Banca de QUALIFICAÇÃO: CARLOS RENIR SOARES DE ARAUJO

CHARACTERIZATION OF THE KARST MORPHOLOGY BETWEEN THE MUNICIPALITIES OF ALTANEIRA AND FARIAS BRITO, CEARÁ, BRAZIL

Characterization. Karst Geomorphology. Semi-arid. Paleoclimates. Mapping.

This work addresses the characteristics of the karst morphology present in the region of the São Romão Valley, between the municipalities of Altaneira and Farias Brito, State of Ceará. The region highlighted in this study is inserted in the geological and tectonic context of the northern portion of the Borborema Province, Rio Grande do Norte Domain. It is a region with a semi-arid climate, which presents a set of typically karstic forms made up of metacalcariums from the Estaterian period, such as the Lapias, which are exposed to the surface and make up the landscape of the slopes of the São Romão Valley. With the objective of characterizing the karst morphology present in the region, working on the aspects of formation, description of morphologies and mapping them. The research work began with the survey of readings, followed by three other stages, such as field research, production of thematic maps of the area and analysis and writing of the collected data. This work used bibliographic research, field research and mapping as the main actions for understanding and describing the dynamics of karst forms and processes in the region. The study area is an integral part of the sertaneja depression, with the presence of a large massif (Serra do Quincuncá), residual crests, structured in metacalcarious and a morphostructure with strong influence of fault lines in its genesis. The genesis and evolution of the karst of the region was possible by the joint action of exogenous factors, such as humidity and temperature, something that is not present in the place today. By relying only on high temperatures and low humidity levels throughout the year, the present karst morphology of the area is a reflection of a formation in past climatic conditions. The karst morphology has a characteristic genesis, requiring favorable climates, with high humidity, high temperatures and mineralogical components ideal for dissolution/erosion, such as calcite and dolomite. The most common morphologies identified in the area are part of the exogenous karst, with the presence of metacalcareous walls, Lapiás in flutings, fields of lápias and exhumed blocks.