Caracterização das morfologias cársticas do metacalcário do Vale do São Romão, Ceará-Brasil

Abstract

This study resulted in the characterization of karst morphology in the Vale do São Romão region, situated between the municipalities of Altaneira and Farias Brito in the state of Ceará. The region is part of the geological and tectonic context of the northern portion of the Borborema Province, within the Domain of Rio Grande do Norte. It exhibits a semi-arid climate, featuring typical forms found in metalimestones, such as exposed lapiaz, which collectively shape the landscape of the São Romão Valley. With the aim of characterizing the aforementioned features in the region, this study seeks to understand the aspects of their formation and evolution, providing a description and mapping of these features. The research methodology is based on a review of existing literature, fieldwork, and mapping, supporting the understanding and description of the dynamics of the forms and processes within the studied lithology. The study area is an integral part of the sertaneja depression, characterized by the presence of a large massif (Serra do Quincuncá) and residual ridges structured in metalimestones. The morphostructure exhibits a strong influence of structural lineaments. The genesis and evolution of the karst in this region occurred through the combined action of exogenous factors, such as humidity and temperature, conditions that are not present today. Given the high temperatures and low humidity levels throughout the year, the karst morphology in the region reflects formation under past climatic conditions. These features have a specific genesis, requiring favorable climates characterized by abundant moisture, high temperatures, and ideal mineralogical components for dissolution/erosion, such as calcite and dolomite. The most common morphologies identified in the area are part of the exogenous karst, including cut walls, fluted lapiaz, lapiaz fields, and exhumed blocks. Additionally, endokarst features are present, including caves and limestone conduits.