Thrust system, flower structures and transpressive duplexes in Zeidun-Kareim Belt, Central Tectonic Province, Egyptian Nubian Shield (East African Orogen)

Abstract

Abstract In this study, we explore thrust system, flower structures and transpressive duplexes in the Zeidun-Kareim belt (ZKB) in the Egyptian Nubian Shield (ENS; northwestern ANS). Filed observations and the measured stretched lineations along thrust planes reveal two main thrusting directions; ESE- (to NE- and NNE-)- and NW- (to WNW-)-directions belonging to two main phases of contraction. The timing of both phases is indirectly constrained. The older ESE- (to NE- and NNE-)-vergent thrusting is attributed to the E-W Gondwana assembly. The younger NW- (to WNW-)-vergent thrusting is akin to the Najd Orogeny. The poles to the in-sequence thrusts lie close to the poles of stretching lineations. The mean orientations of thrust propagation are, respectively, 059° and 309°. Propagation of thrusting along the two main thrusting directions resulted in the formation of a complete geometry of thrust duplex system, imbricate nappe stacking, flower structures and thrust-related folding. The top-to- ESE- (to NE- and NNE-) transpression reflects dextral sense, whereas the top-to- NW- (to WNW-) transpression exhibits sinistral sense, in compatible with those recorded and argued by many authors elsewhere in the ENS and the entire ANS. Our study fully constraints the ZKB spathio-temporal tectonic evolution which involves three main stages.

Keywords

• Arabian-Nubian Shield
• East African Orogen
• Najd Orogeny
• Thrust duplexes
• Transpression