Banca de DEFESA: KATIA DE JULIO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : KATIA DE JULIO
DATA : 28/02/2018
HORA: 09:00
LOCAL: Auditório do LGGP II
TÍTULO:

Origin, Evolution, Characterization and 3D Modelling of Eolian Systems in the Rio Grande do Norte Coast

PALAVRAS-CHAVES:

Post-Barreiras, dunes, GPR, dating, cronostratigraphic framework, deposicional systems, radar facies, bounding surfaces.

PÁGINAS: 113
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
RESUMO:

This work presents the results of a survey on deposits of the Post-Barreiras informal unit and dunes in the Pitangui region, eastern coast of Rio Grande do Norte. In the case of Post-Barreiras deposits, GPR (Ground Penetrating Radar) and core samples were used to calibrate radargrams with sedimentary facies and to obtain data on depositional systems - internal structures, paleocurrents and 3D geometries; dates helped to set up a chronostratigraphic framework of these deposits, never before dated in the region. The relationship of these deposits and correlated deposits of the north and northeast of Brazil and with the relative global sea variation curve were evaluated. The results indicate the predominance of continental fluvial systems, with lateral and frontal sand bars migration in wide and shallow channels, dated 52,000 ± 4,381 and 54,687 ± 5,688 years BP, and eolian deposits, dated 83,842 ± 7,383 and 90,109 ± 8689 years BP, which is similar to related units in sites of the state of Paraíba, the coastal zone of São Luís, Maranhão and Northeast of Pará. The strata of eolian origin are the oldest deposits dated of eolian origin from Pós-Barreiras unit. The research done with GPR on parabolic fronts of a dune field, supported with field data, aimed the imaging of eolian systems and their stratigraphic evolution, achieved with the interpretation of radar facies, which represent the broad internal structure of sand dunes, and radar surfaces, which represent bounding surfaces with a chronological character. In this way, the stratigraphic context and the definition of the types of eolian systems present in the area, previously scarcely defined, became clearer. Sedimentary analyzes identified heavy minerals present in these dunes and allowed to explain that the origin of the long and high amplitude reflector patterns in the active dune foresets is due to the presence of heavy minerals, especially the opaque hematite, ilmenite and magnetite. Further studies could explain the reasons for the significant difference in migration (paleo)direction between Post-Barreiras sandstones and the present dunes in the region.

MEMBROS DA BANCA:
Interno - 1315614 - DAVID LOPES DE CASTRO
Presidente - 1161652 - FRANCISCO PINHEIRO LIMA FILHO
Externo à Instituição - LEAO XAVIER DA COSTA NETO - IFRN
Externo à Instituição - LUCIANO HENRIQUE DE OLIVEIRA CALDAS - PETROBRAS
Interno - 2042405 - MOAB PRAXEDES GOMES