Large-scale geological structures of the Egyptian Nubian Shield

Abstract

Integration of potential field- and structural data make it possible to trace surface and subsurface large-scale geological structures of the Egyptian Nubian Shield (ENS). Obtained results indicate that the Northern Eastern Desert (NED) of the ENS is dominated by relatively younger (c. 580 Ma) E–W and NE–SW trending extensional structures that were controlled by the evolution and retreat of the Cadomian Arc. Density of such extensional structures increases with depth as displayed by the potential data. The prevailing structural trends in the Central Eastern Desert (CED) are NW–SE and WNW–ESE. Both trends are highly prompted by the timing of deformation upon the Najd Fault System, and are themselves dissected by a relatively younger NE–SW shearing trend. Lineament density in the CED is subordinate for both subsurface and near surface structures. The South Eastern Desert exhibits compressional and extrusion-related structures of two main prominent trends; WNW-to-NW (to the western part) and the N-, NNE- to NE (to the eastern part). The previously mentioned Neoproterozoic trends are remarkably influenced by the Oligocene–Miocene Red Sea-Gulf of Suez rift related fractures in the vicinity of the rift shoulder. The remarkable change in trends and densities of structural trends, especially in the NED, is interpreted in terms of concealing of the older structures by the younger extensional structures which in turns reflect an N-ward progressive deformation in the entire ENS. Gravity data are more appropriate in delineating the structural trends compared to the magnetic data which are largely affected by lithological variations and/or alteration zones and magnetic mineralogy.

An integrated remote sensing, petrology, and field geology analyses for Neoproterozoic basement rocks in some parts of the southern Egyptian-Nubian Shield

“…The geologic map of the area (Fig .2 ) shows master lineaments of NW and NE trends, with a prominent N–S trend in the western part of the area; the NE trend is the youngest. It was affected by the Marsa Alam Shear Zone trending from NW to SE 32 . Wadi Samadai-Um Tunduba district is covered mainly by Neoproterozoic basement rocks.…”

Direct Detection of Groundwater Accumulation Zones in Saprock Aquifers in Tectono-Thermal Environments

“…Two major units comprising the ancient metasedimentary sequence, pre-Pan African (2.8 ± 1.3 Ga), and Pan African Older Granites PAOG (600 ± 1500 Ma) dominate the Precambrian terrain. Structural records on the rocks suggest that they have undergone polyphase deformation (resulting in their folding, faulting, foliation, and shearing) via Pan-African orogenic activities [34,35]. The rocks in the Obudu Plateau are dominated by high-temperature and pressure metamorphic rocks such as migmatites, gneisses, schists, amphibolites, cataclasites, and quartzites that have undergone amphibolite to granulite metamorphism [35].…”

Gravity-magnetic appraisal of the southern part of the Cauvery Basin, Eastern Continental Margin of India (ECMI): evidence of a volcanic rifted margin

“…The present study area is mostly covered by sediments, except in western parts; therefore, the structural features and basement geology remain elusive. The potential field data have been effectively used for structural studies attempting to better understand basement geometry (Castro et al, 2014;Curto et al, 2014;Essa et al, 2018;Eldosouky and Mohamed, 2021;Hamimi et al, 2023) and mineral investigations (Blundell et al, 2019;Eassa et al, 2022) in different parts of the world, especially over sediment-covered terrain. However, insights into the shallow crustal structure and deep crustal architecture based on high data density and systematic coverage of the ground gravitymagnetic data are limited, especially for the southern part of the Cauvery Basin.…”