Intervenções Antrópicas na Geomorfologia do Estuário do Rio Capibaribe e seus Reflexos na Sedimentação Recente

Abstract

The paper aims to analyze how the anthropic intervention in geomorphology Capibaribe estuary, with evolution of the city of Recife, caused possible modifications in recent sedimentation pattern in lower and middle of the Capibaribe estuary -PE. Historical map surveys of the Recife city were carried out together with the National Museum of Rio de Janeiro, Museum of the Recife City Hall, CONDEPE / FIDEM and satellite images of Google Earth. To identify the possible changes in the sedimentary pattern, two cores were sampled in the lower (T2) and middle estuary (T5) regions, in which the sedimentation rate was determined by the 210 Pb method and sedimentological analyzes. The T2 core (158 cm) recorded a sedimentation rate of 0.45 cm.year -1 and three sedimentary facies with different characteristics. Unit 1 (before to 1812 to 1856) indicated events occurring before the first major anthropogenic intervention for the lower estuary. Unit 2 (1856-1972) registered the beginning of the expansion works of the Recife’s Port, with increases in the percentages of the sand fraction and decreases in the mud percentages. Finally, Unit 3 (1972-2012) presented the anthropic influence in the estuary, with high sedimentation of the fine fraction of the sediment. The medium estuary (178 cm) recorded a sedimentation rate of 0.52 cm. -1 and four units with different sedimentary characteristics. Unit 1 (previous to 1812) presented characteristics of mangrove environment. Unit 2 (1812-1937) presented a slight increase in sand percentages, possibly associated to the processes of urban expansion and monoculture of sugarcane. Unit 3 (1937-2004) presented the highest percentage of sand, reflecting the intensification of the city’s urban expansion processes. Unit 4 (2004-2012) presented increases in finer sedimentation, probably a consequence of mangrove reforestation projects in the estuary conducted by the Recife City Hall. Anthropogenic intervention in the Capibaribe estuary was the main factor influencing the recording of different sedimentary units in the estuarine system.