Contribution to the geology of Failaka Island,Kuwait: Evidence from sedimentological and petrographic data from the NE part of the island

Kuwait–Georgian archaeological work at Failaka Island showed the need for geological study. Analysis of sediments related to drinking water-collecting cisterns was performed on a Late Islamic settlement (NE part of the island) in 2018. Field sedimentological, grain size and XRD analysis of the sediment profiles showed that the shallow (about 1 m deep) cone-shaped wells are dug in the loose, porous, cross-stratified calcareous coarse-grained quartz sandstones. Three upper layers of quartz sandstones in the profile have high infiltration rate and provide a rare yet ideal material for water retention. The fourth dense layer below, composed of very fine sand and silt fraction, tends to hinder water movement and forms a relatively impermeable water-resistant surface. Thus, the distribution patterns of clay content, grain sizes and porosity of the well-hosting sediments are favourable for freshwater infiltration and harvesting. An additional petrographic analysis was conducted on different types of rocks discovered on the archaeological site, used as building material and fragments of stone artifacts to identify their origin. It was established that archaeological building material is of local origin, whereas the source rocks for stone artifacts were imported.