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This is the authors’ version of an article published in Quaternary Science Reviews. The published version is available by subscription at: http://www.journals.elsevier.com/quaternary-science-reviews/

Please cite this as: Macken, A.C., Jankowski, N.R., Price, G.J., Bestland, E.A., Reed, E.H., Prideaux, G.J. and Roberts, R.G., 2011. Application of sedimentary and chronological analyses to refine the depositional context of a Late Pleistocene vertebrate deposit, Naracoorte, South Australia. Quaternary Science Reviews, 30, 2690-2702. doi:10.1016/j.quascirev.2011.05.023

Please note that any alterations made during the publishing process may not appear in this version.

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Application of sedimentary and chronological analyses to refine the depositional context of a Late Pleistocene vertebrate deposit, Naracoorte, South Australia

Amy C. Mackena,*, Nathan R. Jankowskib, Gilbert J. Pricec, Erick A. Bestlandd, Elizabeth H. Reeda,e, Gavin J. Prideauxa, and Richard G. Robertsb a School of Biological Sciences, Flinders University of South Australia, Bedford Park, SA 5042, Australia b Centre for Archaeological Science, School of Earth and Environmental Sciences, The University of Wollongong, Wollongong, NSW 2522, Australia c School of Earth Sciences, The University of Queensland, St Lucia, Qld 4072, Australia d School of the Environment, Flinders University of South Australia, Bedford Park, SA 5042, Australia e Department for Environment and Natural Resources, PO Box 134, Naracoorte, SA, 5271, Australia

*Corresponding Author Ph. (08) 8201 2630 / fax (08) 8201 3015 [email protected]

Abstract Cave deposits of infill sediments and associated vertebrate fossils provide a valuable source of information on terrestrial palaeoenvironments, climatic conditions and palaeocommunities. In the deposits of the Naracoorte Caves World Heritage Area, such records span the last 500 ka and are renowned for their rich, diverse vertebrate assemblages. Previous research into the Grant Hall deposit of Victoria Fossil Cave suggested that it may preserve the only peak last interglacial (ca. 125 ka) faunal community within the World Heritage Area. The current work tested this existing model for the age of faunal remains from Grant Hall using multiple techniques. Physical and geochemical properties of the visually homogeneous sediments were analysed at regular intervals through the sequence to establish meaningful stratigraphic divisions and sediment provenance. Optically stimulated luminescence dating of individual quartz grains indicates that sediments accumulated in Grant Hall from 93 ± 8 to 70 ± 5 ka. Minimum ages provided by U/Th dating of fossil teeth (72.3 ± 2.2 to 38.2 ± 0.8 ka) are consistent with the luminescence chronology, and show that the deposit represents a more recent faunal accumulation than previously modelled for the site. U/Th ages on calcite straws within the deposit are significantly older than the sediments and fossil teeth (>500 to 186.4 ± 1 ka). As such they provide no further constraint on the chronology of the deposit but do indicate that speleothem deposition was active over much of the Middle Pleistocene. Sedimentary analyses resulted in the identification of five depositional units, contrasting with previous divisions which were based only on visual observation of the sedimentary sequence. Sediments within each unit are broadly classified as sandy silts with soil structures and may be indirectly derived from the lunettes of nearby Bool Lagoon, although their ultimate provenance is unknown. As a result of this work, palaeoenvironmental reconstruction based on fossil remains in the deposit may be more accurately related to prevailing climatic and environmental conditions at the time of accumulation. It also contributes to an understanding of the temporal occurrence of regional vertebrate faunas through the Late Pleistocene, reinforcing the value of developing stratigraphically constrained chronologies for cave deposits based on multiple techniques.

Keywords Late Pleistocene; optically stimulated luminescence dating; U/Th dating; Naracoorte Caves; cave sediments

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1. Introduction

The vertebrate fossil deposits of the Naracoorte Caves World Heritage Area (NCWHA) in south eastern South Australia contain a palaeoenvironmental record from the Middle Pleistocene to the present (Wells et al., 1984; Reed and Bourne, 2000; Prideaux et al., 2007). Examination of fossil assemblages from these deposits has provided insights into the impacts of past aridity and climatic warming on local faunal communities and may be useful when making assessments of the potential impacts of future climate change on biodiversity (Prideaux et al., 2007; Macken, 2009). Analyses of cave sediments, speleothem growth patterns and other palaeoecological proxies such as stable isotopes and pollen is an important component of such assessments. They provide the chronological, accumulation and palaeoenvironmental context of cave deposits and have been important for palaeoecological interpretations of the NCWHA fossil record (e.g., Ayliffe et al., 1998; Demarshelier et al., 2000; Forbes and Bestland, 2007; Forbes et al., 2007; Darrénougué et al., 2009) and cave deposits elsewhere (e.g., Denniston et al., 1999; Hearty et al., 2004; Bacon et al., 2008).

The fossil deposit of Grant Hall, a chamber within Victoria Fossil Cave (VFC; 5U1) is the only known deposit to sample the last interglacial period from the NCWHA and may be significant in terms of past environmental records for the region (Moriarty et al., 2000; Grün et al., 2001; Fraser and Wells, 2006). Its age is constrained by U/Th dates on underlying and capping flowstone layers to ca. 206 and 76 ka (Ayliffe and Veeh, 1988), although Moriarty et al. (2000) suggested that deposition occurred over a short interval of only 10 thousand years across the peak of the last interglacial (130 to 120 ka). This model was based on the visual homogeneity of the sediments and electron spin resonance ages for the fossil assemblage obtained from tooth enamel (Grün et al., 2001). In contrast, a single optically stimulated luminescence (OSL) age of 84 ± 8 ka for the site suggests that accumulation continued, at least in part, through the later stages of MIS-5 (Roberts et al., 2001).

