The Use of the Stream Length-Gradient Index in Morphotectonic Analysis of Drainage Basins in Poços de Caldas Plateau, SE Brazil

Abstract

The Pocos de Caldas Plateau is formed by the alkaline intrusion of Pocos de Caldas and surrounding metamorphic basement. It is characterized as a remnant of the South American Planation Surface resulted from erosional events from Late Cretaceous-Paleogene transition. Pocos de Caldas Alkaline Massif (PCAM) was formed during alkaline volcanism event from the Late Cretaceous. It is located on the west side of the Mantiqueira Mountain Range, characterized by alkaline rocks and topography reaches over 1700 m high. A major feature of denudation is the development of the “circular drainage”, a particular feature of some caldera and other circular or concentric structural features. Recent tectonic movements may critically affect regional geomorphology by influencing river patterns and orientations. The morphometric analysis shows that some rivers are controlled by reactivated faults, however, in some regions the lithology has major influence in the rivers development.