The physiographic significance of conglomeratic sediments and associated laterites in valleys of the Darling Plateau, near Harvey, Western Australia

Abstract

Abstract The distribution of remnants of a system of conglomeratic sediments is described in the Harvey district of southwestern Australia. A study of their relationship to the major physiographic elements and to laterite gives rise to certain suggestions regarding landscape development in the southwestern margin of the Western Australian Precambrian Shield. A tentative correlation, based largely on comparable lithology and physiographic setting, places these materials in the Mesozoic. The distribution of sediments bears only slight relationship to the present drainage. They were emplaced in a prior valley system and have been dismembered in the development of the present drainage system. All major elements of the landscape, including parts of the Darling Scarp, have been subjected to deep lateritic weathering. Lateritized remnants of the sediments progress from the upland surface to well down into the valleys and onto the Ridge Hill Shelf, which flanks the Darling Scarp. Caution is needed in placing late...