The faunal assemblage is taxonomically diverse, containing a minimum of 47 species including the remains of a broad range of extinct and extant mammals, reptiles and birds (Fraser and Wells, 2006). A unique feature of the assemblage is the low proportion of grazing versus browsing macropodids (kangaroos and wallabies) when compared to other NCWHA deposits (Reed, 2003; Fraser and Wells, 2006; Prideaux et al., 2007). This apparent change in the structure of the regional faunal community may represent a response to climatic conditions associated with the peak of the last interglacial (Fraser and Wells, 2006). As identified by Fraser and Wells (2006), resolving the extent to which the deposit represents a unique fauna associated with the last interglacial requires both (a) systematic sedimentary analysis and dating through the depositional sequence, and (b) further excavation of the deposit to increase the fossil sample to better discern ecological trends. Given the paucity of stratigraphically and chronologically refined Pleistocene fossil deposits in Australia, continued study of cave deposits such as Grant Hall is required to advance understanding of climate impacts on Quaternary faunas, and to resolve the causes and timing of the Late Pleistocene extinctions (Prideaux, 2006; Price et al., 2011).

This paper presents the results of a detailed, high-resolution chronological and sedimentary analysis of the Grant Hall deposit in order to provide a more finely resolved context for interpreting the fossil faunas. We aimed to (a) determine the age profile of the site using OSL dating of quartz grains, and U/Th dating of fossil teeth and fallen calcite straws incorporated into sediments to test the model of rapid accumulation over the peak of the last interglacial, and (b) profile the character of sediments within the deposit, their potential sources and stratigraphic division based on systematic analysis of sediment colour, grain size and shape and geochemistry.

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2. Location and Geological Setting of the Naracoorte Caves

The NCWHA is located in the Upper South East region of South Australia, 12 km south east of Naracoorte (Fig. 1). The caves are located in the Naracoorte member of the Oligocene–Miocene Gambier Limestone, a fossiliferous carbonate formation of marine origins (Ludbrook, 1961). Phreatic dissolution of this limestone and structural processes associated with movement of the Kanawinka fault contributed to cave development (Wells et al., 1984; White, 2005). Dating of clastic sediments, bone material and speleothems indicates that the Naracoorte caves first opened to the surface during the Early to Middle Pleistocene (Ayliffe and Veeh, 1988; Ayliffe et al., 1998; Grün et al., 2001; Prideaux et al., 2007).

Overlying the Gambier limestone is a sequence of 13 sub-parallel stranded Pleistocene beach dune facies, distributed across south eastern South Australia from Naracoorte to the coast at Robe (Sprigg, 1952; Murray-Wallace et al., 2001). These ridges are composed of bioclastic, calcareous carbonates of the Bridgewater formation (Belperio, 1995). The NCWHA cave system underlies the easternmost of these dunes, the Naracoorte East Ridge which may be as old as 935 ± 178 ka (Murray-Wallace et al., 2001).

For reference purposes, cave identification numbers (e.g., 5U1) are provided in text and follow the Australian Speleological Federation Cave and Karst Numbering Code (Matthews, 1985) and Reed and Bourne (2000). “5” indicates the state of South Australia and “U” the upper south east region of South Australia.

3. Methods

3.1 Site Selection and Excavation

Previous palaeoecological and taphonomic study of the Grant Hall fossil deposit was based on material excavated from four 1x1m grid squares, G1, 2, 5 and 6 (Gresham, 2000; Fraser and Wells, 2006; Fig. 1). The excavated portions of these grid squares vary in depth from 40 to 90 cm due to the presence of an undulating flowstone layer underlying the fossiliferous sediment. The current study involved a systematic excavation of grid square 7 (G7). This grid was selected to increase the cross sectional view of the sediment fan and capture a depth of at least 90 cm, inferred from the shape of the flowstone floor.

Original assessment of the deposit identified three stratigraphic units based largely on the presence of two narrow bands (sublayers) that divide the profile (Fraser and Wells, 2006), contrasting with six sedimentary layers and three sublayers identified in a pilot investigation of the sequence conducted prior to our study (Macken, 2009; Fig. 2). Based on this pilot assessment, G7 was excavated in 5 cm intervals defined within each of the six stratigraphic layers (A to F; Fig. 2). These were measured with a laser finder and dumpy level with respect to the primary datum (Fig 1). Excavation layers are referred to in text by their depth below the primary datum (D/D) as indicated by the scale bar of Fig. 2.

3.2 Optically Stimulated Luminescence Dating

Paired OSL and dosimetry samples were collected from each of the sedimentary layers (A to F), with an additional sample collected from Layer E directly adjacent to an articulated partial macropodid pes and tibia (Fig. 2). Prior to collection, the exposed face was cleaned to avoid sampling of grains exposed to white-light. Samples were collected under red-light conditions by

3 Archived at Flinders University: dspace.flinders.edu.au hammering opaque plastic tubing, 20 cm long by 5 cm diameter, into the exposed sedimentary walls of G7 at the depths indicated in Figure 2.

Sample preparation and analysis was conducted in the Centre for Archaeological Science at the University of Wollongong. Quartz grains of 180–212 μm in diameter were extracted from each sample following the standard pre-treatment methods and procedures described by Aitken (1998). Quartz grains were etched in 45% hydrofluoric acid for 40 min to remove the alpha-irradiated rinds and any residual feldspar grains.

Equivalent dose (De) values for individual quartz grains were determined using the single-aliquot regenerative-dose protocol as detailed in Table A.1 (Appendix A) and following Murray and Roberts (1998), Galbraith et al. (1999) and Murray and Wintle (2000). Preheat conditions were validated by the results of a dose recovery test on 106 grains from a sun-bleached subsample of GH09-4. This produced a ratio of measured to given dose of 0.98 ± 0.02, with an overdispersion value of 14.6 ± 1.7%, where overdispersion is a measure of the spread in De values remaining after all measurement uncertainties have been taken into account (Galbraith et al., 1999; Jacobs and Roberts, 2007).

