The changing geomorphology of the humid tropics

Abstract

It is debatable whether tropical geomorphology is intrinsically different from the geomorphology of other places. The traditional geomorphology of the humid tropics had certain expectations with regard to landforms and processes. A number of case studies over the last three decades, however, using new concepts and field and laboratory techniques, have changed such expectations. This paper primarily examines the research themes of the last ten years or so, identifies the major trends, and attempts to predict areas where interest is expected to concentrate in near future. The following topics among the current research trends are highlighted: geochemical erosion, movement on tropical slopes, rivers in the tropics, tropical landforms, hydrology and sedimentation in the rainforest, denudation efficiency in the humid tropics, the Quaternary evolution and changes, and the applied side of tropical geomorphology. Clearly, the landforms and geomorphological processes in the tropics are dependent only partially on climate, but to greater extent on neotectonism, lithology, episodic and catastrophic events such as tropical cyclones, and above all on anthropogenic alterations of the landscape. A wide variety of landforms and processes are found in the humid tropics, and generalisations are extremely difficult. In the next century geomorphological studies in the tropics are likely to develop along certain lines. Environmental investigations will form a major component along with the study of postulated sea level rise. Current major research trends will undoubtedly continue, but increasingly through a multidisciplinary and multipeople approach. Large-scale investigations involving pantropic correlation of past events, such as synchronised large floods, will grow. Use of new research tools such as satellite imagery, various dating facilities, etc. will become common and expected. It seems likely that the arrival of so much information will modify mainstream geomorphological and sedimentological theories or will provide these with a tropical version.