Holocene sediments in a shallow bay, southern coast of Kuwait, Arabian Gulf

Abstract

The texture, composition, distribution and origin of sediments in a shallow open bay of the northwestern part of the Arabian Gulf have been investigated. Evaluation of 67 samples shows that sediments are mostly sands and silts with large but variable carbonate contents. The bottom of the bay has a very irregular morphology with many N-S submarine ridges which could represent an older Holocene land surface. The grain size of the surficial sediments is partly related to depth. Finer sediments, in the central part of the bay, are surrounded towards the shore by coarser deposits. Two promontories strongly influence the sediment distribution. Unidirectional currents (mainly longshore currents and to a lesser extent rip currents) are the main depositional mechanisms. Shell fragments and calcareous rock fragments from wave-cut cliffs are the main components of the coarse fractions. Aragonite and high-Mg calcite are the main carbonate minerals accompanied by smaller amounts of low-Mg calcite. The main differences between the studied area and some of the other arid areas elsewhere in the southern Arabian Gulf are (1) the considerable amount of the aeolian admixture and (2) the carbonates are mostly composed of angular shell fragments.