The Sukari Neoproterozoic granitoids, Eastern Desert, Egypt: Petrological and structural implications

Abstract

The Sukari granitoid pluton is situated in the southern central Eastern Desert of Egypt and is considered as one of the best examples of the gold–bearing granites in the Arabian Nubian Shield (ANS). It consists of coarse– to medium–grained alkali–feldspar granite, syenogranite and monzogranite intruded the volcano–sedimentary sequences and metagabbro–diorite complex. Geochemically, these granitoids are metaluminous to peraluminous in character. They are characterized by positive Rb, K, Zr and Pb and negative Ba, Sr, P, Nb and Ti anomalies and exhibit similar trace element patterns. Moreover, they show pronounced LREE–enriched patterns and negative Eu anomalies that indicate plagioclase fractionation. The studied rocks are typical of within plate granites generated in tensional environment. They belong to ferroan/A–type granites, particularly A2–type suggesting post-collisional setting. Their high SiO2, Al2O3 and low MgO contents along with the low Ce/Pb ratios reflect derivation from melting crustal source.The major structures of the Sukari area encompass Akbar Wahid, Golden Boy, Buthinae and Kaolinitic Faults. The area is characterized by NNE-NE trending shear zone and WNW-EW stress orientation. The mineralized structures contain quartz veins trending mostly EW, NS and NNW; joints with NS, EW, NNE and NNW trends; faults with NNW, NNE, NS and EW trends; and breccia with NNW trend. The kinematic indicators are represented by mylonites, quartz fish and augen structures. Mineralization in Sukari area found as quartz veins, stockworks and brecciated veins.