Radiocarbon dating of mangrove sediments to constrain Holocene relative sea-level change on Zanzibar in the southwest Indian Ocean

Abstract

Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. We cannot determine whether there was a RSL highstand above present on Zanzibar during the mid 2 to lateHolocene. The RSL reconstruction agrees broadly with changes predicted by the ICE-5G geophysical model, which includes 4 m of ice equivalent sea-level rise between 7000 and 4000 cal.yr BP. Our new dating approach has the potential to provide improved chronologies with which to interpret sea level data from this and other mangrove environments.

Late Holocene Palynological Record and Landscape Change From the Piraquê-Açu and Piraquê-Mirim Estuarine System, Espírito Santo, Brazil

“…In fact, the records of both cores display a coherent signal and were not apparently affected by bioturbation. This is indeed similar to what was also observed by Woodroffe et al (2015) in analysed sediments from southeast India. The pollen record of the cores (PA20 and PM1) demonstrated significant differences in the water circulation behaviour of each river that forms PAPMES.…”

“…Similar observations also were observed in other regions such as in Venezuela (Muller, 1959) and India (Woodroffe et al, 2015). The analysed sediments in the mangroves influence areas in the southeastern region of Brazil and have been found at low frequencies (Belem, 1985;Coelho et al, 1999, Amaral et al, 2006.…”

“…This effect also was not observed and in the sediment cores from mangrove area in Zanzibar (Woodroffe et al, 2015). In fact, the records of both cores display a coherent signal and were not apparently affected by bioturbation.…”

“…Areas that are dominated by mangroves favour the organisms' establishment that can cause bioturbation in the sediment (Woodroffe et al, 2015). Likewise, mangrove roots may penetrate up to 2 m into underlying sediments generating youngest sediments remobilization to oldest (Hutchings and Saenger, 1987).…”

Holocene Relative Sea-Level Changes from Near-, Intermediate-, and Far-Field Locations

“…Part of these uncertainties results from the large distances between field sites (e.g., South Africa to Mozambique) and the varied RSL reconstruction methods used [145]. At sites on the mainland of southeast Africa, RSL reached~2.5 to 3.5 m above present by 6 ka [144].…”