Banca de DEFESA: ISAAC VINÍCIUS FAGUNDES DE SOUZA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : ISAAC VINÍCIUS FAGUNDES DE SOUZA
DATA : 29/06/2016
HORA: 09:00
LOCAL: Auditório do Departamento de Geofísica (DGEF)
TÍTULO:

Analisys of the neogene structural influence in the context of the Barreiras aquifer – Catu River Horst - RN

PALAVRAS-CHAVES:

Barreiras Formation Aquifer; electroresistivity; Structural Compartmentalization; aquifer geometry; Catu River Horst – RN.

PÁGINAS: 105
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
RESUMO:

The geometric characterization of sedimentary aquifers has been increasingly required in the well rent studies needed for the supply of urban and rural communities. The hydraulics parameters such as flow and hydraulic transmissivity are related, among other factors, with the thickness of the aquifer, emphasizing the importance of regional hydrogeophysical characterization and consequent compartmentalization of aquifer.  In this context, this research consists in a analisys of the Neogene Structural influence in the Barreiras Aquifer, adopting as the study area the Catu River basin - RN, southern coast of the Rio Grande do Norte state. The methodology used was based on remote sensing techniques using the shuttle radar imagery, analysis of well profiles, and geolectric inverse models “thickness x resistivity”, from reinterpretations of geoelectrical soundings. Thus, the hydrogeophysical profiles was obtained to identify variations of satured thickness, possible signatures in the local hydrogeological potentiometry and identify the most promising areas for future water exploitation.

The regional structural characterization was realized initially by geomorphological analisys (topography and hydrography), considering the SRTM data processing with resolution of 75 x 75m. After the gridding and interpolation of total SRTM data, was defined a representative regional component, highlighting the regional W-E gradient towards the coast. The residual map was obtained from the subtraction of the total component in relation to regional component to highlight some local features that is not related with the regional components, showing around 81 topographic lineaments. In addition, the image hillshade of the SRTM data processing allowed the identification of 1107 drainages lineaments and 1235 standardized drainages lineaments, after, this results was plotted in rose diagrams. In this hydrographic analisys, were used different types of azimuthal illumination and vertical exaggeration, to highligth the drainages lineaments. The joint analysis of the geomorphological data enabled the development of a synthesis map with the characterization of morphotectonic alignments mainly trending N50º-60ºE and N40º-60ºW. 

The resistivity survey, was performed to study specified local where wells information were insufficient or non-existent  in order to enable the obtaining of a geometry model of the local saturated zone. In this context, were considered reinterpretations of sixteen geoelectrical soundings with the aim to identify values of  satured thicknesses and top of the hydrogeoeletric basement of the Barreiras Aquifer, associated to carbonate sequence non-outcropping. The maximum spread of the electrodes was 1.2 km (AB / 2 = 600m) and the arrangement used was Schlumberger. Considering the morphotectonic framework reported and the available well and geoelectrical data, was drawn up four hydrogeophysical profiles designed to characterize faults through throws configuration in subsurface of some of these morphotectonic alignments. Final results give throws faults showing values ranging from 10 to 44 meters, especially in the northeast portion of the basin area, associated with variations in the thickness of the Barreiras Aquifer. The integration of hydrogeological and geophysical data revealed associations between geoelectric mapping and potentiometric map highlighting promising areas for groundwater exploitation. Finally, through a 3D block diagram, there was the direct influence of Neogene structure in the context of Barreiras Aquifer revealing hydrogeological basement rebates associated with increased thickness of the aquifer.

MEMBROS DA BANCA:
Interno - 1315614 - DAVID LOPES DE CASTRO
Presidente - 1714488 - LEANDSON ROBERTO FERNANDES DE LUCENA
Externo à Instituição - NATALINA MARIA TINOCO CABRAL - SGB