All luminescence measurements were carried out on an automated Risø TL/OSL reader fitted with a green laser attachment for stimulation of individual grains. Calibrations and procedures for irradiations and grain stimulation are described in Appendix A. Following stimulation, the data associated with each grain were subjected to objective quality-assurance criteria (Table A.2 Appendix A), based on those of Jacobs et al. (2006a).

The De for grains that satisfied the quality-assurance criteria was estimated by fitting a dose- response curve through the sensitivity-corrected regenerative-dose OSL points, using either a single exponential function or one incorporating a linear term. Application of the latter function is common in OSL dating studies (e.g., Aitken, 1998; Jacobs et al., 2003, 2006b; Turney et al., 2008) and was used where necessary to provide a better fit through the regenerative dose points. The sensitivity-corrected natural OSL signal was then projected onto the fitted dose-response curve to obtain the De. The De values, and their associated uncertainties (determined by Monte Carlo simulation, including an uncertainty of 2% per OSL measurement to reflect instrumental irreproducibility; Jacobs et al., 2006b), were then displayed on radial plots (Fig. A.2 Appendix A) to assist with the interpretation of the De distributions and the choice of appropriate age models.

The total dose rate for acid-etched quartz grains is derived mainly from the beta and gamma radiation from the surrounding sediment, with minor contributions from cosmic-rays and internal alpha radiation. The gamma and beta dose rates were measured using a combination of thick- source alpha counting and beta counting for sample GH09-1 and by in situ gamma-ray spectrometry and beta counting for all other samples (Appendix A). The cosmic-ray dose rates were estimated using the equations of Prescott and Hutton (1994) with allowances for site specific factors as detailed in Appendix A. Estimation of internal alpha dose rates is also described in Appendix A.

3.3 U/Th Dating of Fossil Tooth Dentine and Calcite Straws

Fossil teeth and calcite straws were U/Th dated using a thermal ionisation mass spectrometer (TIMS) and multi-collector inductively-coupled plasma mass spectrometer (MC-ICP-MS), respectively, at the Radiogenic Isotope Facility, The University of Queensland. Six fossil teeth were selected from layers A, B, C and D (Fig. 2) and included specimens that were well- preserved, unabraded and thus, were unlikely to have been subjected to reworking from older

4 Archived at Flinders University: dspace.flinders.edu.au deposits. Twelve well-preserved straw stalactites were selected from layers B, C, D and F (Fig. 2).

Direct U/Th dating of tooth dentine is based on the premise that U and Th are negligible in living tissues. In fossil teeth, U is taken up after burial from meteoric groundwater, whilst Th is excluded (Pike et al., 2002). Thus, the age is determined by calculating the amount of 230Th that is produced by the radioactive decay of 238U (via a series of intermediate isotopes). In most cases, the resulting age will be a minimum age only, provided that U has not been lost from the system after initial uptake (Grün et al., 2000; Pike et al., 2002). In contrast, speleothems such as straw stalactites are closed systems for U. That is, the U is fixed within the speleothem calcite (or aragonite) during genesis. Thus, U/Th dating of speleothem will provide the true age of initial calcite crystallisation (Zhao et al., 2001; Prideaux et al., 2010). All teeth and straw stalactite samples were pre-treated and dated following techniques described in Zhao et al. (2001), Yu et al. (2006), Price et al. (2009) and St Pierre et al. (2009). All U/Th dates are reported to 2σ error.

3.4 Sediment Analysis

3.4.1 Physical properties In order to determine the physical properties of the Grant Hall sediments, colour, grain roundness and grain size were measured for 12 sediment samples distributed systematically through the sequence (indicated in Fig. 2). All analyses were conducted in the School of Biological Sciences and the School of the Environment at Flinders University, South Australia. Sediment samples from layers D/D 52–58 cm, 88–90 cm and 121–130 cm were prepared as thin sections by Pontifex and Associates in Kent Town, Adelaide.

Sediment colour was determined from air dried sediment using a Munsell Soil Colour Chart under natural light conditions. Grain roundness was determined by visual comparison with Powers Roundness Scale (Powers, 1953). To reduce confounding in the measurement of roundness due to differential abrasion between grain types, only quartz grains were analysed. Using a fine brush, quartz grains were isolated from 20 g sediment samples for visual observation under a Leica MS 5 dissecting microscope. Fifty individual grains were classified according to Powers Roundness Scale. Average roundness for the sample was calculated following Powers (1953).

Grain size was measured with a Malvern Mastersizer 2000 Laser Particle Sizer on 100°C oven dried sediment samples. Samples were sieved to separate the >2000 μm, 1000–2000 μm and <1000 μm sized fractions. Each fraction was weighed independently to determine the relative contribution of these fractions to the sediment and to determine bulk grain size distributions by % weight. Only the <1000 μm fraction was measured by the Particle Sizer in accordance with manufacturer’s recommendations. Using this technique, grain size distributions based on volume are determined from the obscuration of light by grains suspended in solution. At an obscuration value between 7 and 10%, five measurements of grain size distribution were made and an average value from these was calculated by the Particle Sizer. Grain size statistics were calculated using graphic methods from grain size cumulative % frequency curves for the <2000 μm fraction, following Boggs (1995).

