SOURCES OF GEOMORPHOLOGICAL DIVERSITY IN THE TROPICS

Resumo

The concept of geodiversity has its roots in the fossil record as part of the Earth’s biodiversity and in the need for conservation of fossil localities and other sensitive geological sites. The geomorphological component of geodiversity is central to landscape conservation and is examined as a response to the operation of magmatic and surface processes interacting over long time periods. Differentiation of landforms can arise directly from formational processes or develop over time as result of varying sensitivity to earth surface processes. In the tropics, the susceptibility of rocks to chemical weathering is a key source of geomorphic diversity, particularly in the denudation of geologically stable terrains. The accumulation of weathering products as duricrusts, and as quartz sands can, however, can lead to reduction in both geodiversity and biodiversity, locally and regionally. Numerical methods for quantifying geomorphological diversity need to take account of these factors. The unique features of many iconic landforms also add to the difficulties of using terrain indices of geomorphic diversity derived from digital elevation models.