Perfis de relevo e índices geomorfométricos na análise evolutiva do escarpamento da Serra dos Órgãos (RJ)

Abstract

This article aims to investigate the evolution of the Serra dos Órgãos escarpment in the last thousands of years through morphological and geomorphometric analyzes, carried out through topographic profiles, longitudinal drainage profiles and Chi factor (χ) values. These analyzes sought to assess the degree of “instability” of the drainage channels and the migration direction of the drainage dividers. Relief and longitudinal profiles of the fluvial channels carried out indicate that basins that drain into the interior plateau have a greater number of local base levels and were interpreted as being in a stage of greater erosive “imbalance” than the basins on the steep front. Recent tectonic events can be suggested from the profiles elaborated, directly influencing the geomorphological and geomorphometric characteristics of the study area. Meanwhile, profiles of channels located on the oceanic slope of Serra dos Órgãos reflect channels in advanced degrees of erosive processes, given by the concave shape of the profiles, typical of “balanced” rivers; however, by the values of the Chi factor (χ), it was observed that these drainages have a greater erosive potential of the headwaters than the basins facing the reverse plateau, thus indicating mechanisms of drainage rearrangements and the migration of the divider.