Are any granite landscapes distinctive of the humid tropics? Reconsidering multiconvex topographies

Geomorphologists have long debated over whether certain geomorphic types of landscapes may evolve only in certain climatic conditions, with granite terrains often chosen to illustrate such climate–relief relationships. The view deeming inselberg landscapes in particular to be distinctively tropical is difficult to sustain in the light of research demonstrating both the wide global distribution of inselbergs and evident rock control on their origins and development. However, another geomorphic type of granite landscapes has emerged as possibly specific to low latitude terrains, characterized by efficient deep weathering. In the context of the ongoing debate, this paper considers the case of multiconvex topography, consisting of low hills weathered throughout, which is widely distributed in South America, Africa and Southeast Asia but not yet reported from middle or high latitudes. Multiconvex landscapes require that weathering operates efficiently in all topographic settings and that dissection proceeds to maintain relative relief. Hence they tend to be associated with areas subject to moderate uplift. There is little chance for this type of relief to survive major environmental changes towards aridity or cooling because stripping of the weathering mantle will not be compensated by saprolite renewal.