Paisagem geomorfológica e potencial geoturístico do carste de Natividade e Chapada da Natividade, sudeste do Tocantins

Abstract

From the perspective of karst geomorphology, this research aims to contribute to the production of knowledge about the relief on carbonate rocks located in the municipalities of Natividade and Chapada da Natividade, southeastern Tocantins. To this end, it aims to characterise the main karst features of that region, making considerations about the stage of landscape conservation and the tourist potential of the regional karst. Specifically, an attempt was made to compartmentalise the studied area, describing the primary morphologies, producing at the end an exploratory map of karst phenomena on a scale of semi-detail (1: 50,000). Furthermore, the modes of human occupation were analysed and interpreted, correlating the landscape spectrum, in the broad sense, to the impacts caused by the karst features themselves. We sought to demonstrate the geotouristic potential of the karst through the choice of LIGeoms - Places of Geomorphological Interest, as they bring together scientific, educational, contemplative, environmental and cultural aspects. To respond to proposed objectives, preliminary mapping of the drainage network, slope, and altimetric elements supported the interpretations regarding the possible areas for recharging and discharging the karst system. The author used studies on geological inputs to understand the morphostructural conditioning factors of the most important courses in the area for compartmentalisation. The morphological features were interpreted from the karst literature. The exploratory map was made using specific semiology based on several bibliographies. The same was refined with radar images from the ALOS satellite, Palsar sensor, satellite Sentinel 2A, MSI (Multispectral Instrument) sensor, and several field works, vital throughout the research. To better interpret and understand compartments, topographic profiles were made, aiming to demonstrate the contact between the positive karst morphologies and non-carbonate lithologies. Still, in this context, it was made a diagram block highlighting the contact pad. In the context of landscape changes, maps of land cover and usage were made over 10 years. So, images from Landsat-5 and Landsat-8 satellite were used for the years 2010, 2015 and 2020. In a complementary way, the descriptions made in loco followed specific field sheets for the cerrado phytophysiognomy and the karst morphologies themselves, later synthesised on a board with images of all the points visited. In turn, points with geotouristic potential were also organised on a panel for better spatial understanding. Two caves were characterised in two LIGeoms specific conditions, establishing their speleotourism potential, defined based on evaluation sheets, suitable for this type of study. Free software was used to assist in compiling and producing the primary geoinformation materials, emphasising QGIS, versions 2.18.0 and 3.4.5. Finally, it was understood that the karst of Natividade and Chapada da Natividade contains invaluable geological, hydrogeological, geomorphological, geotouristic, educational and cultural activities. Therefore, scientific research is necessary for that area, making this study a reference for future work.