Logo do repositório
Tudo no RIUFPA
Documentos
Contato
Sobre
Ajuda
  • Português do Brasil
  • English
  • Español
  • Français
Entrar
Novo usuário? Clique aqui para cadastrar. Esqueceu sua senha?
  1. Início
  2. Pesquisar por Autor

Navegando por Autor "CHEMALE JUNIOR, Farid"

Filtrar resultados informando as primeiras letras
Agora exibindo 1 - 2 de 2
  • Resultados por página
  • Opções de Ordenação
  • Carregando...
    Imagem de Miniatura
    ItemAcesso aberto (Open Access)
    Evaluation of two genera of benthic foraminifera for down-core paleotemperature studies in the western south atlantic
    (2006) COSTA, Karen Badaraco; TOLEDO, Felipe Antonio de Lima; PIVEL, María Alejandra Gómez; MOURA, Candido Augusto Veloso; CHEMALE JUNIOR, Farid
    In this study we have compared the oxygen isotopic composition of two genera of benthic foraminifera (Uvigerinaand Cibicidoides) from core-top samples with modern oxygen isotopic composition of seawater (d18O). Based on a new relationship between d18O and salinity for the mid-latitude western South Atlantic, we estimated the isotopic composition of equilibrium calcite (d18Oeq) using two different equations: (1) O'Neil et al. (1969), modified by McCorkle et al. (1997) and (2) Kim & O'Neil (1997). When using (1), the small difference between d18Oeq and d18O of Uvigerina suggests that this genus precipitates its shell close to equilibrium with ambient seawater. The d18OCibicidoides data are 0.82 ‰ lower than the predicted (equilibrium) oxygen isotopic composition. Conversely, using (2) the Cibicidoides d18O data show excellent agreement with the oxygen isotopic composition predicted from d18O and water temperature while Uvigerina d18O data are 0.69 ‰ higher than predicted oxygen isotope equilibrium values. Based on the evidences presented here and on the results from previous studies we suggest using the genus Cibicidoides and applying Kim & O'Neil's (1997) equation for down-core paleotemperature investigations. In the absence of enough Cibicidoides specimens we suggest using Uvigerina d18O data and applying a correction factor of -0.69 ‰.
  • Carregando...
    Imagem de Miniatura
    ItemAcesso aberto (Open Access)
    Strontium isotope stratigraphy of the Pelotas Basin
    (2014-03) ZERFASS, Geise de Santana dos Anjos; CHEMALE JUNIOR, Farid; MOURA, Candido Augusto Veloso; COSTA, Karen Badaraco; KAWASHITA, Koji
    Strontium isotope data were obtained from foraminifera shells of the Pelotas Basin Tertiary deposits to facilitate the refinement of the chronostratigraphic framework of this section. This represents the first approach to the acquisition of numerical ages for these strata. Strontium isotope stratigraphy allowed the identification of eight depositional hiatuses in the Eocene-Pliocene section, here classified as disconformities and a condensed section. The reconnaissance of depositional gaps based on confident age assignments represents an important advance considering the remarkably low chronostratigraphic resolution in the Cenozoic section of the Pelotas Basin. The recognition of hiatuses that match hiatuses is based on biostratigraphic data, as well as on global events. Furthermore, a substantial increase in the sedimentation rate of the upper Miocene section was identified. Paleotemperature and productivity trends were identified based on oxygen and carbon isotope data from the Oligocene-Miocene section, which are coherent with worldwide events, indicating the environmental conditions during sedimentation.
Logo do RepositórioLogo do Repositório
Nossas Redes:

DSpace software copyright © 2002-2025 LYRASIS

  • Configurações de Cookies
  • Política de Privacidade
  • Termos de Uso
  • Entre em Contato
Brasão UFPA