Clay minerals in the sediments around the Andaman Islands

Abstract

Clay minerals in the eastern side of Andaman Islands consist of montmorillonite, kaolinite, illite and Fe-rich chlorites while on western side they consist of illite and Fe-poor chlorite with minor kaolinite and montmorillonite. These assemblages have different provenances. The Andaman sea clays are derived largely from the sediments transported by the Irrawady river, while the western side shelf sediments(on the Bay of Bengal side) are derived from the weathering products of the rocks on the Island proper and the slope samples show contribution from the Ganges. Distribution of detrital minerals such as quartz and feldspar support the above conclusions. The 2 distinct clay mineral provenances result because the Andaman Islands appear to be a barrier to the mixing of the 2 clay mineral suites.