INTERPLY OF PLUTONISM FAULTING AND MINERALIZATION, NORTHEN GABAl QATTAR PERIPHERAL ZONE, NORTH EASTERN DESERT, EGYPT.

Abstract

The area of study lies at the northern Gabal Qattar peripheral zone in the Northern Eastern Desert of Egypt, bounded by latitudes 27° 02' and 27° 08' N, and longitudes 33° 14' and 33° 20' E. It is covered by the following rock units, arranged. in a chronological order starting with the oldest: Hammamat sedimentary rocks, acidic and intermediate dykes, younger granites (Qattar granites) and basic dykes. The present thesis highlighted the relation between the plutonism, faulting and uranium mineralization in this particular area.

Field relations and observations revealed that the emplacement of the Qattar granitic pluton has led to the formation of weak zones, fractures and faults around the peripheral parts of the pluton. These fractures and faults play a signifcant role. in ascending the post-emplacement hydrothermal solutions that carrying uranium mineralization.

Structural fabric elements in the area of study are represented by primary and secondary structural features. Structural field works were carried out including measuring of the attitudes of joints, fractures and faults in the different rock types in the area, besides bedding, cleavages, and folds in the Hammamat sedimentary rocks. These structural elements were statistically treated to delineate the predominant trends affected the investigated area.

The deformational history of the study area involves two phases of ductile deformations. The first phase is developed pre-dating the intrusion of the Qattar granites, while the second phase is related to, and formed due to the effect of, the emplacement of the Qattar pluton itself Folds and other structural features referred to the second phase of ductile deformation are restricted tothe exposures of the Hammamat sedimentary rocks encountered close to the contact with granites.

. The. gamma activity measurements of the area of study led to the discovery of four important uranium occurrences, namely: GI, GII, GV and GVI. These occurrences are located nearby and along the contact zone between the huge mass of Qattar granite and Hammamat sedimentary rocks.