Banca de DEFESA: PEDRO GONÇALVES DE NOVAES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : PEDRO GONÇALVES DE NOVAES
DATA : 28/02/2020
HORA: 09:00
LOCAL: INSTITUTO DE GEOCIENCIAS DA UFBA
TÍTULO:

Ostracodes of the Tauá member, Candeias formation lower cretaceous of  the Recôncavo Basin: taphonomy, paleobiogeography end paleoecology

PALAVRAS-CHAVES:

Microfossils, Taxonomy, Paleoenvironment, Biostratinomy, Andar Rio da Serra

PÁGINAS: 51
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
SUBÁREA: Geologia
ESPECIALIDADE: Geologia Ambiental
RESUMO:

Based on the study of taxonomy and taphonomy of ostracod fossils as well as extensive bibliographic review, the characterization of paleobiogeographic and paleoenvironmental aspects of the Tauá Member, Candeias Formation, in the Recôncavo Basin, Bahia state, was carried out. The material used as a base for this study is a fossil content present in a paleontological collection that belongs to Petrobras. This content is from 25 selected wells, which were drilled by Petrobras and are distributed along the basin. Seven oyster taxa from the Local Andar Rio da Serra (Eocretaceous / Berriasian), which are from a biozone called Theriosynoecum varietuberatum varietuberatum (NRT-002), were identified: Cypridea ambigua, C. cf. Cypridea primaria, C. sellata, C. trinodosa, Reconcavona imitatrix, Theriosynoecum varietuberatum proximum and T. varietuberatum varietuberatum. They are typical of the subzone denominated C. cf. Cypridea primaria (NRT-002.2). The taphonomy was described based on aspects of ostracod valves, such as: (I) degree of fragmentation; (II) degree of disarticulation; (III) degree of dissolution; (IV) colouring and (V) occurrence of mineralization. It was observed that the majority of microfossils showed little or no fragmentation and disarticulation, in addition to the absence of dissolution, suggesting a low-energy paleoenvironment, with little transport and rework. Mineralizations were also registered, referring to the fossil diagenesis, mainly represented by pyritization and hematitization. The colours of the shells were compared with studies that associate them with the interpretation of the thermal history and maturation of organic matter. Moreover, ostracodes with dark colours may be related to the presence of oil in the rock in which they are present. In addition, a possible fauna zoning was observed between T. varietuberatum proximum and C. ambigua, based on the geographic distribution of the wells where they were found, possibly conditioned by tectonic-structural factors and / or physical-chemical factors. The lithological information and the fossils of exclusively non-marine individuals characterize the Tauá Member with continental sedimentation, typically lacustrine, generated under anoxic conditions. For this reason, the information obtained through this research can also contribute to the characterization of the evolution of the rift phase in the Recôncavo Basin.

MEMBROS DA BANCA:
Presidente - 019.448.195-68 - ALTAIR DE JESUS MACHADO - UFBA
Interno(a) - 1212266 - RICARDO PIAZZA MEIRELES
Externo(a) à Instituição - HELISANGELA ACRIS BORGES DE ARAUJO