Geological evolution of Nile Valley, west Sohag, Upper Egypt: a geotechnical perception
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ORIGINAL PAPER
Geological evolution of Nile Valley, west Sohag, Upper Egypt: a geotechnical perception El-Sayed Sedek Abu Seif 1,2
Received: 16 December 2014 / Accepted: 21 May 2015 # Saudi Society for Geosciences 2015
Abstract Based on distinct variations of textural characteristics, stratigraphical relationships and mineral composition of clastics sedimentary sequence (coarse aggregates) in west Sohag, Upper Egypt had been classified into six individual geological evolutionary stages. These stages were controlled mainly by geomorphology, paleo-climatic conditions, and regional and local tectonic events. In west Sohag, Upper Egypt, the suitability of the Oligocene–Pleistocene natural coarse aggregates have been examined in terms of pavement materials in a sub-base consideration. Depending on textual characteristics and mineral composition, these natural coarse aggregates indicated three distinct stages of geological evolution of the Egyptian Nile Valley. These aggregates are classified as well-graded gravels (GW) and distinguished by cubical shape with sub-angular to sub-rounded edges, as well as characterized by a relatively high abrasion resistance. This leads to a suitability of these natural aggregates in being used as a subbase pavement course for higher shear strength, exhibiting a less fatigue life. The total estimated volume of these coarse aggregate is 2060.41 million m3. This volume of natural coarse aggregates can be dry sieved and crushed to produce base and surface pavement courses.
Keywords Natural coarse aggregates . Textural characteristics . Sub-base course . Nile Valley . Upper Egypt
* El-Sayed Sedek Abu Seif [email protected]; [email protected] 1
Faculty of Earth Sciences, King Abdul Aziz University, Jeddah, Saudi Arabia
2
Geology Department, Faculty of Science, Sohag University, P.O. Box 82524, Sohag, Egypt
Introduction The geological evolution of sedimentary rock units of the studied area (Sohag Governorate, Upper Egypt) can be considered as a thumbnail of the geological evolution of the Nile Valley especially in the period ranging from Post-Eocene to recent. The evolution of the geological history in the study area has been influenced mainly by paleo-climate, local and regional tectonics, and paleo-geomorphology. Climatic indicators point to a cyclic climatic evolution from humid, semiarid to arid conditions. The depositional features as well as mineral composition and aerial distribution of Post-Eocene clastic sedimentary sequence (coarse aggregates) in the studied area had been controlled mainly by these cyclic paleoclimatic conditions and tectonic events. Aggregates represent a very important and effective component of all construction materials, so that, it is essential to evaluate the main effective characteristics of these aggregates through standard tests. Frequently, the rock units in the Egyptian Nile Valley nearly are consisting of sedimentary rocks. So in the non-basement complex areas the pavement materials with high quality can be rarely found to use as natural mate
