Análise sedimentar de testemunhos por vibração de um canal de maré a oeste do rio Parnaíba (PI-MA)

Abstract

The Parnaiba River Delta, located on the Piaui- Maranhão border, presents its feature preserved, being ideal for conducting research in Geology. This paper is about to identify changes in the sedimentary deposition based on the energy of the sediments, which could be related to some changes in the Parnaíba River flow. The techniques used were sedimentary and petrophysics analysis of two vibra cores (VC-03 and VC-10) collected in a tidal channel in the west side of the Parnaiba River. Spectral analysis of Gamma Ray, pictures and stratigrafhy description were carried out in all the cores, while granulometric, compositional, morfoscopic, mineralogical and porosity analysis were carried out in 4 cm to 4 cm. In the results, carbonate and organic contents were associated to fine granulometry and this indicates that VC-03 was less compacted regarding to VC-10. The mineralogy presented on the base of the cores were similar with some other cores located in the west portion of the Delta, studied in other papers, while the top of them were similar to other cores located in the east portion. So, we can conclude that some changes happened in the Parnaiba River flow over time, changing the sedimentary source.