GEOMORPHOLOGY OF THE BRAGANÇA COASTAL ZONE, NORTHEASTERN PARÁ STATE

Abstract

The area can be subdivided into three main geomorphologic compartments: (1) alluvial plain, with fluvial channels, levees and flood plain; (2) estuarine plain, with an estuarine channel subdivided into estuarine funnel segment, straight segment, meandering segment and upstream channel and; (3) coastal plain, with salt marshes (inner and outer), tidal flats (supratidal mangroves, intertidal mangroves and sandy tidalflats), chenier sand ridges, coastal dunes, barrier-beach ridges and ebb-tidal delta environments. The Braganfa coastal zone is an active sedimentary region, which has been developed largely since the higher Holocene sea level (5,100 years BP). It has been concluded, based on geomorphology, lithostratigraphy and sedimentary processes, which the coastal plain has evolved from mangrove progradatipn, protected by dune-beach ridges with associated fluvial-estuarine-tidal channels. Therefore, the sedimentary model shows a complex depositional system, which is influenced by a broad tidal range.