Padrões Sedimentológicos do Sistema Praia-Plataforma Continental Interna de Icapuí, CE (NE-Brasil)

Sedimentological Patterns of the Beach-Inner Continental Shelf System of Icapuí, CE (NE-Brazil)

Abstract

The aims of this study was to associate the importance of headlands in the morphosedimentary aspects of the shallow shelf in a stretch of the coast of Icapuí, state of Ceará, inserted in the Potiguar Basin. The methodology consisted of analyzing 154 samples collected in an area between Ponta Grossa and Peroba. The samples were analyzed for texture, calcium carbonate, and grains identification, for further analysis of statistical parameters. Sedimentation is predominantly of a mixed nature (carbonate-siliciclastic), with a tendency for fine to very fine sand to predominate near the coastline. In the more distant sectors (and mainly to the north and downstream of Ponta Grossa) sedimentation of coarser fractions predominates, including fragments of the Barreiras Formation. Also noteworthy is the large presence of carbonate sediments in these ultra-shallow waters, reaching values of almost 100% of CaCO3 in the shallow platform and more than 80% of CaCO3 in the beach. In this way, the geomorphic control of headlands in the adjacent offshore morphosedimentary conformation is evidenced, with topobathymetry derived from the evolution of the Potiguar Basin, sea level change and modern coastal processes (aerodynamics and hydrodynamics). Therefore, these aspects seem to favor the predominance of carbonate sedimentation, even though several points of input of terrigenous sediments on the coastline are verified (e.g., cliff erosion, dunes).

Keywords: Mixed Sedimentation; Shore Platform ; Headlands.