Evaluation of the Crustal Features of the Gulf of Aqaba Deduced from Geophysical Data

A Z Hamouda,S El-Gharabawy

doi:10.4236/gep.2019.74003

Abstract

The Gulf of Aqaba is considered as an interesting rift system. Therefore, it is important to understand the crustal features and thickness variation along the Gulf; to be able to evaluate the effect of tectonic activities in shaping the Gulf. The obtained data were used to estimate the reliable empirical relations between the Bouguer anomalies (ΔgB) and crustal thickness (Hc) in the Gulf of Aqaba. This equation was used to calculate the depth reliefs to the Moho boundary. The output map of the Moho relief and the corresponding crustal thickness were constructed for the Gulf of Aqaba. The depth from sea level down to the Moho discontinuity in the Gulf of Aqaba varies between about 37 km in the northern deep and abruptly changes to about 28 km at the southern area, Tiran Strait. Below the central part of the gulf, a Moho depth of about 34 km is obtained. The Red Sea crust is thinner than that of the Dead Sea rift; indicating the presence of a mantel upwelling that is related to the spreading of the sea floor. The asymmetry of crustal thickness between the eastern and western borders of the Gulf of Aqaba could be attributed to simultaneous strike-slip motion. The relative displacement between the two borders is observed clearly through the sea floor and Moho discontinuity. The displacement is nearly equivalent to 0.18° (i.e. about 20.4 km) and is assumed to be achieved in about 4.08 to 3.4 million years, according to the estimated rate of the transform motion along the Gulf of Aqaba (Dead Sea transform) that is about 0.5 to 0.6 cm/y.

Highlights

IntroductionThe northern Red Sea-Gulf of Aqaba is a very interesting rift system such as the Gulf of California-Imperial Valley
The Gulf of Aqaba is composed of three deep and elongated basins, striking N20 ̊ - 25 ̊E. These basins are separated by shallow sills, and the Gulf is divided into three distinct parts
It is noticed that the northern part of the Gulf has a relatively simple bathymetry, and is dominated by the flat-bottomed Elat Deep, about 50 Km long and 3 - 8 km wide, that is considered the largest basin in the Gulf, in addition to being the shallowest

Summary

Introduction

The northern Red Sea-Gulf of Aqaba is a very interesting rift system such as the Gulf of California-Imperial Valley. These are the only two places in the world where a mid-oceanic ridge system changes into a transform system and runs into the continent. The slip rate is less than 1 cm/yr along the Dead Sea rift; while, it is about 5 cm/yr., along the San Andreas Fault (Ben-Averham 1987; Ben-Averham et al, 2005) This is reflected in the seismic activity, heat flow and magmatic activity in these regions (Hamouda, 2006; El-Bohoty et al, 2012; Hartman et al, 2014)

Methods

Results

Conclusion