Sediments off the west coast of Barbados: Diversity of origins

Abstract

A multiplicity of sources is evident in marine sediments off the west coast of Barbados, W. I., where sediments and morphology of the sea floor were studied to an outer depth limit of 1,300 ft. A high percentage of carbonate material that did not form in the present environment of deposition occurs in sediments of the three sediment facies recognized in this study area. Shoreward of a depth of 70 ft., sediments of the insular shelf facies are composed mainly of modern skeletal material along with detrital deposits. Between depths of 70 and 400 ft., an area that includes two submerged reefs, sediments of the upper slope facies contain a complicated mixture of relict residual, modern organic and volcanic material. Seaward of a depth of about 400 ft. in the slope facies, sediments are composed mainly of residual material derived from submarine outcropping beds, but include some volcanic and modern organic material. The pyroclastic material in the marine sediments was derived from La Soufrière on the island of St. Vincent, which is 100 miles west and leeward of Barbados. The non-carbonate fraction of the insular shelf sands is predominantly detrital quartz. Grey discoloration in carbonate grains, which is caused primarily by the presence of diagenetic pyrite, occurs in those grains that were transported into stagnant, ponded river mouths that are common along the west coast of Barbados.