Late Quaternary palaeolimnology of a tropical marl lake: Wallywash Great Pond, Jamaica

摘要: Wallywash Great Pond (17° 57′ N, 77° 48 W, 7 m a.s.l.) is the largest perennial lake in Jamaica. It occupies a fault trough within karstic White Limestone. The hardwater with pH of 8.2–8.6 and an alkalinity 3.6–3.9 meq 1−1. Its chemistry strongly influenced by spring discharge from limestone. water subject to degassing, evaporation bicarbonate assimilation submerged plants algae, resulting marl precipitation. A 9.23 core (WGP2), taken depth 2.8 m, was analysed for magnetic susceptibility, loss-on-ignition, carbonate content, mole % MgCO3 calcite, stable isotopes fine fraction. chronology based on ten14C four U/Th dates. Four main sediment types alternate core: marl; organic, calcareous mud; organic mud or peat; earthy, brown, mud. marls represent periods wet/warm climate during sea-level highstands deposits, shallower, swampy conditions. In contrast, muds were laid down when dry ephemeral. last interglacial (120 000- 》 106 000 yr BP) represented three distinct units. After interval, stable, conditions set 93 BP. dry/cool prevailed between at least 9500 Three subsequent cycles alternating wet culminated flooding basin Black River late Holocene. These recent events cannot be accurately dated by14C due significant temporally-variable inputs ‘dead’ carbon springs.