Banca de DEFESA: JULIANA GUZMÁN GONZÁLES

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : JULIANA GUZMÁN GONZÁLES
DATE: 27/02/2023
TIME: 13:30
LOCAL: ambiente virtual (remotamente)
TITLE:
KEY WORDS:

Aptian; Alagoas Stage; Northeast Brazil; Ostracodes; Foraminifers; Transitional Environment

PAGES: 131
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUMMARY:

The Araripe, Tucano Norte and Jatobá Mesozoic basins represent a branch of the South Atlantic Rift aborted in the early Aptian. The post-rift phase, which corresponds to the Alagoas Local Stage, Ostracoda Biozone 011 (Aptian), is recorded in the Araripe Basin by the Santana Group, constituted from base to top by the Barbalha, Crato, Ipubi and Romualdo formations. In the Tucano Norte and Jatobá basins, the Marizal Formation is correlated with the Barbalha Formation, and excepting the Ipubi Formation the other units with same name and correlated to those of the Santana Group are recorded. Six well cores and fifteen outcrops were lithologically characterized and sampled, resulting in more than 100,000 ostracod specimens and more than 9,300 foraminifer specimens along the post-rift sequence from the three studied basins. The microfossils recovered from the Araripe Basin presented better preservation, abundance and diversity compared with the Tucano Norte and Jatobá basins, providing a more detailed Ostracoda taxonomy that, integrated to the Foraminifera occurrence allowed the biostratigraphic and palaeoenvironmental refinement of the Santana Group, base for the posterior correlation with the other basins. Twenty-five ostracod taxa were identified, including the proposal of five new species: Damonella pumila, Pattersoncypris cucurves, Pattersoncypris kroemmelbeini, Ilyocypris coimbrai e Rhinocypris spinata. The Pattersoncypris micropapillosa Zone (OST-011) was described and divided into the subzones Pattersoncypris cucurves (OST-011.1), Pattersoncypris cucurves-Neuquenocypris berthoui (OST-011.2), Damonella grandiensis (OST-011.3) and Pattersoncypris crepata (OST-011.4). Two biostratigraphic intervals of planktic foraminifers were identified allowing the international calibration of the ostracod subzones, the Early Aptian Leupoldina cabri Zone contents the OST-011.1 and OST-011.2 subzones, and the upper Late Aptian Hedbergella infracretacea–Microhedbergella miniglobularis composite zone correlated to the OST-011.4 subzone. During the Aptian, the Araripe Basin evolved from a transitional to a marine environment, recording the Early Aptian “Batateira Estuarine System”, followed by a continental progradation represented by the “Barbalha Fluvial System” up to a new transgression originating a bayhead delta. In the lower Late Aptian, the “Crato Bay” developed, that posteriorly retrograded forming a restricted marine ramp under extreme aridity and the precipitation of the “Ipubi Salt”. The last depositional phase took place during the upper Late Aptian with the full installation of the sea on the “Romualdo Outer Ramp”. Lithologically and biostratigraphically it is possible to correlate the Santana Group strata and the post-ritf units of the Tucano Norte and Jatobá basins, from the analyses of macro and microfacies and of the ostracods and foraminifera occurrence.

COMMITTEE MEMBERS:
Externo à Instituição - CRISTIANINI TRESCASTRO BERGUE - UFRGS
Interno - 2653353 - EDISON VICENTE OLIVEIRA
Presidente - 2182604 - ENELISE KATIA PIOVESAN
Interno - 1800053 - JOSE ANTONIO BARBOSA
Externo à Instituição - JOÃO CARLOS COIMBRA - UFRGS
Externo à Instituição - MITSURU ARAI - UNESP