Holocene evolution of the Continental Shelf adjacent to the Parnaíba Delta
Parnaíba Delta; high resolution seismic; continental shelf; equatorial margin
This research uses the integration of knowledge about high resolution seismic, bathymetry and sonography in marine areas, more specifically in the area of the Parnaiba river delta. The use of hydroacoustic methods and the integration of their data allowed to obtain images of the seabed and thus perform a subsurface recognition work of the site, which can be used in a sustainable way or solely for the knowledge and protection of the riches hidden there and thus contribute to a better understanding of the geological evolution of the Parnaiba delta, characterized as a still natural delta. The results obtained from the study of more than 580 km of seismic records allowed the visualization of several architectural elements characteristic of river systems. It was possible to identify in these records’ erosional truncation surface, paleochannels and incised valleys, which indicate an intense change in direction and local hydrodynamics. The large sedimentary contribution provided by the Parnaiba River, led to the grounding of channels in part of the platform forming incised valleys. This process of silting and complete drowning of the river channel can be identified in seismic sections on the continental shelf in front of the mouth of the Parnaiba River.