Seasonal compositional variations in intertidal carbonate sediments from Kubbar island-Kuwait

Kubbar Island is considered to be one of the most spectacular places in Kuwait, because it is a natural habitat for a variety of resident and migratory birds, a nesting ground for turtles, and a unique place for the growth of coral reefs. The carbonate sediments along the shores are derived primarily from coral colonies and other organisms living in the waters around the island, such as molluscs, algae, echinoderms and foraminifera. This research is based on sampling the intertidal carbonate sediments in the eight main compass rose quadrants: (south, north, east, west, northeast, northwest, southeast and southwest) during different seasons (autumn, winter, summer). Forty eight sediment samples were collected and analyzed petrographically. The purpose of this study was to elucidate the effect of weather variations such as prevailing wind direction, temperature, and water salinity on the coral colonies and the nature of the accumulated sediments along the shores of Kubbar Island throughout the different seasons.Grain size analysis indicates that most of the grains are of coarse sand size, with very coarse sand size as the second most abundant grain size. In addition, most of the samples are poorly sorted and strong coarse skewed and coarse skewed. All samples indicate short distance of transport, high wave action, and fast deposition. Although some variations exist, indicating higher wave action during October 2001 (Autumn) and varied wave action during January 2003 (Winter), the results also indicate differences in grain size along the shores of the island, which are dependent on the prevailing wind direction and wave action. These grain sizes are: granule, very coarse sand, coarse sand, and medium sand. Petrographic study indicated variation in micritization and burrowing extent of the carbonate constituents between the seasons, where micritization and burrowing of bioclasts were higher during January 2003 than the other seasons. In addition, the presence of halite, aragonite, high-Mg calcite, and gypsum crystals as cements and/or detached crystals was higher during October 2001 and June 2002. All the data regarding grain size analysis and petrography indicated the influence of weather and environmental parameters on the nature of the accumulated sediments along the beaches of Kubbar Island