Morfologia e aspectos geométricos das cavidades de ambientes cárticos na Serra da Bocaina em Canaã dos Carajás-PA

Abstract

Serra da Bocaina is inserted in two Morphostructural and Morphoclimatic Units: the Dissected Plateau of Southern Pará; and the Peripheral Depression of Southern Pará. At the top, hills with concave and convex slopes are often interrupted by lateritic cover ruptures.These ruptures mark well the boundaries of the residual plateau in the form of imposing erosive escarpments, which often harbor caves in ferrous rocks. Formed by a deep weathering of lateritic lands, due to the dissolution and leaching processes, the caves are a karst geoform that can present several morphological and geometric configurations, associated with its dominant genesis. In this perspective, this research aimed to make an analysis of the morphological and geometric patterns of the 235 caves located in the Serra da Bocaina, Canaã dos Carajás, State of Pará, correlating them with the hipsometry, lithotypes, relief shapes, speleometry and the morphodynamic processes of relief. Thus, the 235 Serra da Bocaina caves are located mainly in the low slope 56% (131), 29% in the high slope and 16% in the average slope. Three geometric patterns were defined (Simple Rectangular Rectangle, Simple Rectangular Triangular and Simple Spherical), but the geometric classification is not possible to be defined in most of the studied cavities, as it is misshapen.The caves of composite typology occur predominantly in ferricrete. In turn, most of the caves with simple typology are inserted in Jaspelito and canga. The caves with PH above 50m have composite typology. While the simple typology predominates between 5 and 30m. Thus, it is evident that the pattern concentration tendencies are certainly conditioned by the textural and structural arrangement elements of each geological substrate, as well as their behavior against the weather and hydrodynamic action.