EM - Escola de Minas
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/6
Notícias
A Escola de Minas de Ouro Preto foi fundada pelo cientista Claude Henri Gorceix e inaugurada em 12 de outubro de 1876.
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2 resultados
Resultados da Pesquisa
Item Post-glacial permian debris flow deposits and their paleoclimatic implications (Mariana Pimentel paleovalley, southern Paraná Basin).(2020) Coitinho, Júlia dos Reis; Kern, Henrique Parisi; Cagliari, Joice; Lavina, Ernesto Luiz Correa; Girelli, Tiago Jonatan; Tedesco, Julia; Lana, Cristiano de Carvalho; Silveira, Ariane Santos daThe end of the Late Paleozoic Ice Age was followed by a global warming climate. This climate transition is characterized by, beyond other aspects, a decrease in the intensity of physical weathering, characteristic of arid conditions, and an increase in the intensity of chemical weathering. In the southern Parana ´ Basin, the post-glacial onset and intense record of “Pedra-Areia” diamictite within the Mariana Pimentel paleovalley was likely controlled by warming climate conditions and mark a period of intense rainfall and slope instability. To test this hypothesis, we have performed facies and sequence stratigraphy analysis on cores located within the Mariana Pimentel paleovalley, and U–Pb-Hf investigations to acquire sediment provenance information. Diamictite deposits were produced by debris flow processes, which transported regolith from the valley wall to the bottom, eroding and incorporating mud and peat when reaching the bottom of the valley. The local source of sediment is explained by the sedimentological characteristics of the diamictite and zircon provenance studies. These deposits are preserved within the transgressive system tract and the abundant deposition was controlled by increasing temperature and humidity, and thus the increase in chemical weathering on the walls, forming the regolith. The development of more humid and warmer climatic conditions, contrasting with the cold and dry climate of the glacial period, was an important control over diamictite deposition.Item Provenance and paleogeography of the Southern Paraná Basin : geochemistry and U\\Pb zircon geochronology of the Carboniferous-Permian transition.(2019) Tedesco, Julia; Cagliari, Joice; Chemale Júnior, Farid; Girelli, Tiago Jonatan; Lana, Cristiano de CarvalhoThe Carboniferous-Permian transition of the intracratonic Paraná Basin (S Brazil) includes important evidence of the climate change, tectonics, and paleogeographic configuration of SW Gondwana. During this period, the Late Paleozoic Ice Age (LPIA) was in its final phase in the Paraná Basin, producing a temperate-tropical climate through the transition to the Permian. UPb laser ablation ICP-MS detrital zircon dates and whole-rock geochemistry of rocks from the upper Itararé Group (Carboniferous) and the lowermost Rio Bonito Formation (Early Permian) in the southern Paraná Basin are determined to characterize the sedimentary-dispersal patterns of the source area and glacial paleoflow. Geochemistry proxies suggest that the studied units experienced different degrees of weathering, with the Itararé Group's units forming in an arid environment. The overlying Rio Bonito Formation's units were deposited under hotter and more humid climate conditions. The Late Carboniferous to Early Permian units showed similar zircon-age distribution patterns, with a Neoproterozoic main peak from the Uruguayan Sul-Riograndese Shield. A lack of Mesoproterozoic sources in the studied samples indicates that this area of the Paraná Basin probably did not receive sediments from the African side during the Late Carboniferous as previously described. This result suggests a more complex system in which ice caps and small ice sheets dominated the glacial environment during the Late Carboniferous in this segment of SW Gondwana.