Avaliação geológico-geotécnica e análise cinemática da Cachoeira do Mascate como subsídio ao ecoturismo em Coromandel, Minas Gerais

Abstract

The municipality of Coromandel, situated in the Triângulo Mineiro and Alto Paranaíba Mesoregion of Minas Gerais, boasts several natural tourist attractions, including numerous waterfalls. This undergraduate final project presents a geological-geotechnical evaluation of the Mascate Waterfall, a key geo-attraction in the region, and examines its implications for regional ecotourism. The rock massif at the waterfall is composed entirely of quartzites from the Chapada dos Pilões Formation (Canastra Group) of the Brasília Belt and displays varying degrees of weathering. It features incipient metamorphic foliation, with planes oriented at 210°N and dipping between 16° and 54°. The slope of the waterfall has a direction of 045°N and an average dip of 75°. Four families of discontinuities were identified, namely: Family 1 (F1), with E-W orientation and planes dipping to NW (direction 351°N); Family 2 (F2), with NNW-SSE orientation and planes dipping to NE (direction 070°N); Family 3 (F3), with NE-SW orientation and planes alternating dips between NW (direction 308°N) and SE (direction 148°N); and Family 4 (F4), with WNW-ESSE orientation and planes that vary their dips between NE (direction 018°N) and SW (direction 202°N). According to the Rock Quality Designation (RQD) index, the quality of the massif is classified as "Regular." Based on the Rock Mass Rating (RMR) index, the massif is classified as "Reasonable" (Class III). Kinematic analyses indicate the potential for various types of failures: wedge (29%), direct toppling (26%), flexural toppling (3%), oblique toppling (1%) and planar (9%). Planar failures are primarily controlled by discontinuities oriented approximately in the NW-SE direction with sub-vertical dips. Failures by direct and oblique toppling occur along the planes of the metamorphic foliation. The Safety Factor of 1.37 indicates stable conditions of the waterfall slope concerning different types of failures. However, periods of intense rainfall between November and March can cause greater slope instability, increasing the risk of failure. The base of the waterfall is surrounded by numerous fallen boulders, showcasing signs of gravitational mass movements. To reduce potential geological risks at Mascate Waterfall, it is recommended to implement two simple measures: (i) install informational signs regarding the risk of falling rock blocks and (ii) advise visitors to the waterfall to plan their visits during the dry season, from April to September.