3.4.2 Major and trace elemental geochemistry Geochemical profiling was conducted to enable differences in sediment character to be detected through the sequence, and for tracing the potential provenance of the sediments to regional surface deposits. Bulk sediment geochemistry for each of the 12 sediment samples was conducted

5 Archived at Flinders University: dspace.flinders.edu.au by Acme Analytical Laboratories, Vancouver, Canada using whole rock Inductively Coupled Plasma light emission spectrometry providing: (i) Weight % contribution of major elemental oxides (Al2O3, Fe2O3, CaO, MgO, Na2O, K2O, MnO, TiO2, P2O5, Cr2O3), (ii) Concentration of minor elements (Ba, Co, Cu, Nb, Ni, Sc, Sr, Y, Zn, Zr and Ce) in parts per million (ppm) and, (iii) Weight % contribution of total carbon and sulphur using the Leco high-frequency induction furnace technique.

Samples used for this analysis were prepared in the School of the Environment, Flinders University. Preparation involved drying the <2000 μm fraction which was then ground to a fine powder. Removal of the >2000 μm fraction ensured that limestone and bone fragments were not incorporated in the sample. Linear regression was applied to the geochemical data to assess the nature and extent of major and trace elemental trends within the Grant Hall sediments.

3.4.3 Comparison with Naracoorte cave infill sediments and surface deposits The grain size distribution of Grant Hall sediment samples was compared to cave fills from Fossil Chamber, Victoria Fossil Cave (Reed, 2003), Robertson Cave (5U17, 18, 19), Wet Cave (5U10, 11) and Starburst Chamber, Victoria Fossil Cave (Forbes and Bestland, 2007) using graphic cumulative volume % plots. These plots are based on the frequency of grains in the following size classes: >500 μm (coarse sand and greater), 500–300 μm (medium sand), 300–100 μm (fine to very fine sand) and <100 μm (very fine sand to silt). Major and trace elemental values of Grant Hall sediment samples were plotted with those of regional surface sediments and other Naracoorte cave fills as detailed in Forbes and Bestland (2007) as well as local Terra Rossa Soils after Mee et al. (2004).

4. Results

4.1 OSL Chronology

OSL age estimates are presented in Table 1 and indicate that accumulation of quartz-bearing sediments in the Grant Hall deposit occurred in the Late Pleistocene. The lowermost sample (GH09-6) has an OSL age of 93 ± 8 ka (D/D 136–141 cm) with the youngest ages of 70 ± 5 ka and 70 ± 6 ka measured from D/D 52–58 cm and D/D 61–66 cm (samples GH09-7 and GH09-2). De values and distributions are presented in Table A.3 and Figure A.2 of Appendix A. These suggest that the Grant Hall samples contain populations of grains that were not all bleached to the same extent at the time of deposition on the cave floor. Under these circumstances, the most fully bleached grains are those with the smallest true De values (Olley et al., 1999, 2004). To estimate the burial doses associated with the latter population of grains in each sample, we used the 3- parameter minimum age model (MAM) of Galbraith et al. (1999), detailed in Appendix A. Application of this model was also based on site formation processes, discussed in section 5.1. The total environmental dose rates show little variability between the Grant Hall samples, with the majority of samples falling between 1.03 ± 0.04 and 1.05 ± 0.05 Gy ka-1.

4.2 U/Th Dating of Fossil Tooth Dentine and Calcite Straws

Direct dating of teeth yielded ages between 38.2 ± 0.8 and 72.3 ± 2.2 ka (Table 1). Dating of straw stalactites returned ages spanning 186.4 ± 1.0 to > 500 ka, which are significantly older than the corresponding U/Th ages of teeth and OSL sediment ages. U/Th age determinations and supporting isotopic data are presented in Appendix B (Tables B.1 and B.2).

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4.3 Sediment Analysis

4.3.1 Physical properties All sedimentary sample layers are dark brown to dark yellow brown (10 YR 4/4 and 7.5 YR 3/4) in colour (Table 2). Sand and coarse silt grains are dominated by sub-angular quartz grains (geometric mean 0.30), ranging from angular (0.21) to rounded (0.59) (Table C.1 Appendix C). As reflected in grain size statistics and bulk sediment grain size composition (Table 2), the Grant Hall sediment samples are near symmetrical to strongly finely skewed and are very poorly sorted. All sediment sample layers demonstrate similar cumulative grain size distributions for the <1000 μm fraction (Table C.2 Appendix C). Greater variation is reflected in proportion of coarser grain size fractions through the sequence. Sublayer D/D 66–70 cm has the highest granule (>2000 μm) fraction (51%), followed by the sublayer between layers D and E at D/D 115–116 cm (33%) and sample layer D/D 131–136 cm (31%) (Table 2). The lowest granule fraction of 10% occurs at D/D 58–61 cm. This layer has the highest coarse sand (1000–2000 μm) fraction of 33%, more than three times greater than any other layer.

Thin section examination shows that samples D/D 88–90 cm and D/D 121–130 cm contain bone fragments that have fine-grained hydroxylapatite crystallites and are clay coated (Fig. 3a). In contrast, the uppermost sample (D/D 52–58 cm) contains bone fragments with coarse hydroxylapatite crystallites (Fig. 3b). Bone fragments from this layer have coatings and fillings of micro-calcite. In situ pieces of all three thin sectioned layers show evidence of clay accumulation and movement processes, similar to those observed in surface soils. Much of the sediment is held together by a clay-silt matrix which appear in thin-section as in situ cave soil clods. Structures in these clods include coatings and infilling of cracks and voids by clay, likely carried and deposited by dripping water (Fig. 3c–d). This common process in soils produces the so-called bright clay texture commonly observed in thin sections of soils, and forms from the parallel orientation of clay mineral coatings and is present in many of the soil clods of the Grant Hall sediments. All three thin section samples contain a mix of grain types of quartz sand and silt grains as well as limestone and bone fragments held together by this clay matrix (Fig. 3c–d). The limestone fragments show a variety of textures ranging from totally recrystallised and micritised fragments to relatively pristine fragments where original bryozoan fossils from the Gambier Limestone can be identified. Some limestone clasts show evidence of dissolution as well as calcite or aragonite precipitation. The re-crystallisation of limestone calcite to form micrite (fine-grained homogenous calcium carbonate) invariably incorporated silicate clay minerals alongside calcium carbonate (Fig. 3d).

