Morphological Features and Sedimentological Aspects of Wadi Al-Kura, North of Jeddah, Western Coast of Saudi Arabia

Raised carbonate-siliciclastic terraces, alluvial terraces, sabkhas, coral reef flat and topographic high hills formed of crystalline rocks are the characteristic landforms identified from the satellite images and field investigation of wadi Al-Kura. These geomorphic units reflect both the climatic and structural conditions that prevailed in the Late Quaternary period. The exposed successions differ considerably with respect to recent carbonate sedimentation in the other different areas. It exhibits an intimate association of pure carbonates in the form of reefs, mixed siliciclastic-carbonate and pure siliciclastics, mainly in the form of alluvial fans. The region thus offers an opportunity to determine the factors which control generally rapid transitions from one mineral facies to another. Three cycles of sedimentation have been documented. These cycles reflect tectonic effects and see level changes. Climatic phases from semi-arid to humid are deduced.