A gravity and magnetic study of the Arba‘At Area, Red Sea Hills, Sudan

Abstract EN

Detailed gravity and magnetic measurements made in Khor Arba'at and the adjoining coastal plain region provide a better definition of the near surface geological features.

The Nakasib Shear Zone (NSZ).

which represents a reworked suture hctween two island arcs, is characterized by a gravity low and exhibits a lack of magnetic anomaly.

The edges of NSZ.

however, display magnetic anomaly associations where the shear /one rocks present a substantial magnetic susceptibility contrast with the surrounding rocks, such as ophiolites.

The post-tectonic intrusion of the Arba’at granite has a well defined gravity low which suggests a westward extension of the granite body into the shear zone rocks.

The main Arba'at intrusion is estimated to be about 6 km thick.

The coastal plain basin containing Mid-Tertiary and younger sediments appear to be laterally segmented by the subsurface relief of the Proterozoic basement.

Gravity data suggest a local thickening of sediments in the southern part of the area.

Evidence for a regional subsurfacc fault offsetting the Cenozoic sediments beneath the Recent sediments of the coastal plain is lacking.