4.3.2 Major and trace elemental geochemistry SiO2 is the most abundant elemental oxide in the sediments, contributing 54.5–65.6% by weight throughout the deposit (Fig. 4; Table D.1 Appendix D). Al2O3 contents range between 11.8 and 17.8%. Loss on ignition (LOI), which measures the combined contribution of organic matter, the hydrated component of clay and iron minerals and carbonates in the sediment, totals between 9.3 and 14.5%. Fe2O3 content is also high relative to the other measured major elements, ranging 2 from 5.6 to 8.2% and demonstrates a significant positive linear relationship with Al2O3 (R =0.99). With the exception of the uppermost sample (D/D 52–58 cm), SiO2 is negatively correlated with Al2O3, Fe2O3, K2O, MgO and P2O5 (Fig. 5a–f). CaO totals between 3.5 and 11.2% weight, contrasting with the other base cations (Na2O, K2O and MgO) which together make up less than 2% of each sample. P2O5 values range between 0.2 to 0.7%. Ba and Zr have the highest concentrations of the trace elements, ranging from 97 to 133 and 162 to 267 ppm respectively. Sr concentrations are more variable across the deposit than Ni, Y, Nb and Sc, with the highest

7 Archived at Flinders University: dspace.flinders.edu.au concentration of 88 ppm recorded in the uppermost layer D/D 52–58 cm, and the lowest of 45 ppm in the sublayer at D/D 88–90 cm.

Major element scatter plots indicate that the uppermost sample, D/D 52–58 cm is geochemically distinct from the others (Fig. D.1 Appendix D). This sample is characterised by a CaO content of 11.1%, nearly double the next highest value of 6.7% from the sublayer at D/D 115–116 cm. The uppermost sample is also distinguished by low SiO2, Al2O3 and Fe2O3 % contents (54.5, 11.8 and 5.6% respectively), high Sr concentration (88 ppm) and high LOI and TOTC % contents (14.5 and 2.6%) when compared to the other samples.

4.3.3 Comparison with Naracoorte Cave infill sediments and surface deposits Grant Hall sediments are characterised by a greater contribution of the very fine sand to silt grain size fraction when compared to other Naracoorte Cave fills, with the exception of isolated samples from Robertson and Blanche Cave (Table C.3 Appendix C). Brown silts from Robertson Cave, Pit 2, 220 cm (R30) and the reddish brown silts of Pit 3, 340 cm (R32c) are composed of 84 and 81% fine grained material (<300 μm) respectively, comparing strongly with Grant Hall sediments which have an average fine grained fraction of 84 ± 2.2%, excluding D/D 58–61 cm and D/D 66–70 cm. The cumulative distribution curves of sediments from Blanche Cave Pit 1, 38 cm yellowish brown sand (B2) also demonstrate a similar trend to the Grant Hall sediments, with fine sand to silt contributing 78% weight.

Grant Hall sediments are made up of lower SiO2, higher combined Al2O3, Fe2O3 and MgO, TiO2 contents and greater Sc and Y concentrations than other NCWHA cave fills (Fig. 6). These geochemical signatures are more similar to Bool Lagoon Lunettes, Red Brown Earths at the entrance of Robertson Cave and similar Terra Rossa Soils from nearby Joanna and Gartner’s Quarry sites (Mee et al., 2004; Forbes and Bestland, 2007).

5. Discussion

5.1. OSL Chronology

The De distributions reveal that the samples collected from Grant Hall contain quartz grains that experienced similar burial histories. The overdispersion values (35 ± 2% to 44 ± 3%; Table A.3 Appendix A) are much higher than the values of up to 20% commonly considered representative of a single population of well-bleached grains (Jacobs and Roberts, 2007; Arnold and Roberts, 2009). In addition, the De distributions for all samples typically show an asymmetrical shape that extends upwards from a concentration of values around the smallest measured dose (Fig A.2 Appendix A). These distribution patterns, and the observed overdispersion values, are more characteristic of partially bleached samples (Olley et al., 1999; 2004).

We have considered potential mechanisms that could explain these wide De distributions. The incorporation of fully bleached grains, derived from the surface, with partially bleached grains already present within the cave would result in the observed De distribution patterns. Partial bleaching may have occurred following exposure of sediments to scattered light after their initial deposition on the rock pile beneath the solution tube (a narrow entrance passage through the limestone, connecting the surface and the cave chamber). The subsequent movement of grains as a result of secondary transport associated with further sediment deposition or disruption by animals that fell into the cave, could have resulted in fully and partially bleached grains being mixed together inside the cave chamber. Under these conditions, the population of lowest De values within each sample is believed to correspond most closely to the time of deposition of the

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most recently bleached grains (e.g., Prideaux et al., 2010). We determined the De for this population of grains, and used these estimates of burial dose to calculate the OSL age.

The occurrence of articulated and associated bone material, as well as previous taphonomic study of the deposit (Fraser and Wells, 2006), indicates limited post-depositional transport of associated bone material. Sedimentary analyses (discussed in section 5.4) also suggest only minor post- depositional transport and mixing of sediments occurred during accumulation of the deposit. These various lines of evidence suggest that if grain re-transportation had occurred inside the cave, then it is unlikely to represent a significant re-working event or depositional unconformity. On the basis of association of the fossil material and dated sediments, it is expected that the OSL ages provide a reliable estimate of the burial age of bone material. Although OSL age estimates are reported to 1σ following standard convention for this technique, all of the OSL ages overlap within experimental uncertainty at the 2σ level, with the sole exception of GH09-6. This suggests that sediment deposition took place relatively rapidly, but events of only a few millennia in duration, or shorter, cannot be resolved without significantly improved chronological precision.

