GEOESPELEOLOGIA
URI permanente para esta coleçãohttps://bdc.icmbio.gov.br/handle/cecav/2
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Resultados da Pesquisa
Item ESTUDOS DE VALES SECOS EM ÁREAS CÁRSTICAS: REVISÃO E POSSIBILIDADES(2022-06) Nogueira, Adivane Morais; Uagoda, Rogério; Caldeira, DandaraO carste apresenta regiões de conexões entre os sistemas fluviais e cársticos o fluviocarste, dispondo de feições típicas, como os vales secos. Tais feições vêm sendo estudadas de diversas formas para contribuir no entendimento da dinâmica geomorfológica do carste. Este estudo visa fazer uma revisão sobre vales secos em sistemas cársticos, tendo em vista observar o potencial científico destas áreas para diversas aplicabilidades. A revisão utilizou como principal forma de busca a plataforma Web Of Science (todas as bases), abrangendo o período entre 1945-2020, que abordavam sobre tais feições, com o uso das seguintes palavras-chave: karstic valley, dry valleys, blind valley, relict valley, ancient valley, fossil valley, solution valley, paleovalley e paleokarst valley, resultando em vinte e sete trabalhos, com diversas propostas de análise, evidenciando os fatores envolvidos na dinâmica fluviocárstica. O levantamento permite observar que são poucos estudos considerando a extensão de ocorrência de rochas carbonáticas no mundo, havendo concentração das pesquisas no continente europeu. No Brasil, apesar de dispor de regiões carbonáticas e das várias áreas mapeadas com ocorrência de cavernas, principalmente no bioma Cerrado, não há pesquisas sobre o tema, mesmo que viabilizem a identificação dos fatores que influenciam evoluções dos sistemas fluviocársticos.Item Sedimentary records in dry karstic valleys: The case of Mambaí, central Brazil(2023-08) Nogueira, Adivane Morais; Caldeira, Dandara; Uagoda, Rogério; Mendes, Leonardo Chaves; Pupim, Fabiano N.Karstic areas in Central Brazil show significant depositional and erosive facies placed within abandoned dry valley-systems and associated with fluviokarstic dynamics. These valleys have distinct depositional characteristics that offer sedimentary records of both past climatic events in the region and its current fluviokarstic system. The purpose of this paper is to point out and characterize such sedimentary packages, protected by dry valleys that were deposited up until the fluviokarstic transition, thus enabling the correlation of such sediments to past climatic events. The study is based on a combination of geomorphic and sedimentological analyses through the employment of multiple techniques, such as mineralogy, geochronology, stable isotopes, and granulometry, to the analysis of our case studies. These are the three dry valleys around the Ventura, Pedras and Extrema rivers, which in turn comprise the River Vermelho Basin, northeastern Goiás State. Our results suggest that the valleys contain fluvial deposits remnant from the transition of superficial fluvial flow to the underground karstic system. Records provide a general view of the depositional stages placed before and up until the period of fluvial capture in terms of their morphology, dynamics, and sediment architecture. OSL ages indicate that fluviokarstic processes had been in operation since 23 Ka, when the oldest river capture was found to have occurred. Depositions occurred in a reasonably continuous manner, mainly during the last 3.5 Ka, and concentrated around relatively dry and wet events, exhibiting typical depositional gaps in fluvial environments. Consequently, no relationship between the depositions and paleoclimatic events were observed for the analyzed fluviokarstic system.Item Sedimentary records in dry karstic valleys: The case of Mambaí, central Brazil(2023-08) Nogueira, Adivane Morais; Caldeira, Dandara; Uagoda, Rogério; Mendes, Leonardo Chaves; Pupim, Fabiano N.Karstic areas in Central Brazil show significant depositional and erosive facies placed within abandoned dry valley-systems and associated with fluviokarstic dynamics. These valleys have distinct depositional characteristics that offer sedimentary records of both past climatic events in the region and its current fluviokarstic system. The purpose of this paper is to point out and characterize such sedimentary packages, protected by dry valleys that were deposited up until the fluviokarstic transition, thus enabling the correlation of such sediments to past climatic events. The study is based on a combination of geomorphic and sedimentological analyses through the employment of multiple techniques, such as mineralogy, geochronology, stable isotopes, and granulometry, to the analysis of our case studies. These are the three dry valleys around the Ventura, Pedras and Extrema rivers, which in turn comprise the River Vermelho Basin, northeastern Goiás State. Our results suggest that the valleys contain fluvial deposits remnant from the transition of superficial fluvial flow to the underground karstic system. Records provide a general view of the depositional stages placed before and up until the period of fluvial capture in terms of their morphology, dynamics, and sediment architecture. OSL ages indicate that fluviokarstic processes had been in operation since 23 Ka, when the oldest river capture was found to have occurred. Depositions occurred in a reasonably continuous manner, mainly during the last 3.5 Ka, and concentrated around relatively dry and wet events, exhibiting typical depositional gaps in fluvial environments. Consequently, no relationship between the depositions and paleoclimatic events were observed for the analyzed fluviokarstic system.