Navegando por Autor "Auler, Augusto S."

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Livro
Espeleologia e licenciamento ambiental
(2019-10-31) Ribeiro, André Afonso; Auler, Augusto S.; Ferreira, Cristiano Fernandes; Rubbioli, Ezio Luiz; Cruz, Jocy Brandão; Reino, José Carlos Ribeiro; Piló, Luís B.; Ferreira, Rodrigo Lopes; Moura, Vitor; Cruz, Jocy Brandão; Piló, Luiz B.; Jocy Brandão Cruz
Artigo
A large Cervidae Holocene accumulation in Eastern Brazil: an example of extreme taphonomical control in a cave environment
(International Journal of Speleology, 2012-07) Hubbe, Alex; Auler, Augusto S.
Neste estudo apresentamos a descrição, cronológica interpretação tafonômica de uma acumulação notável de restos de cervídeos em um único local na Lapa Nova (Nova Caverna), uma dolomita Caverna de labirintos no sudeste do Brasil
Artigo
Silica and iron mobilization, cave development and landscape evolution in iron formations in Brazil
(2022-02-01) Auler, Augusto S.; Barton, Hazel A.; Zambelli, Barbara; Senko, John; Parker, Ceth W.; Sasowsky, Ira D.; Souza, Tatiana A.R.; Pujoni, Diego; Peñaranda, Jorge; Davis, Reed
Abstract Iron formations display some of the oldest and most enigmatic landforms on Earth, presently restricted to few areas of the planet. The original rock, the Banded Iron Formation (BIF) was formed in the Proterozoic and has been continuously weathered through a complex interplay of chemical and biological processes involving the massive mobilization of the main elements silica and iron, resulting in silica depleted (but friable) high-grade iron bodies and a Fe-rich surficial duricrust known as canga. This study presents new data and includes a comprehensive review of the existing literature, incorporating extensive data from unpublished reports and new findings. It aims to quantitatively analyze the morphology and development of porosity in iron formations both at micro and macro scales, assessing the geobiological mechanisms responsible for iron and silica mobilization and their role in the dynamics of this ever-evolving landscape. Silica leaching is the initial process of porosity generation at depth in the phreatic zone and results in a productive aquifer that contributes to the removal of solute and the generation of initial low-density zones. The development of numerous pores and voids is favored by the permeability contrast at the shallow contact zone between the canga and the weathered ore. Caves tend to occur at the base of scarps at the limit of plateaus and ridges, and tend to scale down in size away from the borders. The landscape evolves through the retreat of scarps, mostly through the collapse of cave passages. Caves exhibit a characteristic morphology that intercalates larger rooms and smaller connecting passages, suggesting that macropores started initially as isolated voids and occur either entirely in canga or in the weathered BIF, but commonly are associated with the contact between these rocks. Caves in the Amazonian Carajás region display the largest dimensional values, regardless of bedrock context. Longer caves show a larger number of connections between rooms, suggesting that the coalescence of rooms mostly through slope interflow processes is a key player in fostering the development of caves. Fractal Dimension (FD) calculated for the larger caves demonstrates that there is no relationship between lithology and FD, although values of FD vary between regions, with Carajás displaying the highest ones. Geomicrobiological processes play a major role in the mobilization of iron through Fe(III) reducing bacteria. In particular, it promotes the long-term stabilization of voids through the generation of a hardened surface that protects the walls of caves and voids from collapse. The interplay of chemical and bacterial processes allows for the generation of a highly integrated network of pores and caves that represent outlets for the removal of silica and mobilization/concentration of iron. These voids are the result of geochemical leaching and evolve synchronously with the landscape, mostly at scarp level. Such processes connect isolated pores, promote evacuation of solutes and allow for the slow lateral degradation of the landscape. This geologically slow process is now heavily affected by mining operations, which reinforces the need for searching for mitigation and/or regeneration pathways in order to preserve this unique geo-biological ancient landscape.
Artigo
Spatiotemporal distribution of invertebrate fauna in a mesovoid shallow substratum in iron formations
(2024-02-09) Dornellas, L.M.S.M.; da Silva, P.G.; Bichuette, M.E.; Auler, Augusto S.; Culver, David C.; Pipan, Tanja; Pires, Lorena Oliveira; Neves, Frederico de Siqueira
Iron Formations (IF) are among the most threatened environments due to the extensive mining activities. Mesovoid Shallow Substratum (MSS) in IF represents a poorly known subterranean environment and evaluating its fauna has the potential for expanding knowledge about the distribution of troglobiotic populations. We evaluated the spatiotemporal distribution of the subterranean fauna in the MSS of IF in Brazil. We sampled the MSS invertebrate fauna and described the community patterns of troglobiotic and non-troglobiotic species. A total of 22,821 individuals and 276 morphospecies belonging to two phyla were found: Annelida and Arthropoda. Acariformes, Diptera, Hymenoptera, Blattodea, and Collembola represented 92.2% of the individuals sampled. Nine troglobiotic morphospecies belonging to four groups were sampled: Araneae (1), Entomobryomorpha (6), Poduromorpha (1), and Pseudoscorpiones (1). We found a high compositional dissimilarity of troglobiotic and non-troglobiotic species in terms of spatial β-diversity (among MSS sites) and temporal β-diversity (among months). The observed spatial β-diversity of troglobiotic species sampled in the MSS is greater than that of non-troglobiotic species. The temporal variation is similar for both groups. The richness difference component contributed more to spatial and temporal β-diversity for troglobiotic species, while higher replacement values for non-troglobiotic species were observed. Average values of temporal β-diversity and the replacement component were greater for non-troglobiotic than for troglobiotic species, while the richness difference component had an opposite pattern. The spatiotemporal β-diversity patterns suggest a medium-to-low connectivity of invertebrate populations that colonize the MSS, favoring the adoption of strategies for conserving broader areas in the context of IF.
Artigo
Toca da Boa Vista, BA - a maior caverna do hemisfério Sul, Brasil
(Boletín Informativo de La Comisión de Geospeleología, 2003) Auler, Augusto S.; Smart, Peter L.
Este boletim é de caráter informal com o objetivo de divulgar com rapidez as atividades geoespeleológicas na região de FEALC, e neste, apresenta o artigo sobre a toca da boa vista, BA, a maior caverna do hemisfério sul, Brasil