Lithospheric delamination in models of post-collision tectonics in the Egyptian Eastern Desert and Sinai: Claims versus evidence

Abstract

Lithospheric delamination has been proposed to have occurred in the aftermath of the ∼630 Ma collision-related lithospheric thickening of the Arabian Nubian Shield (ANS) in numerous studies of post-collision volcanism, granite plutonism, and post-collision uplift, erosion and extension of its northern parts (the Egyptian Eastern Desert, EED). In this contribution we assess the strength of the evidence presented for the role of delamination in the EED from previous studies. The strongest evidence in favour of delamination in the EED lies in the detailed models of uplift coupled with syn-extension volcanism in the North Eastern Desert (NED) of the EED. Key differences between the NED and CED (Central Eastern Desert) to its south, may be explained in an EED delamination model that involves syn-collision delamination-assisted gravitational collapse in the CED, with migration of the delamination northwards into the NED, where it was post-collisional in timing. The initial point of detachment of the delaminated lower crust and lithospheric mantle may have been at or near the boundary between the CED and the SED (the Southern Eastern Desert) in the EED.