Mineralogical characteristics of surface sediment in Sulaibikhat Bay, Kuwait

Surface sediment samples were collected from 35 locations in Sulaibikhat Bay, Kuwait. Grain sizes, total organic carbon (TOC), carbonate and mineralogical data were determined. The geographical distribution of these parameters, and their relationships with each other are described. Grain-size analysis showed a high positive correlation between clay minerals and organic matter (measured as TOC), but a high negative correlation between clay minerals and carbonate content (measured as CaCO3). Grain-size analysis also showed that the southeastern part of the Bay, which contains muddy sediments with a predominant silt fraction,. also has the highest clay content. The calcium carbonate in the sediments, particularly in the western part of the Bay, is composed of sand-sized biogenic calcareous fragments of aragonite. There appears to be a positive relationship between coarse-grained sediments and the biogenic content of bottom sediments in the Bay. This study shows that there is an abundance of carbonate, clay minerals, feldspar, pyrite, gypsum and muscovite in different particular parts of the Bay. An abundance of pyrite close to the Ghazali outfall with low oxidation-reduction potential (ORP) values (48.0-188 mV) may be associated with the presence of hydrogen sulphide and pyrite in the sediments suggest the possibility that reducing conditions prevail because of sulphate reduction associated with the decomposition of organic matter. The high correlation of pyrite with TOC supports the view that the presence of pyrite is an indicator of the presence of sewage waste under anaerobic conditions.