5.2 U/Th Chronology

Although the teeth and straw stalactites returned U/Th ages that are not internally consistent with stratigraphic superposition, this is not an unexpected result when the open-system geochemical behaviour of tooth dentine and the nature of stalactite accumulation in cave deposits are taken into consideration. The interpretation of the U/Th ages of the teeth is dependent on an understanding of the uptake history of U within the dentine. Uranium migrates into the dentine on one or more occasions after burial, while Th is excluded (Grün et al., 2000; Pike et al. 2002). Thus, although the mode and timing of U uptake can be quite variable, the resulting U/Th date will typically result in a minimum age (i.e., an age younger than the ‘true age’ of the tooth) providing that U has not been subsequently lost from the system (Grün et al., 2000; Pike et al., 2002). The latter may lead to age overestimation. The dentine of the Grant Hall samples shows a weak positive relationship between U concentration and age (Table B.1 Appendix B). That is, the older teeth generally have a higher U concentration than the younger teeth. This is opposite to the pattern expected if U had been recently lost from the system (i.e., the teeth with the oldest ages would have the lowest U concentrations). Moreover, the U/Th age of each tooth falls either within, or is younger than, the error range of the associated OSL ages (Table 1). This supports our interpretation that the teeth have produced reliable minimum U/Th ages.

The proposition that U/Th dating of straw stalactites will provide maximum ages for associated stratigraphic units is based on the assumption that the straws formed prior to, and were incorporated into the deposit during, the main phase of sedimentation (Price et al., 2009; St Pierre et al., 2009). Thus, U/Th dating of such straws will yield maximum ages for the associated sediments. Due to the fact that straw stalactites typically grow quickly and have a short ‘life span’ relative to other speleothems such as flowstones and stalagmites, U/Th ages for straws can yield ages close to the ‘true’ age of the deposit (St Pierre et al., 2009). However, the age of the straws may be older than the depositional age, depending on when the straws initially formed and subsequently fell on to the cave floor. The dated straw stalactites from the Grant Hall fossil deposit are significantly older than both the teeth and sediments and thus, do not provide tighter constraints on the age of the deposit. However, the straws appear to yield reliable maximum ages for the cave and indicate that speleothem deposition occurred during the Middle Pleistocene.

5.3 Chronology of Accumulation

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U/Th ages of basal and capping speleothem deposits provide constraints on the chronology of the Grant Hall fossil and sedimentary accumulation (Moriarty et al., 2000). The basal flowstone formed ca. 206 ka, and the entire deposit is capped by a flowstone dated by U/Th to ca. 76 ka (Moriarty et al., 2000). The preservation of calcite straws much older than the basal flowstone in the deposit indicates that speleothem formation occurred in the cave during much of the Middle Pleistocene.

The fossil assemblage is associated with sediments which were deposited on top of the basal flowstone from 93 ± 8 ka (GH09-6, D/D 136–141 cm). Allowing for the uncertainty associated with the youngest OSL ages in the sequence (70 ± 6 ka and 70 ± 5 ka) at D/D 61–66 cm and D/D 52–58 cm, the OSL chronology conforms to the age of the constraining, capping flowstone. Minimum ages from fossil teeth support the OSL evidence for Late Pleistocene accumulation. Further, the U/Th fossil teeth ages are younger than, or within the error of, the corresponding OSL ages, supporting our interpretation that the burial age of the sediments accords well with the true (depositional) age of the bone material. This assumption would not have been supported if the U/Th tooth ages were older than the corresponding OSL ages.

The OSL chronology is consistent with a multi-grain OSL age estimate of 84 ± 8 ka measured from a single sample from the deposit (Roberts et al., 2001) and does not support the earlier model for accumulation over the peak of the last interglacial (Moriarty et al., 2000). The new chronology indicates that the Grant Hall fossil assemblage dates to the final stages of the last interglacial, from Marine Isotope Stage (MIS) 5b, and, considering the age uncertainty for sample GH09-6, possibly 5c. The OSL ages from the uppermost layers of the sequence suggests accumulation continued into the early stages of the cool stadial, MIS-4, although the U/Th age of the capping flowstone is expected to indicate the cessation of bone and sediment inputs into the cave, ca. 76 ka (Morialty et al., 2000).

5.4 Sediment Analysis

5.4.1 Physical properties Forbes and Bestland (2007) recognised three general sediment types within the Naracoorte Cave deposits: Type I (yellow to grey homogeneous sands), Type II (dark brown to brown organic- matter rich sandy silts) and Type III (reddish brown sandy silts). Analysis of Grant Hall sediment colour, grain roundness and fine grain composition indicates that they are largely homogeneous through the sequence, and are broadly classified as dark brown silty sands with soil structures present, and supports the characterisation of the Grant Hall sediments to Type III by Forbes and Bestland (2007).

Microscopic analysis of the sediments from thin sections suggests that much of the clay accumulated or was re-distributed following the primary phase of sediment deposition. Based on the microstructures of the cave soil clods, it is not thought that these textures and structures were inherited from surface soil fragments. The mix of grain types in the soil clods and the fragile nature of the clayey infilling structures argues for in situ formation at or just below the cave floor. Mechanisms of clay accumulation may have included the settling of dust and clay contained in dripping cave water as well as silicate clay residue from the dissolution of limestone during cave formation (Weiner et al., 2002). Microbial activity and dripping water is likely to account for clay binding and coating of grains. The range of morphologies of the limestone clasts is thought to be due to alteration of fretting cave limestone, re-crystallisation in the sedimentary deposit as well as the incorporation of weathered limestone fragments during sediment accumulation.

