Reconstructing the Tectonic History of the Arabian–Nubian Shield in Sinai: Low-Temperature Thermochronology Implications on Wadi Agar Area

Abstract

The Arabian–Nubian Shield envelops the entire regional tectonic history from its formation during the Ediacaran to the Red Sea/Gulf of Suez rifting in the Oligocene–Miocene. The occurrence and extent of the expected successive tectonic events on Sinai basement rocks remain uncertain. Integration of thermochronological techniques with time–temperature modelling has proven to be a powerful tool for thermal-tectonic history reconstruction. Therefore, we collected representative samples from the Arabian–Nubian Shield basement rocks of the Wadi Agar area at the eastern flank of the Suez rift. Zircon fission-track data show two cooling age possibilities of Ediacaran and Devonian ages. Meanwhile, apatite fission-track data represent three cooling age spans of Carboniferous, Triassic, and Cretaceous. The integration of these data with the modelled time–temperature histories reveals four different cooling events synchronous with the regional events; (1) the Neoproterozoic post-accretion erosional event that causes near-surface rock uplift, (2) the Devonian–Carboniferous Hercynian tectonic event which affected the region with rocks exhumation of ca. 4.2 ± 1.4 km, (3) the Triassic Gondwana breakup initiation, and (4) the Oligocene–Miocene Gulf of Suez rifting which caused flanks uplift in the studied region of ca. 1.2 ± 0.4 km. The Gulf of Suez is a passive rift with a dominant mechanical component that is divided into two differently exhumed northern and southern segments, where an additional far-field thermal overprint was restricted to the southern segment.

Tectonic-Thermal Evolution of the Wadi El-Dahal Area, North Eastern Desert, Egypt: Constraints on the Suez Rift Development

“…While by the Devonian-Carboniferous time, the Hercynian (Variscan) tectonic activity developed by suturing of the Gondwana with the Laurasia [25]. This collision initiated significant uplifts and erosions in the Lower Paleozoic sequence of the NED and Sinai [2,17,38,[77][78][79]. Meanwhile, a complete succession was conserved in South Jordan and North Saudi Arabia [24,80].…”

“…The Gulf of Suez represents the northern extension of the Red Sea rift system, which is a continental lithospheric rift that developed partially into a seafloor spreading stage in its southern portion [1]. The rifting processes can be studied indirectly through the rift flanks, as any rift-accompanied activity, volcanism, and/or thermal effect will be printed on the rift shoulders [2,3]. The Suez Rift flanks are constructed from Neoproterozoic Arabian-Nubian Shield (ANS) basement rocks (Figure 1).…”

“…622-535 Ma; [8]) younger granitoids, dike suits, and volcanosedimentary succession exposures, and lesser existence of the older granitoids (ca. 753-733 Ma; [8]) and ophiolites [2,[8][9][10][11][12][13][14][15]. attention was given to the western flank of the rift [17,18].…”

“…Minerals 2023, 13, x FOR PEER REVIEW 3 of 16 different thermochronological techniques with time-temperature modeling [32,33]. Several thermochronological studies have taken place on the rift system flanks of the Red Sea, the Gulf of Aqaba, and the eastern Gulf of Suez [2,3,16,19,20,22,24,[34][35][36][37][38][39], whilst less attention was given to the western flank of the rift [17,18]. This information shortage is responsible for several uncertainties in concern to the tectonic development of the region.…”

“…This could provide a more localized source from the Afar plume through lateral migration of melts [41,44]. Low-temperature thermochronology techniques have proven to be powerful tools to address the aforementioned issues [2,3,[16][17][18]32,45]. Therefore, reconstructing the thermal-tectonic history of the area of study, which represents the ANS basement rocks in the Egyptian North Eastern Desert and central western flank of the Suez Rift (Figure 2), will provide new insights into the regional tectonic events that affected the area of study and to what extent and, furthermore, the role of Sinai triple junction or a mantle plume effect in the Suez Rift initiation.…”