Neoproterozoic structural evolution of SE Sinai, Egypt: II. Convergent tectonic history of the continental arc Kid Group

Abstract

The Neoproterozoic Wadi Kid Group includes volcano-sedimentary sequences deposited in active continental margin back-arc, remnant arc and intra-arc settings. The ENE–WSW to E–W arc trend and arrangement of arc-related basins suggests subduction to the N or NNW. The four stage deformation history (events D1–D4) of the northern Wadi Kid area is described in the companion paper (part I). This contribution (part II) reveals three deformation events (D1–D3) in the southern Wadi Kid area. These three events can be correlated with D1–D3 in the northern Wadi Kid area, with differences in D1–D3 intensity and orientation patterns between the northern and southern areas. In the southern Wadi Kid area D1 probably involved NW-ward thrust stacking of beds with lesser folding effects. D2 structures include gently dipping foliation, semi-recumbent mesoscopic folds, and SSE-vergent thrust faults. D3 is a macroscopic folding event with mainly gentle upright WNW–ESE trending folds. The Quneia Diorite intruded syn-D2 and is also D3 affected. For the Wadi Kid area as a whole, recent workers interpreted D1 as the main crustal thickening event, followed by D2 gravitational collapse, regional extension and core complex exhumation. Our investigation finds both D1 and D2 to be folding and thrusting events (i.e. both convergent tectonic events) that emplaced high T schists in the north over the lower T arc metavolcanics in the south. The core complex and thrust tectonic interpreted models are both consistent with clockwise metamorphic P– T–t histories, however, they have distinct P– T–t–D diagrams.