LATE HOLOCENE ENVIRONMENTS AT VERLORENVLEI, WESTERN CAPE PROVINCE, SOUTH-AFRICA

Evidence on late Quaternary palaeoenvironments of the western and sout hwestern Cape of South Africa has facilitated detailed reconstructions mainly for the mountains, where organic sediment accumulation has bee n favoured by relatively humid climates. On the lowlands, particularly those of the west coast region, the search for sites traditionally re garded as suitable for the accumulation of sediments containing preser ved fossil pollen has commenced only more recently. This area of the W estern Cape Province has, however, provided Quaternary scientists with a rich archaeological record that has yet to be tested against indepe ndent lines of palaeoecological evidence. A sequence of sediments whic h have accumulated in what is today a large freshwater coastal lake, V erlorenvlei, has been sampled at Grootdrift, 15 km inland of the coast . A series of seven sediment cores was extracted during 1991 and three of these have now been sub-sampled, radiocarbon dated and subjected t o a range of palaeoenvironmental techniques, in particular pollen anal ysis, sedimentology and geochemistry. Three pollen diagrams are presen ted which reveal the vegetation history of both the immediate Grootdri ft environment and the wider catchment during several periods over the last 5500 years. A mid-Holocene higher sea-level is evident in two of the cores which were examined for pollen throughout their length. The surrounding area appears at this time to have been somewhat more arid than today. Following a hiatus in sedimentation some time after 4300 BP, the marine conditions at the site disappear and are replaced by fr esh water as the dominant hydrological and ecological influence. Aroun d the time of colonial occupation of the region, some 300 years ago, l acustrine conditions prevailed at Grootdrift and greater moisture avai lability is indicated in the catchment. During the last 300 years, the picture revealed by high resolution palynology of the third core is o ne of progressive levels of human disturbance both in and around the V erlorenvlei. Evidence from a textural and geochemical analysis of the sediments is consistent with the interpretation based on fossil pollen . The implications of this information are examined against the archae ology and palaeoecology of several cave sites in the vicinity of the v lei. The consistency apparent in the range of types of evidence sugges ts that some reliance can be placed on the mid-late Holocence palaeoen vironmental reconstruction at Verlorenvlei. The paper thus provides in sight into the nature of the complex interactions between late Holocen e climate change, sea-level fluctuation, vegetation change, vlei hydro logy and human activity in the Western Cape coastal region. Copyright (C) 1996 INQUA/Elsevier Science Ltd