Petrology and engineering properties of rock units exposed at Sharm El Sheikh and Dahab areas, Southern Sinai, Egypt

Abstract

This article highlights on the geological and geotechnical characteristics of the outcropping units at Sharm El Sheikh and Dahab areas. These areas are representing the most attractive touristic villages along the Gulf of Aqaba at the eastern boundary of Sinai Peninsula. The work program includes 1) site collected representative samples from each exposed rock unit, 2) geological mapping by using the mosaics and recent land Satellite image, 3) in-situ tests and 4) laboratory tests. The mapped rock units of the studied area are divided into four units. The oldest unit is Precambrian granite of Heib Formation and the other three units are sedimentary and include Sharm El Sheikh, Safra and Hadamiya formations. The three sedimentary units are well presented and studied in the section of Gebel El Safra .The measured stratigraphic unit thickness at Gabal Safra is about 227 m. Sharm El Sheikh Formation is petrographically classified into arkose, sublitharenite, lithwacke, quartz arenite, quartz wacke and some other varieties as siltstone and conglomerates. The soil part of this unit is classified as poorly graded sands or gravely sands with little or no fines. The average values of the insoluble residue are 92.7%.The measured in-situ strength (by Schmidt hammer) ranges between 12 and 20 MPa. Safra Formation is petrographically classified into dolomitic subarkose, sandy dolostone and tercalations with some clastics as lithic wacke and siltstone. The in-situ strength of this unit ranges between 14 and 18 MPa. The Hadamiya Formation is alluvial and consists mainly of gravel (29.64%), sand (55.4%) and silt and clay (14.95%). The average value of the insoluble residue of the tested samples is 92.3%.