5.4.2 Major and trace elemental geochemistry

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Major and trace elemental geochemistry of the Grant Hall sediments indicates that they vary within a moderate range of elemental values compared to other Naracoorte Cave sediments (Fig. 6). The exception is the uppermost layer (D/D 52–58 cm) which is distinguished by high CaO, low Al2O3 and Fe2O3 and low silica content when compared with the other layers. The primary source of Ca into this layer is suggested to be fretting of limestone from the cave roof, as indicated by bryozoan fragments contained within silt matrices of the sediments. The OSL age estimate for this layer suggests that these sediments have been exposed on the surface of the deposit for a minimum of 77 thousand to 67 thousand years (at 1σ error). By comparison, OSL and U/Th ages of fossil teeth indicate that accumulation of the lower layers occurred almost continuously, thus having less time to accumulate CaCO3 via limestone fretting. Bone and speleothem drip waters may also be responsible for a minor amount of Ca in the sediments.

With the exception of the uppermost sediments, high alumina and iron element composition correlates with low SiO2 content in the Grant Hall sediments. This relationship is expected as SiO2 is the main constituent of quartz sand, while Al and Fe are more common in fine grained fractions. However, there is no correlation between alumina and iron contents and percentage silt composition as would be expected (R2 = 0.4 and 0.42 respectively). The Grant Hall sediments show little variation throughout the sequence in the percentage of fine silt composition which may explain why no correlation could be detected. Alternatively, lack of linear relationship may result from the Al and Fe elements being directly tied to the clays, rather than the fine grain fractions that have accumulated from regional and local sources. When Naracoorte Cave sedimentary deposits from different sites are plotted together, a linear relationship between silt 2 2 content and alumina and iron emerges, although it is not strong (Al2O3: R = 0.61; Fe2O3: R = 0.64).

5.4.3 Stratigraphic profile The primary aim of analysis of the Grant Hall sediments was to determine the number and character of sedimentary units within the deposit. The analysis was framed around contrasting models of the stratigraphic division of the deposit. Detailed characterisation of the physical properties of the sediments indicates that the Grant Hall sequence is composed of largely homogeneous dark brown silty sands, although there is variation in the composition of the coarser sand and larger gravel fractions between samples. This variation is also reflected in the >1 cm diameter gravel and rock distributions through the sequence profile as measured by Gresham (2000). This variation, albeit minor, suggests that different depositional and/or transport processes may have occurred over the accumulation history of the deposit; however, determining the primary depositional processes associated with the Grant Hall sequence is challenging. The chamber is unique as sediments and animals were intercepted by a rock pile prior to deposition on the cave floor. In addition, lack of cut and fill structures in the sedimentary profile, and the thick bedding layers (Fig. 2), contrasting with the fine sedimentary laminations evident in Robertson and Blanche Caves (Forbes et al., 2007; Darrénougué et al., 2009), argues against sediment transport by water flows in Grant Hall.

In contrast to the findings of Fraser and Wells (2006), the two previously identified sublayers across the sequence (sublayers Ba and Ca) are not physically or geochemically distinct from the other sedimentary layers. The additional sublayer identified in the pilot study (Da) is also similar to the main sedimentary layers. Despite the limited physical or geochemical distinctness of these sublayers, their presence is expected to indicate minor hiatus and/or changes in accumulation processes over the depositional history and thus, provide a basis for division of the stratigraphic sequence. Layers B, C and D are interpreted as discrete depositional units (Unit B: D/D 58–66 cm; Unit C: D/D 70–88 cm; Unit D: D/D 90–115 cm), divided by these sublayers. Layer A is also interpreted as discrete unit based on the unique geochemical composition of sediments from this

11 Archived at Flinders University: dspace.flinders.edu.au section of the profile (Unit A: D/D 52–58 cm). By comparison, lack of physical and/or geochemical variability between the sediments in layers E and F, as well as the absence of a sedimentary demarcation between these sections of the profile, suggests that they be considered as a single depositional unit, Unit E (D/D 116–143 cm). Overlap in the OSL ages through the deposit means that temporally constraining these depositional units is difficult. However, based on the sedimentary analysis, definition of these units is expected to provide the most parsimonious way of temporally constraining fossil faunas through the profile.

5.4.4 Comparison with Naracoorte Cave infill sediments and surface deposits As no other cave in the World Heritage Area is known to coincide with accumulation of Grant Hall during the last interglacial, the physical and geochemical properties of the sediments may be expected to reflect prevailing conditions not represented in other caves. This is supported by the unique geochemical and grain size composition of Grant Hall sediments when compared with other Naracoorte cave fills. By comparison, the sediments share similarities with regional Terra Rossa Soils and/or Bool Lagoon Lunette deposits and may indicate their potential provenance from these surface deposits.

Local Terra Rossa Soils were deposited, at least in part, over the peak of the last interglacial and are derived from aeolian transported dusts of the western playa-lunettes of Bool Lagoon (Mee et al., 2004). This process may account for the high proportion of fines in the Grant Hall sediments which accumulated from within ca. 30 thousand years of this time. However, local effective rainfall records from cave speleothems suggests that the final stages of the last interglacial were relatively wet when compared to peak interglacial conditions ca. 125 ka (Ayliffe et al., 1998; Bestland and Rennie, 2006). As aeolian sediment movement was more commonly associated with arid phases associated with glacial periods (e.g. Hesse et al., 2004; Gingele et al., 2007), it is unlikely the Grant Hall sediments were derived directly from aeolian transport of silts from Bool Lagoon, as modelled for the regional Terra Rossa Soils (Mee et al., 2004). Rather, it is more likely that silts were transported into the Grant Hall deposit from sources proximal to the cave entrance. These proximal sources are expected to have accumulated either during the phase of aeolian transport over the peak of the last interglacial associated with formation of regional deposits such as Joanna and Gartner’s quarry (Mee et al., 2004), or much earlier.

