Reliability of mangrove radiocarbon chronologies: A case study from Mahé, Seychelles

Mangrove sediments are valuable archives of paleoenvironmental and relative sea-level changes. The most widely applied method to obtaining chronologies past changes in mangrove is radiocarbon dating, because mangroves produce large amounts organic matter situ. However, there many challenges reliable bioturbation processes from roots crabs can rework sediments, resulting ages that not stratigraphic order. Previous studies have suggested methods isolate specific sediment size fractions may yield closer the age paleo depositional surface by removing younger carbon contamination fine roots. This study examines which sample types more likely using shallow cores a environment on Mahé, Seychelles, Indian Ocean. We compare bulk sediment, sieved concentrates above-ground macrofossils collected same depths. Bulk concentrate comparable, suggests separate out different do sources Seychelles cores. Identifiable rare cores, but older than comparable or ages. suggest limited accommodation space over late-Holocene, determined relatively stable sea levels, has resulted poor preservation for dating due low rates burial accretion. Low accretion sequence highly bioturbated degraded, meaning both samples impacted argue availability composition controls reliability chronologies, implications choice site selection.