quartz, fine-grained gold inclusions (20 to 0 μm), or fine irregular-shaped spots coexisting with hematite and malachite Out Also found from alteration hematite activation formation?