ON-LAND MANIFESTATION OF ALONG STRIKE TRANSITIONING OF THE RED SEA FROM CONTINENTAL RIFTING TO SEA FLOOR SPREADING USING AEROMAGNETIC, SATELLITE GRAVITY, AND REMOTE SENSING DATA

Abstract

:This doctoral dissertation examines the region between Ad Damm Fault Zone (AFZ) and the Fatima Fault Zone (FFZ) and harrat Rahat in the western Arabian Shield. The area of deformation under consideration exhibits a combination of brittle structures associated with Red Sea activity during the Cenozoic. These structures have overlaid ductile structures formed during the Precambrian. The volcanic rocks that formed during Cenozoic in the Harrats region are believed to potentially serve as the future route for the Red Sea floor spreading center. This project uses a combination of different geophysical and remote sensing methods separated as follows; Aeromagnetic studies have examined the on-land manifestation of the transitioning of the Red Sea from sea floor spreading to a continental rift. It indicated that there are evidence of reactivation: (1) the AFZ and FFZ largely control the old-drainage system. (2) Sharp difference in the elevation of the Red Sea topographic escarpment across the AFZ. (3) NNW- to NW-trending mafic dike swarms intrude the Precambrian crystalline basement rocks in Jeddah and Asir terranes. Gravity studies examined gravity anomalies and differences of upper and lower crust, subcontinental lithospheric mantel, and asthenosphere structure across the on-land manifestation of this transition. This study is the first attempt to measure the depth of Moho and LAB using a 2D model beneath AFZ and FFZ . The Results from this project modeling showed that the average thickness of the crust beneath the AFZ and FFZ is ~28 km and that of the upper crust is ~12 km. and showed thicker crust (~32 km) beneath the AFZ and the thickness of lithosphere beneath the AFZ and FFZ to be between ~58 km and ~68 km. Remote sensing studies have been used to map the Red Sea related brittle structure that follows the Cenozoic volcanic rocks. The information of these studies is compounded into three chapters in this dissertation. The project three indicated that there is a domal topographic vent trending N-NW which characterized late stage continental drift. This research conclude that there is a possible pathway for a new sea flood spreading center a long AFZ and across Harrat.