The mineral composition of the mud halo of the Guyana coast is studied. Terrigenous quartz and feldspars are totally dominant in pelitic sediments of the littoral zone accompanied by terrigenous and organic calcite, variable amount of kaolinite, hydrated micas, and smectites. Authigenic accessory minerals include pyrite, Fe-Mn carbonates, goethite, single grains of magnetite and chalcopyrite. Various provenances are considered for the formation of sediments.
