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.
Navegar
2 resultados
Resultados da Pesquisa
Item Sedimentary facies and depositional model of the Lower Cretaceous Quiricó Formation (Sanfranciscana Basin, Brazil) and their implication for the occurrence of vertebrate fauna at the Coração de Jesus region.(2021) Cabral, Victor Carvalho; Mescolotti, Patricia Colombo; Varejão, Filipe GiovaniniThe Coração de Jesus region, northern Minas Gerais state, Brazil, is highly relevant in the Sanfranciscana Basin context due to the presence of titanosaurs, abelisaurids, and noasaurids. However, there is a poor stratigraphic constrain of the occurrences and few paleoenvironmental investigations in the area. Herein, a detailed sedi- mentologic and stratigraphic investigation of the fossiliferous succession is conducted to position the vertebrate assemblage in the stratigraphy. The sedimentary rocks are interpreted as part of the Quirico ́ Formation (Areado Group), representing the thickest occurrence of the unit (ca. 56 m) to the north of the Abaet ́e sub-basin. There, two main sedimentary successions are recognized, with the lower succession dominated by mudstone facies, and the upper succession dominated by sandstone facies. Vertebrate fossils and trace fossils of the species Taenidium barretti, Skolithos isp. and Arenicolites isp. are recorded uniquely within the lower succession, where wetter environmental conditions prevailed. The sedimentary succession is interpreted as a lacustrine system with increasing influence of eolian processes, which suggests an intensification of the aridity in the region during Lower Cretaceous.Item Sedimentological characteristics and geochemistry of lake waters of the Rio Grande basin, west of Bahia State, Brazil.(2016) Santos, Gisele Barbosa dos; Castro, Paulo de Tarso AmorimThe lacustrine system of the Rio Grande basin is placed where it gathers singularities from both geological and climatic points of view. In order to understand the origin and dynamics of this system, a faciological description of the deposits from two lakes considers both textural and mineralogical elements via XRD analyses. This was followed by a chemical analysis of a dozen lakes’ water, in order to standardize the evolution of the lowlands which form the lakes. The hydrochemical data revealed two trends: one group of lakes presented sodium and base, and the other group calcium and acid. Both these groups also presented some differences in their sediment characteristics, registering round pebbles, a higher percentage of sand and presence of mica in one of the lakes, contrasting with the muddy texture with predominance of quartz and kaolinite in the other lake. Such results allowed the proposition of two evolutionary models for the lakes of the São Francisco Lowlands, which share the same climate; evidence that the other landscape elements affect the system’s dynamics. One of the models is represented by lakes that evolved from little permeable sedimentary rocks. These rocks, however, are more fractured, favouring the lakes area expansion and more water permanence with recent links to the river network. On the other proposed model, the lakes evolved from permeable but less fractured carbonic rocks with rapid vertical water infiltration and less water permanence, which reflects more atmospheric than lithological influence in their geochemical characteristics. This study provides important information for the comprehension of this landscape evolution.