Late Pleistocene and Holocene landscape evolution and environmental change in the Lake Sulivan area, Falkland Islands, South Atlantic

摘要

Late Pleistocene and Holocene landscape evolution around Lake Sulivan, Falkland Islands, South Atlantic, is assessed using morphological, stratigraphical, paleoecological and C-14-dating evidence. Data indicate a complex landscape history involving frost-related activity, ventifact development, growth and degradation of peat terrain, expansion and contraction of lakes, and the development, stabilisation and subsequent reworking of alluvial and aeolian sand bodies. Late Pleistocene cold conditions favoured production of sandy diamicts on hillslopes, and ventifacts on outcrops and blockfield clasts. Lateglacial climatic amelioration was marked by early growth of peat (ca 16,500 cal. yr BP). Since then, peat accumulation, changes in lake areas and depths, and alluvial and/or aeolian sand deposition have been recurring and dominant features of landscape change which throughout the Late Pleistocene and early Holocene may have been a response to near-synchronous climatic fluctuations along the South America Antarctica axis. Marked landscape changes around Lake Sulivan coincided with intervals of glacier readvance in South America and South Georgia at ca 3200-1900 and 700-100 cal. yr BP: with lower lake levels and aeolian sand transport from exposed lakebeds and shorelines implying greater aridity in the Falklands than at present. (C) 2002 Elsevier Science Ltd. All rights reserved. [References: 64]