A record of fire, vegetation and climate through the last three glacial cycles from Lombok Ridge core G6-4, eastern Indian Ocean, Indonesia

Charcoal, elemental carbon and elastic particle analyses have been undertaken on tropical marine core G6-4 collected from the eastern Indian Ocean between the Lesser Sunda Islands of Indonesia and northwestern Australia to help interpret an existing pollen record. In addition, a new oxygen isotope record has been constructed, and several radiocarbon dates produced, to allow a refinement of the chronology of the core. The record covers the last 300,000 years with three clear glacial-interglacial cycles. However, the new oxygen isotope record and radiocarbon dates suggest a hiatus and it appears that most isotope stage 3 is missing. Interglacials are characterised by higher values of mangrove, fern and rainforest pollen indicating wetter conditions than intervening glacials which have higher Cyperaceae and Chenopodiaceae values. Gramineae percentages are also generally higher during glacials but there is a sustained increase in grasses relative to Eucalyptus about 185,000 years ago originally interpreted as a change to drier conditions. An increase in burning from about 200,000 years ago from charcoal evidence suggests that fire may have been an important contributing factor. This and subsequent increases in charcoal may reflect anthropogenic burning and are considered in relation to archaeological evidence for possible times of arrival of people within Australia. The elemental carbon record shows major differences to that from charcoal and further research is needed to interpret its meaning. Little consistent evidence for changes in climate or vegetation disturbance is provided by elastic particle influx which may well reveal a record of volcanicity within the region. (C) 1999 Elsevier Science B.V. All rights reserved.