SEDIMENTOLOGICAL AND MORPHOLOGICAL-CHARACTERISTICS OF SOME NABKHA DEPOSITS IN THE NORTHERN COASTAL-PLAIN OF KUWAIT, ARABIA

Nabkhas in the sabkha flat of the northern coastal plain of Kuwait are generally located in areas slightly higher than the evaporitic sabkha pans, and facing the alluvium fans descending from the bordering clif fs and slopes. They are developed by the deposition of wind-driven sed iments around Nitraria retusa shrubs. The nabkhas vary in shape and si ze. However, they mostly have an elongated domal shape with an average height of 102 cm and an average length of 18 m. Three textural groups were recognized, namely, sandy nabkhas, silty sand nabkhas and sandy silt nabkhas. Detailed textural and mineralogical investigations of th e nabkha deposits revealed that they are mainly derived from the sabkh a flat sediments. Beach sands, desert aeolian deposits and dust fallou t are considered as secondary sources. Morphometric parameters, minera logic composition and textural characteristics of the studied sabkha a re presented and are thoroughly discussed. It was concluded that Nitra ria retusa shrubs are efficient horizontal sand traps for wind-driven sediments and, therefore, a thorough understanding of the development and aerodynamic behaviour of nabkha can provide useful information for the design of sustainable biological sand control measures in desert areas.