Controls on quartzite bearing base-metal sulfide and invisible gold mineralization at Gabal Abu Houdied area, South Eastern Desert, Egypt

The Neoproterozoic basement rocks cropping out in the Gabal Abu Houdied (GAH) area comprises mainly three lithotectonic assemblages; mafic–ultramafic ophiolitic rocks, island arc-related metasediment–metavolcanic rocks and syn- and post-tectonic intrusions. The base-metal sulfide and invisible gold mineralization are restricted to quartzites, which are considered as member of island arc-related metasediment rocks. The mineralized quartzite rocks are cropped out at three localities, at Wadi El Haussioum where cover a small area (0.25 km2), at Bir Abu Houdeid, cover small area (0.5 km2), and at Bir Shani (3.5 km long with different width ranging from 4 to 75 m). Based on textural characteristics and chemical features, documented by electron probe microanalysis (EPMA) and inductively coupled plasma mass spectrometry analyses (ICP-MS), two phases of sulfide minerals assemblages in the investigated quartzites of GAH area. An early mineralization phase includes pyrite, pyrrhotite, argentite (acanthite) and invisible gold, and the late phase, dominated by pyrite, galena, sphalerite, chalcopyrite, covelite, and ± invisible gold. Analyses of the structural data collected from the quartzite rocks and surroundings indicated that the base-metal sulfide and associated gold mineralization in the GAH area are mostly controlled by D3 transperssional deformation event. This event is main Hamisana shear zone (HSZ) deformation event and characterized by transperssional stress regime, with σ1 trending E–W and σ3 trending N–S governed conjugate NNW sinistral and NNE–SSW dextral strike slip faulting.