Banca de QUALIFICAÇÃO: FERNANDO SÉRGIO GOIS SMITH
Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.DISCENTE : FERNANDO SÉRGIO GOIS SMITH
DATA : 08/03/2019
HORA: 16:30
LOCAL: Sala 2 - PPGG
TÍTULO:
Sedimentary Provenance Analysis and Holocene Evolution of Parnaíba River Delta Through Vibracores
PALAVRAS-CHAVES:
Parnaíba River Delta; Provenance; Sedimentology; Vibra-Core; Mineralogy; Holocene Evolution
PÁGINAS: 22
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
RESUMO:
The present work comprises the parcial results of the description of vibra cores collected in recent sediments deposited in the Parnaíba river delta, located on the border between the states of Piauí and Maranhão, in the Barreirinhas basin. Because of the low number of inhabitants and the low socioeconomic development of the Brazilian Northeast region, the Parnaíba River delta is a rare example of this environment deposit system that still presents a large part of its natural features with few human interventions. On the delta, 9 cores were collected by the method of vibration of which 5 have been described so far. A granulometric, compositional, mofoscopic and mineralogical analysis was carried out in a total of 120 samples from these 5 cores aiming to carry out a study of sedimentary provenance in the delta and identify changes in the depositional environment that may be related to the lateral migration of the main channel of the Parnaíba river and to the isolation of the western portion of the delta during the Holocene. Ascending granodecresence was observed in the four cores. At the tops, we have very fine sands or mud with high contents of organic matter and calcium carbonate (CaCO3). At the intermediary section occurs a variation between very fine sand and medium sand with present a decrease in the contents of organic matter and CaCO3. At the base occurs fine sand with low levels of organic matter and CaCO3. The transition between mudy and sandy environments occurs abruptly, however concordantly, between depths of 42 and 72 cm. The mineralogy on the basis of the cores in the western portion of the delta, close to the city of Tutoia shows great similarities with the mineralogy of the cores located in the main channel of the Parnaíba river. However, topos have significant variations indicating that in the past, the Parnaíba river deposited sediments directly in the western portion of the delta but at some point this reality has changed Possibly, in this period the main channel ran through the western portion and the great tidal channels of the delta are in fact ancient main channels that were abandoned during the ovolution of the lateral migration of the river.
MEMBROS DA BANCA:
Presidente - 2218779 - HELENICE VITAL
Externo à Instituição - LUCIANO HENRIQUE DE OLIVEIRA CALDAS - PETROBRAS
Interno - 219.901.818-05 - YOE ALAIN REYES PEREZ