Holocene coastal evolution of the Northern Rio Grande do Norte coast, NE Brazil.

Stattegger, K., Caldas, Lhdo and Vital, H. (2006) Holocene coastal evolution of the Northern Rio Grande do Norte coast, NE Brazil. Journal of Coastal Research . pp. 151-156.

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Abstract

Sedimentological and geochronological studies were carried out along the north coast of Rio Grande do Norte state, NE Brazil, between Ponta dos Tres Irmaos and the spit of Galinhos to reconstruct the Holocene coastal evolution of this area. Sedimentation during the Holocene has been controlled mainly by the variation of sea level, longshore currents and the advance and westward propagation of active dunes along this semiarid coast. A new sea-level curve could be constructed based on AMS-(14)C datings; of beachrock and lagoonal sediments and on careful elevation measurements. Plant remnants and bivalve shells found in the paleo-lagoon close to Sao Bento and Caicara 3 metres below the modem sea-level were dated at 7000 cal yr BP. Passing its actual position at 6500 cal yr BP sea level reached the Holocene highstand 1.2m above the modem mean level at 5900 cal years BP as documented by non-recrystallized bivalve shells from beachrock and one shell midden. Sea level dropped afterwards to its present position as can be observed from elevation and age of regressive deposits. Secondary oscillations could not be detected during the regression. The semi-enclosed lagoon of Sao Bento experienced episodic marine incursions controlled mainly by the advance of active dunes that ceased the connections between lagoon and open sea. ne last marine incursion occurred at 3580 cal yr BP. In contrast, the lagoonal system of Galinhos and Galos has remained active since the sea level reached the actual position for the first time at 6500 cal yr BP.

Document Type: Article
Keywords: sea-level curve beachrock lagoon radiocarbon dating
Research affiliation: Kiel University
Refereed: No
ISSN: 0749-0208
Date Deposited: 12 Jan 2012 05:05
Last Modified: 23 Sep 2019 22:01
URI: http://oceanrep.geomar.de/id/eprint/16023

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