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Mubarak shear belt provides an opportunity to investigate quantitative finite strain (Rs), proportions of pure shear and simple shear components, sense of shear indicators, subhorizontal to steeply plunging mineral lineations, in a dextral transpressional zone. The structural style of the Mubarak shear belt is consistent with dextral transpression within the Central Eastern Desert where dextral and reverse shear have developed simultaneously with the regional foliation. The high strain zone of the Mubarak shear belt is characterized by steeply dipping foliation with sub-horizontal stretching lineation (simple shear) surrounded by thrust imbrications with slightly plunging stretching lineations. Strain estimates from the Mubarak shear belt are used to determine how pure and simple shear components of deformation are partitioned. The axial ratios in XZ sections range from 1.16 to 2.33 with the maximum stretch, S , ranges from 1.06 to 1.48. The minimum stretch, S , ranges from 0.65 to 0.92 indicating a moderate variation in vertical shortening. Volcaniclastic metasediments and metagabbros were subjected to prograde low-grade regional metamorphism in the range of greenschist to lower amphibolite facies (450-650°C at 2-4 kbar). Medium pressure (6-8 kbar at 530°C) was estimated from the high strain zone within the dextral strike-slip shear zones. Retrograde metamorphism occurred at a temperature range of 250-280°C. There is a trend towards decreasing the ratio of 100Mg/(Mg + Fe + Mn) away from the high strain zone of the Mubarak shear belt. Integrated strain and temperature estimates indicate that the simple shear (non-coaxial) components of deformation played a significant role in formation and exhumation of the Mubarak shear belt during the accumulation of finite strain and consequently during progressive transpression and thrusting. [ABSTRACT FROM AUTHOR]

Strongly deformed volcaniclastic metasediments and ophiolitic slices hosting the Sukari gold mineralization display evidence of a complex structural evolution involving three main ductile deformational events (D 1 –D 3 ). D 1 produced ENE-trending folds associated with NNW-propagating thrust slices and intrusion of the Sukari granite (689 ± 3 Ma). D 2 formed a moderately to steeply dipping, NNW-trending S 2 foliation curved to NE and developed arcuate structure constituting the Kurdeman shear zone (≤ 595 Ma) and East Sukari imbricate thrust belt. Major NE-trending F 2 folds, NW-dipping high-angle thrusts, shallow and steeply plunging mineral lineation and shear indicators recorded both subhorizontal and subvertical transport direction during D 2 . D 3 (560–540 Ma) formed NNE-trending S 3 crenulation cleavage, tight F 3 folds, Sukari Thrust and West Sukari imbricate thrust. The system of NW-trending sinistral Kurdeman shear zone (lateral ramps and tear faults) and imbricate thrusts (frontal ramps) forming the actuate structure developed during SE-directed thrusting, whereas the prevailing pattern of NNE-trending dextral Sukari shear zone and imbricate thrusts forming Sukari thrust duplex developed during NE-directed tectonic shearing. Sukari granite intruded in different pluses between 689 and 540 Ma and associated with at least four phases of quartz veins with different geometry and orientation. Structural analysis of the shear fabrics indicates that the geometry of the mineralized quartz veins and alteration patterns are controlled by the regional NNW- and NE-trending conjugate zones of transpression. Gold-bearing quartz veins are located within NNW-oriented sinistral shear zones in Kurdeman gold mine area, within steeply dipping NW- and SE dipping thrusts and NE- and NS-oriented dextral and sinistral shear zones around Sukari mine area, and along E-dipping backthrusts and NW-SE and N-S fractures in Sukari granite. The high grade of gold mineralization in Sukari is mainly controlled by SE-dipping back-thrusts branched from the major NW-dipping Sukari Thrust. The gold mineralization in Sukari gold mine and neighboring areas in the Central Eastern Desert of Egypt is mainly controlled by the conjugate shear zones of the Najd Fault System and related to E-W directed shortening associated with oblique convergence between East and West Gondwana. [ABSTRACT FROM AUTHOR]

Abstract: The NE–SW trending Mubarak shear belt in the Central Eastern Desert (CED) of Egypt records the structural features of a transpression regime. Structural interpretation of satellite data and field observations indicates the presence of two episodes of deformation. The less dominant D1 deformation is related to sinistral movement along NW–SE trending Wadi Abu Dabbab shear zone and formation of F1 tight to isoclinal non-cylindrical folds and thrust fan as a consequence of transpression. The thrust fan includes ESE- to SE-dipping thrusts in the ophiolitic mélange and S- to SSW-dipping thrusts in the northern part of the metagabbro–diorite complex. The transpression-related sinistral shear regime is superimposed by the dominant D2 dextral transpression along NE–SW trending Wadi El-Umra shear zone. This dextral shearing is characterized by development of NNE- to NE-trending S2 cleavage, strike-slip duplex, NNE- and NE-trending F2 folds, and NNW-directed thrusts. These two events represent a single progressive phase associated with sinistral transpressional deformation, which is related to a younger E–W shortening event. E–W directed shortening is due to oblique convergence between East and West Gondwana along the Mozambique belt. Transpressional structures in the NE–SW trending Mubarak–Barramiya shear belt indicate highly oblique convergence leading to wrench-dominated dextral transpression and development of a major flower structure between Wadi Mubarak and Hafafit dome occupying the whole width of the CED. [Copyright &y& Elsevier]