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Previous assessments of thermally transferred optically stimulated luminescence (TT-OSL) signal resetting in natural sedimentary settings have been based on relatively limited numbers of observations, and have been conducted primarily at the multi-grain scale of equivalent dose (D e) analysis. In this study, we undertake a series of single-grain TT-OSL bleaching assessments on nineteen modern and geological dating samples from different sedimentary environments. Daylight bleaching experiments performed over several weeks confirm that singlegrain TT-OSL signals are optically reset at relatively slow, and potentially variable, rates. Single-grain TT-OSL residual doses range between 0 and 24 Gy for thirteen modern samples, with > 50% of these samples yielding weighted mean D e values of 0 Gy at 2σ. Single-grain OSL and TT-OSL dating comparisons performed on wellbleached and heterogeneously bleached late Pleistocene samples from Kangaroo Island, South Australia, yield consistent replicate age estimates. Our results reveal that (i) single-grain TT-OSL residuals can potentially be reduced down to insignificant levels when compared with the natural dose range of interest for most TT-OSL dating applications; (ii) the slow bleaching properties of TT-OSL signals may not necessarily limit their dating applicability to certain depositional environments; and (iii) non-trivial differences may be observed between single-grain and multi-grain TT-OSL bleaching residuals in some modern samples. Collectively, these findings suggest that single-grain TT-OSL dating may offer advantages over multi-grain TT-OSL dating in certain complex depositional environments.

Abstractthe vertebrate fossil deposits of the naracoorte Caves in south eastern South Australia preserve a long-term record of local faunas. We provide here an updated list of small mammal faunas of late Quaternary (c. <50 ka) aged fossil assemblages from Wet, Robertson and blanche Caves as a basis for understanding past and future patterns in species occurrence. the updated list includes seven species previously unrecorded from the <50 ka period from this region. Of these, two species (Dasycercus sp. indet. and Pseudomys novaehollandiae) are new to the naracoorte fossil record and have no known regional historical (european colonisation to 1950) or contemporary (post 1950) distribution. Review of fossil collections such as these is crucial for providing up-to-date species occurrence data which can be used to establish baselines of past species diversity and information about the past geographic ranges of individual taxa through time.

We examined mammal occurrence and variability through the Late Pleistocene vertebrate fossil deposit of Grant Hall in Victoria Fossil Cave, Naracoorte, South Australia. To determine long‐term patterns of change, we compared the composition and relative abundance trends of the assemblage with a nearby Middle Pleistocene deposit in Cathedral Cave. Total species richness did not change through the Grant Hall sequence, dated from 93 ± 8 to 70 ± 5 ka. However, species relative abundances varied between ecologically divergent species, and in some cases between species that demonstrate similar environmental preferences. For some species this variation is comparable to that recorded in Cathedral Cave. Of those showing similar trends between the two deposits, the forest inhabitant, Pseudomys fumeus, recorded an 8.6% decline through Grant Hall, coincident with a 9.7% increase in the dry heath/mallee dweller Pseudomys apodemoides. These patterns indicate that climatic transition from relatively warm, moist to cooler, drier conditions impacted some species in similar ways through climatic cycles of the past. However, the majority of the fauna demonstrated complex responses that are individual and variable through time. Statistical tests of species trends from the Grant Hall assemblage caution that large fossil samples are required to validate patterns observed. Copyright © 2012 John Wiley & Sons, Ltd.