Ediacaran (~ 600 Ma) orogenic gold in Egypt: age of the Atalla gold mineralization and its geological significance

<p>Integration of a new monazite U–Pb age for the Atalla monzogranite (615 ± 9 Ma) and a ⁴⁰Ar/³⁹Ar plateau age of hydrothermal white mica (601 ± 5.5 Ma, 2σ) disseminated in gold-bearing quartz veins at the Atalla mine indicates post-intrusion Au-mineralization, overlapping with cooling and regional exhumation ages of the Central Eastern Desert. The mica age is in agreement with published Re–Os age of gold mineralization in the Fawakhir area, ~ 20 km to the south along the Atalla shear zone. The new geochronological data demonstrate lode gold formation during the ~ 600 Ma period, controlled by wrench tectonics along Najd-related structures in the region (620–585 Ma). Fluid focusing and gold deposition during the Ediacaran were promoted by contrasting lithological and rheological properties at the granite-ophiolites contacts. This seems to be a typical setting for gold ores in this part of the Nubian Shield, and can aid exploration for undiscovered resources in the region.