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Relative sea-level curves for the mid-to late-Holocene have been proposed for eight different sectors along the Brazilian coast. This paper aims to review the data used to construct the curves proposed for two sectors, the ParanaguA and Canankia regions in southeast Brazil. More specifically, we analyze the palaeo-sea-level indicators (vermetid tubes, shells, wood fragments and shell-midden deposits) related to (1) the sea-level maximum of the mid-Holocene and (2) the two secondary oscillations that would have occurred between 4100-3800 years B.P. and 3000-2700 years B.P. The sedimentary deposits of the coastal plain as well as vermetid datings suggest a mid-Holocene sea-level maximum between + 3.5 and +4 m. The great majority of the indicators used to infer the secondary oscillations in previous studies were derived from shell middens. Besides being unreliable palaeo-sea-level indicators. these data also showed inconsistencies that undermine the existence of such oscillations. The plot of all the data derived from vermetid samples found along the Brazilian coast also indicate a rather smoother sea-level fall in the last 5100 years. 0 1997 Elsevier Science B.V.

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Based on the integration of geological information, the pollen record, radiocarbon data, and modern mangrove distribution, this paper proposes a model of evolutionary development for mangroves on the Brazilian Braganc¸a Peninsula driven by relative sea-level changes from the middle to late Holocene. After a postglacial relative sea-level rise (RSL), the mangrove habitats on the Braganc¸a Peninsula began to develop at about 5100 years BP close to the current RSL, originating in the middle of the peninsula. Between 1800 and 1400 years BP, this littoral area underwent a maximum RSL fall of 1 m below the current one, followed by a gradual RSL rise until 1000 years BP, when the modern RSL was reached. Between 5100 and 1000 years BP, the RSL of the Braganc¸a coastline was probably never higher than 0.6 m above the present level. The first Holocene mangrove forest (5100 years BP) in this region disappeared from the plains due to RSL fall and was replaced by herbaceous vegetation (Cyperaceae and Poaceae).

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A regional marine reservoir correction (ΔR) of 33±24 14C yr for southern Brazil was obtained from 6 marine shell samples collected in the states of Santa Catarina and Paraná. This work also presents a ΔR estimation of 8±17 14C yr for the southern and southeastern Brazilian coast from the states of Rio de Janeiro to Santa Catarina, obtained by including 7 ages published in previous works. The high variability of R in modern and Holocene samples from the Brazilian coast is also discussed.

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