Evidence for holocene sea level change at Verlorenvlei, Western Cape, South Africa

A series of sediment cores extracted from what is today a large freshwater coastal lake, Verlorenvlei, has been sub-sampled, radiocarbon-dated and subjected to a range of palaeoenvironmental techniques, in particular pollen analysis, sedimentology and geochemistry. A mid-late-Holocene higher sea level is evident in the cotes indicating the rapidity with which sea level change can occur and invoke other forms of environmental response. Following a hiatus in sedimentation, most probably around 3800 BP, the marine conditions at the site were replaced by fresh water as the dominant hydrological and ecological influence. Laminated organic sediments in some of the cores suggest that, around 300 years ago, a fresh water lake characterised Verlorenvlei. Since then, the picture revealed by high-resolution palynology is one of progressive levels of human disturbance both in and around the study area. Sedimentological and palaeoecological analyses of additional cores from the vlei, two from the distal (inland) and one from the proximal (coastal) end of the system, serve further to elucidate the precise nature of sea level change in the late Holocene and facilitate the construction of a refined Holocene sea level curve for the region. Environmental changes in the late Holocene are shown to be especially dynamic. (C) 1999 INQUA/Elsevier Science Ltd. All rights reserved.