Intemperismo em rochas graníticas: mudanças paleoclimáticas no Pico do Jabre - PB.

Abstract

The granitic reliefs are present in the different morphoclimatic domains of the planet. However, its exposure is intensified in tropical regions, in Brazil these landscapes are commonly found in the northern Northeast, more precisely in the province of Borborema as a result of the Brasilian orogeny and tectonism, which caused the emergence of massifs and inselbergs in the landscape. Thus, understanding that the Pico do Jabre is a residual granite massif and is inserted in the province of Borborema, this research intends to understand the processes that originated the formation of this relief as a granite landscape. Therefore, the exhumation of these bodies was intensified by the occurrence of weathering and erosion processes along the Cenozoic, during the intense rainfall of the humid tropical climate, which provided the transport of the sediments that once covered the granite bodies, providing the flattened surfaces of the country depression. Thus, the Etchplanation theory explains that the origin of granitic reliefs is mainly composed of saprolithic reliefs composed of boulders and slabs in different morphologies, which act as geomorphological indicators exposing that they were associated with very humid environments. In these reliefs it is possible to find different stages of slab development such as pre-exfoliation, alteration mantle and exhumed blocks. In the external structures of the inselbergs, different forms of weathering occur, such as tafoni, dissolution basins and flutes. All these features are now exhumed due to the entrance of the semi-arid climate in the region where erosive processes resulting from Pediplanation prevail.