Fluvial response to late Quaternary climate change in NE Queensland, Australia Michael F. Thomas a, ⁎ , Jonathan Nott b , Andrew S. Murray c , David M. Price d a School of Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, UK b School of Tropical Environment Studies and geography, James Cook University of North Queensland, Cairns, Qld 4870, Australia c Nordic Laboratory for Luminescence Dating, Aarhus University, Roskilde, Denmark d School of Geosciences, University of Wollongong, NSW 2522, Australia Accepted 27 February 2007 Abstract Samples of alluvial and colluvial deposits from the coastal plain and coastal valleys north and south of Cairns (17°S) have been dated using optically stimulated luminescence (OSL) protocols, with additional thermoluminescence (TL) and Radiocarbon assays. Coarse fanglomerates from elevated coastal terraces date back to 81 ka, but most are clustered in oxygen isotope stage three (OIS3, 64–28 ka), indicating high-energy conditions during this period. Extensive fans and terraces of finer calibre sediments are widely represented grading from coarse gravels and cobbles in proximal zones fine sand and silt in distal areas. Dates show that vertical accumulation of 10–15 m of sediment occurred between ∼ 28 and 14 ka (OIS2), after which the fans were dissected and Holocene deposits become fragmentary. A number of deposits indicating hillslope instability were successfully dated and these fall mainly into OIS3 and post 12 ka. These results are interpreted as catchment responses to Late Pleistocene climate and vegetation changes, documented elsewhere from local pollen and ocean drilling sites. Correlation with these records and with evidence for regional climate change from the Austral-Asian region is good and indicates that these changes were sufficient to transform fluvial activity and slope processes. © 2007 Elsevier B.V. All rights reserved. Keywords: Late Quaternary environments; Humid tropics; Debris flows; Alluvial fans; Queensland geomorphology 1. Introduction The study area extends along 100–150 km of coastal plain North and South of Cairns in northeast Queensland and includes the catchments draining the Eastern Highlands (Great Dividing Range) towards the Coral Sea (Figs. 1 and 2). The region belongs to the seasonally humid tropics and rainfall is 3000 mm y− 1 at lower elevations but rises to over 8000 mm y− 1 near the sum- mit of Bellenden Ker. The rainfall is sufficient to support tropical rainforest, which still clothes the landscape in steep, remote or protected areas, which include the ‘The Wet Tropics’ World Heritage Area. The area exhibits steep environmental gradients today, with areas of trop- ical rainforest giving way inland to (eucalypt) scler- ophyll woodland over short distances. A programme of TL and OSL dating based on sedi- ments deposited from the east-flowing rivers was carried out to establish the behaviour of stream catchments during the Last Glacial Cycle (LGC). Previous reports Palaeogeography, Palaeoclimatology, Palaeoecology 251 (2007) 119 – 136 www.elsevier.com/locate/palaeo ⁎ Corresponding author. Tel.: +44 1786467840; fax: +44 1786467843. E-mail address: m.f.thomas@stir.ac.uk (M.F. Thomas). 0031-0182/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.palaeo.2007.02.021