SEISMIC ARCHITECTURE OF THE TIDAL CHANNELS SYSTEM GALINHOS-GUAMARÉ (NE OF BRAZIL) AS EVIDENCE OF THE HOLOCENE SEA LEVEL CHANGES
Shallow seismic; spit; paleochannels; Holocene
The interpretation of shallow seismic data allows the identification of subsurface features, which in turn contributes to understanding the geological evolution of a region. Therefore, it is necessary to recognize the chronostratigraphic limits, the seismic reflector termination patterns, the seismic facies analysis, and the external geometry of the packages.This study has as main objective to study the geological evolution of the tidal channel system Galinhos-Guamaré as a response to the Holocene sea level changes.The data were acquired using a Subotton Profile type chirp, model X-Star 3200-XS, EdgeTech and processed with ReflexWin 6.0.5 software. The frequencies used ranged from 0.4-4kHz, 0.5-4.5kHz and 0.5-7kHz. The results revealed the presence of four horizons (SF01, SF02, SF03 and SF04) representing, from the base to the top, the boundaries between the seismic units U01, U02, U03 and U04, respectively. The main horizons were SF02, SF03 and SF04, the first two with erosive surfaces characteristics and the last one representing the surface of maximum flood, probably related to the gradual variation of sea level during the Holocene. These horizons were observed in all the lines acquired in this part of the area, representing therefore an important geological significance for the formation of this region. Additionally, paleochannels and subaqueous dunes were identified. The changes in the sedimentation patterns observed in the seismic record show the different depositional systems formed in the area along the Holocene