Palaeoenvironmental developments in the Lake Tondano area (N. Sulawesi, Indonesia) since 33,000yr B.P.

Copyright © 2001 Elsevier Science B.V. All rights reserved.Geo(morpho)logical, sedimentological and ecological developments in the Lake Tondano area since ±33,000 yr B.P., and limnological changes in the moderately-sized lake situated at 680 m asl in the northern part of Sulawesi, Indonesia are discussed. First, the environmental setting of the lake is presented. Study of the regional distribution of lacustrine sediments, and a detailed analysis of their sedimentary facies (texture, organic matter content) suggest major changes in size and depth of the lake and in past sedimentation. Insight into the long-term development of the lake (sedimentation processes) is highly relevant for sustainable use of the present lake. Analysis of diatom assemblages provides further detail of the changing aquatic settings of the lake; lake levels rise quickly around 33,000 and 12,000 yr B.P., fall dramatically between ±30,000 and 13,000 yr B.P. and are lowered gradually since approximately 6000 yr B.P., following Early Holocene high lake levels. Drainage of the lake is affected by both volcanic depositional events and regional climatic events. Palynological analysis is indicative of local palaeoecological settings in the lake area and regional climatic change; a distinct, Late Pleistocene phase, with lower precipitation and lowered mean temperatures is inferred. Furthermore, progressive deforestation of the Tondano uplands is evident, as well as diffuse anthropogenic/volcanic vegetation disturbance from the early Mid Holocene onwards. Information from sedimentary facies, diatom assemblages and local palaeoecology (pollen) are integrated to reconstruct palaeoenvironmental settings and processes in the lake area. This record of environmental change as well as the pollen-based record of regional vegetation and climate change corroborates other palaeoenvironmental data derived from the few terrestrial sites in the region. The data attribute a greater magnitude of temperature and precipitation change in the region than is commonly deduced in studies based on marine faunal and sedimentary records. The Lake Tondano sedimentary record is highly suitable for further analysis aimed at determining the exact timing and amplitudes of environmental change in the SE Asian equatorial region.Rien A. C. Dam, Jennie Fluin, Papay Suparan and Sander van der Kaarshttp://www.elsevier.com/wps/find/journaldescription.cws_home/503355/description#descriptio

Late Quaternary palaeoecology, palynology and palaeolimnology of a tropical lowland swamp: Rawa Danau, West-Java, Indonesia

Copyright © 2001 Elsevier Science B.V. All rights reserved.Sedimentological, limnological and palynological analyses of a sediment core from a lowland site in West-Java, Indonesia, provide a detailed palaeoenvironmental record for the Late Glacial and the Holocene. The record suggests open vegetation under inferred drier climatic conditions for the Late Glacial. However, there is no unequivocal evidence for cooler conditions at this time. The onset of the Holocene coincides with a change to more humid climatic conditions, with the development of a fern-rich closed forest vegetation type. Dramatic changes in diatom community composition provide a striking record of habitat change associated with lake shallowing, but this process appears to be a result of basin in-filling rather than variations in precipitation/evaporation balance associated with climatic fluctuations. Evidence for human impact on the vegetation development is restricted to the last few hundred years.Sander van der Kaars, Dan Penny, John Tibby, Jennie Fluin, Rien A. C. Dam and Papay Suparanhttp://www.elsevier.com/wps/find/journaldescription.cws_home/503355/description#descriptio