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1 May 2006 Holocene Development of Coastal Wetland at Maracas Bay, Trinidad, West Indies
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Abstract

Studies on Holocene sea level change along the coast of northeastern South America can assist in understanding how the region's coastal environments might respond to future sea level change. A freshwater wetland along a wave-dominated pocket bay yielded a 980-cm-long sediment core, which records sediment and vegetation change over the past 7000 years. Above basal sand, peaty mud <450-cm depth is overlain by mangrove peat extending <100 cm and dark, peaty freshwater mud <35 cm. Three radiocarbon dates provide a chronological framework and estimate rates of sedimentation. Loss-onignition analysis shows a shift from basal silicates to organic matter at 4000 YBP that indicates a reduction in marine influences and the establishment of a mangrove habitat. Rhizophora dominates the fossil pollen record. Spores of the tree ferns Cnemidaria and Cyathea indicate an adjacent humid forest whereas Polypodium-type spores and Cyperaceae pollen in the upper part of the core indicate freshwater conditions. The reduction in the sedimentation rate from 1.99 mm y−1 before 4000 YBP to 1.05 mm y−1 after 4000 YBP reflects reduced delivery of external sediments to the wetland and the addition of authocthonous organic matter, whereas the further reduction to 0.61 mm y−1 after 3000 YBP suggests declining rates of peat formation and reduced sediment inputs from the forested watershed. We conclude that the stratigraphy and plant succession was the result of long-term building of a beach ridge. Brackish water peat and then freshwater peat formed behind the bar.

Eugene K. Ramcharan and John H. McAndrews "Holocene Development of Coastal Wetland at Maracas Bay, Trinidad, West Indies," Journal of Coastal Research 2006(223), 581-586, (1 May 2006). https://doi.org/10.2112/04A-0001.1
Received: 6 May 2004; Accepted: 6 May 2004; Published: 1 May 2006
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