TEXTURAL - HEAVY MINERALS CHARACTERIZATION OF FORESHORE - BACKSHORE SEDIMENTS, MARSA ALAM- WADI AL JIMAL, RED SEA COASTAL ZONE, EGYPT

Abstract

Grain size processing and heavy minerals separation carried out on 22 and 25 representative samples of foreshore and backshore sediments respectively collected from the Coastal zone between Marsa Alam and Wadi El-Jimal. The intertidal sediments are chiefly coarse-grained (15 samples), moderately (4 samples) to poorly sorted (15 samples), symmetrical (6 samples) to coarse-skewed (9 samples) and very leptokurtic to very platykurtic. The beach sediments are medium (11 samples) to coarse-grained (8 samples), moderately well to poorly sorted, symmetrical (9 samples) to coarse-skewed (11 samples) and very leptokurtic to very platykurtic. The average total heavy mineral contents in the (0.250-0.125 mm) fine sand fraction of both sediments are 28.10% and 16.90% respectively, and in the (0.125-0.0.63 mm) very fine sand fraction are 52.95% and 25.64% respectively. The heavy minerals identified are predominantly iron-bearing minerals (magnetite and goethite), titanium-bearing minerals (sphene and rutile), pyroxene, barite, biotite, plagioclase, cetrine, sillimanite, garnet, apatite, fluorite, tourmaline, topaz and olivine. The gabbroic, dolerite, basaltic rocks, alkali feldspar granites, granodiorites, tonalite, quartz diorite, monzogranite, syenogranites and metamorphic rock assemblages encountered in Wadi Alam, Wadi Samadai, Wadi Ghadir and Wadi ElJimal are the main source for the detected heavy minerals.