Tracing the legacy of past semiarid morphodynamics in multiconvex tropical rainforest morphology in the Guiana Shield of Suriname

Abstract

A comprehensive survey of landforms, soils, geology and heavy mineral analyses in traverses across the tropical rainforest-covered Upper Suriname drainage basin shows that the prevailing multiconvex morphology conceals evidence for duricrusted colluvial slopes. They testify of pedimentation processes in past semi-arid climate conditions in the presence of mafic rocks with duricrust caps in the headwaters of the tributary creeks. In areas underlain by different types of granites and high-grade metamorphic rocks etchplain characteristics prevail. Previous studies underestimated the important role of lithology in morphological processes. The multiconvex landforms also conceal dissected remnants of higher-level river terraces deposited during semi-arid climate intervals under a continuous uplift regime, as evidenced by their heavy mineral assemblages.