Geochemical Studies and Tectonic Control of Gold Mineralization in the Bayuda Desert, Northern Sudan with Especial Emphasis on Hagaggia Area

Abstract

The study area is located in the northem sector of the Sudan; at the western side of the River Nile. Geotraverses and laboratory examinations indicate that the area comprises different Lithological units; high-grade gneisses, Volcanosedimentary sequences intercalated with minor intrusions (quartz veins, dykes and amphibolite bands). The tectonic boundary that separates the high- grade rocks from the low-grade rocks is a thurst boundary as confirmed by petrographic descriptions of the rocks. The study area is subjected to multiphase of deformation, the evidence for this deformation, which has been seen in the area, includes folding, faulting and shearing, in addition to microscopic evidence. Low-grade rocks (sercite-mica schist, muscovite schist), and calcsilicate host the sulphides and associated gold elements, in addition to diorite and felsite dykes). The sulphides minerals and gold deposit are controlled by major deformation zone. The gold occurrences in the area seem to be situated in brittle- ductile structure that formed as the result of extensional shear deformation. The geochemical samples for gold prospecting and its associated elements include stream sediments, residual soil and rock chip samples. The soil samples were collected from the B-horizon, prepared and fmally analyzed for Au, Ag, Zn, Pb and Cu.The results obtained revealed that, the effective use of stream sediments and soil samples for detecting gold mineralization.

The discrimination diagrams indicate that, the rocks of the study area are of volcanic arc tholeiitic and calc-alkaline setting, which were probably formed at first stage of subduction and island arc.