CECAV
URI permanente desta comunidadehttps://bdc.icmbio.gov.br/handle/cecav/1
Centro Nacional de Pesquisa e Conservação de Cavernas
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4 resultados
Resultados da Pesquisa
Item Natural responses of Neoproterozoic dynamic karst springs to rainfall events, São Miguel Watershed, Minas Gerais, Brazil(2024-03-03) Marques, Tássia; Galvão, Paulo; Assunção, Pedro; Pandolf, Bruno; Marshall, Peter; Paiva, IsabelKarst aquifers consist of complex networks of conduits in which groundwater flows and recharge/discharge processes are generally more dynamic than in other types of aquifers. Due to their intrinsic heterogeneity and anisotropy, monitoring, quantifying, and analysing natural responses of karst springs is an efficient tool. Unlike Cenozoic and Mesozoic rocks, in Neoproterozoic karst systems, groundwater circulates and stores generally in dissolution features known as tertiary porosity, as the rock's primary porosity is recrystallized, considered negligible. This article studies the hydrodynamics of a karst portion of the São Miguel River basin, southwest of the state of Minas Gerais, Brazil. The region is predominantly composed of Neoproterozoic carbonate rocks, dating from about 570 to 540 million years ago. During a hydrological year (2019–2020), three karst springs (S1, S2, and S3) were daily monitored through their natural responses (variations of electrical conductivity, EC, temperature, T, and discharge, Q) to rainfall episodes. The data were interpreted based on the analysis of spring hydrographs, time series, recession curves (seasonal and intra-annual), and statistics of EC, T, and Q variations. The results show the three springs generally exhibit quick flow, typically karstic, in the case of hydrosystems with a well-structured and functional underground drainage network. The time series indicate the hydrosystem drained by S1 presents slower circulation and a lower degree of linearity, resulting from the higher sinuosity of the system, while the hydrosystems of S2 and S3 have similar behaviours, of quick water circulations immediately after a rainy episode. The degrees of karstification classify S1 and S2 as complex and extensive karst systems consisting of several subsystems, and S3 as a system in which the conduit network is more developed at the upper epiphreatic zone than near the outlet.Item The paleoichnofauna in bones of Brazilian Quaternary cave deposits and the proposition of two new ichnotaxa(2023-10-22) Trifilio, Lucas Henrique Medeiros da Silva; Araújo Júnior, Hermínio Ismael de; Porpino, Kleberson de OliveiraThe Quaternary vertebrate paleontology of the Brazilian Intertropical Region is well-known, but there are only a few publications on bone ichnology. In this paper, we analyzed trace fossils in 23 bones of the Gruna das Três Cobras, Complexo Suíço, and F3 caves, which are located in Bahia and Rio Grande do Norte states, in the Brazilian Intertropical Region. We discovered gnaw marks assigned to Machichnus and bite marks attributed to Nihilichnus, as well as insect modifications referring to single (Cuniculichnus, Gunnellichnus, Karethraichnus, and Osteocallis) and multiple behaviors (Munitusichnus, and Taotieichnus). Additionally, we proposed the new ichnospecies Nihilichnus sulcatus n. isp. (bite mark) and Cuniculichnus cascudoi n. isp. (insect feeding mark). Regarding the predation/scavenger marks, Protocyon troglodytes was the probable primary modification agent, but some traces may also be attributed to Smilodon populator and Caiman latirostris. Cuniculichnus, Karethraichnus, Munitusichnus, and Osteocallis are attributed to dermestids, whereas termites probably produced Gunnelichnus and Taotieichnus.Item Geoparks: Pathways to Internalize Sustainable Development in the State of Bahia, Brazil(2022-04-09) Pereira, Ricardo Galeno Fraga de AraújoThe State of Bahia is located in the northeast region of Brazil. It has a population of almost 15 million people, 25% of which live in the Metropolitan Region of Salvador — RMS, the capital city, which accounts for over 40% of the state’s gross domestic product — GDP. Bahia has seven geopark proposals made by the Geological Survey of Brazil — CPRM, and it is the Brazilian state with the largest number of geoparks proposals in the country. All these geoparks proposals listed by CPRM for Bahia are in the countryside, more than 200 km away from the RMS, and are mostly related to geomorphological aspects. Four of these proposals are located in Chapada Diamantina, an ancient diamond mining region that is marked by mountain ranges and plateaus, sculpted in low metamorphosed Proterozoic sedimentary rocks, with caves, waterfalls, and relevant mining heritage. Considering the geoparks’ proposals for the state, Serra do Sincorá, São Desidério, Morro do Chapéu, and Alto Rio de Contas already count with geological heritage inventories, but the latter proposal lacks officially constituted organizations focused on its implementation. The CPRM’s geopark proposals for Bahia will be assessed here, envisioning that geoparks can be a pathway for sustainable countryside development in the state, helping in the distribution of its GDP, spreading scientific knowledge, reinforcing local identities, promoting the United Nations — UN Sustainable Development Goals — SDG, and fostering healthy lifestyles.Item Controversies and hidden risks in biodiversity offsets in critically threatened Canga (ironstone) ecosystems in Brazil(2022-11-09) CARMO, FLAVIO FONSECA; KAMINO, LUCIANA HIROMI YOSHINOCanga, or ironstone, ecosystems are hotspots of old-growth plant diversity and highly specialized cave inver tebrates. These ancient metalliferous habitats are amongst the most threatened ecosystems because of the destruction caused by large-scale iron ore mining. International debate on biodiversity offsets is increasing because these mechan isms are seen as tools for potentially balancing economic de velopment with conservation biodiversity. Leading mining companies worldwide, including some of the largest iron ore producers in Brazil, are signatories to offset principles and best practices that aim to achieve no net loss of habi tats, species or ecosystem functions. We aimed to analyse whether Brazilian legal requirements for biodiversity offsets result in the achievement of conservation outcomes or in elevated threat of extinction in canga ecosystems. We eval uated technical reports that support decision-making re lated to environmental licensing for iron ore mining and specific offset proposals linked to the Atlantic Forest Act. We found a relevant net loss in canga ecosystems and ob served shortcomings related to the equivalency and trans parency of offset principles. These deficiencies are mainly related to lax norms and regulations and the absence of an integrated database for accessing information on environ mental licensing processes. We argue that both policy flaws and low engagement by the Brazilian mining industry in implementing offset principles have increased the threat of extinction in canga ecosystems.