The fine-grained fractions of local Terra Rossa Soils and Bool Lagoon lunettes have been linked by strontium isotopic ratios (87Sr/86Sr) to the Kanmantoo shales of Kangaroo Island and the Fleurieu Peninsula (Mee et al., 2004). However, this suggested provenance has been challenged by Forbes and Bestland (2007) who found that clays and silts of the Bool Lagoon lunettes were more similar to those of the Murray Darling Basin. Recent analysis of neodymium isotopic ratios (143Nd/144Nd) from Blanche Cave sediments supports the earlier finding of Mee et al. (2004), identifying the Kanmantoo Group outcroppings of the Mount Lofty Ranges and Padthaway Ridge as the ultimate source of sediments into 3rd Chamber (Darrénougué et al., 2009). In comparison to the Grant Hall sediments which share some similarities with silts from Bool Lagoon lunettes, provenance of the Blanche Cave sediments from the Kanmantoo shales suggest a different prevailing wind direction during MIS-3 and -2 when compared to MIS-5. Analysis of strontium and/or neodymium isotopes in the Grant Hall sediments would be valuable for determining the ultimate provenance of the fines in this deposit and may provide more information about prevailing wind directions at the time of accumulation. Forbes and Bestland (2007) note that while many of the NCWHA infill sediments may be derived from local surface deposits, it is likely that both cave infill sediments and surface deposits originated from the same ultimate source and developed over the same period of time. This relationship in the south east region provides a means of refining and/or validating the understanding of palaeoenvironmental conditions through the Pleistocene inferred from both cave and surface deposits. This is in

12 Archived at Flinders University: dspace.flinders.edu.au contrast to a karst cave system in Bermuda where sedimentary deposits within caves and fissures of the limestone are not contemporaneous with surface deposits (Hearty et al., 2004), highlighting the unique nature of the south east karst system.

5.4.5 Palaeoenvironmental Implications Speleothem records indicate that Grant Hall sampled fauna during a relatively moist phase following dry conditions associated with peak interglacial conditions. Temperatures during the peak of the last interglacial ca. 125 ka were between 1 and 3°C warmer than present (Anderson et al., 2007), evidenced in the presence of wet rainforest vegetation communities in western Tasmania over this period (Colhoun, 2000). Lack of speleothem growth in the Naracoorte caves at this time is suggested to be the result of higher temperatures and subsequently higher evaporation and reduced effective moisture availability (Ayliffe et al., 1998; Demarshelier et al., 2000). Inversely, temperature declines during glacials and cool interstadials may have ‘depressed’ evapotranspiration, subsequently increasing effective moisture availability. This is supported by pollen deposits in western Tasmania that indicate a temperature reduction from full interglacial conditions of greater than 3.5°C during the cool interstadial ca. 85 ka, coincident with a period of speleothem growth at Naracoorte (Ayliffe et al., 1998; Colhoun, 2000).

The pollen record of marine core E55-6, collected from near-shore western Victoria also contrasts with the speleothem record, indicating wet sclerophyll forest of Eucalyptus with a distinct understorey of Acacia melanoxylon, Olearia, Bedfordia, Pomaderris and tree ferns during the peak of the last interglacial (Harle, 1997). Although this conflicts with the local speleothem record which reflects reduced effective moisture availability at this time, it is expected that variation in climatic conditions at a local scale may limit the accuracy of regional palaeoenvironmental records to specific localities. By comparison, evidence to support the increase in effective precipitation ca. 90 ka from the Naracoorte speleothem record is provided in the short term re-occurrence of wet forest species in the E55-6 core and at Lakes Bolac and Turangmoroke in south western Victoria (Cook, 2009). As discussed by Fraser and Wells (2006), the impact of these changes in moisture availability and regional vegetation communities is evident in the faunal assemblage. Most significant is the apparent absence of M. fuliginosus/giganteus in the Grant Hall deposit, which is the most abundant macropodid in older sites of the NCWHA (Fraser and Wells, 2006). Previous palaeoenviromental reconstruction based on the composition of the faunal assemblage identified well-forested woodlands with dense understorey proximal to the cave entrance (Fraser and Wells, 2006). Under the previous model for accumulation over the peak of the last interglacial, this interpretation was at odds with the local speleothem record. However, the refined chronology and stratigraphic description of the site provides a tighter constraint on accumulation of the fossil assemblage and has improved the resolution at which fossil faunas may be compared through the sequence and with other palaeoenvironmental records. Determining the extent to which the assemblage represents species and/or community level response to warm, wet conditions at the end of the last interglacial requires further examination of the fauna based on an increased sample from this deposit.

6. Conclusions

Application of multiple dating techniques (OSL dating of sediments, U/Th dating of fossil teeth and calcite straws) with detailed sedimentary analyses has enabled the chronological and sedimentary context of the Grant Hall fossil assemblage to be established. Age estimates from OSL dating of clastic inputs and U/Th dating of fossil teeth indicate that the Grant Hall sequence accumulated rapidly over the Late Pleistocene, coinciding with the end of the last interglacial from at least MIS-5b to MIS-5a. This represents a more recent accumulation history than previously suggested for the deposit, but is consistent with the model of rapid accumulation

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(Moriarty et al., 2000). Sediments through the sequence are similar in colour and fine grain composition, and are broadly classified as dark brown sandy silts with soil structures present. Geochemical profiling indicates that the fine silts and clays may be derived from Bool Lagoon lunettes, but the ultimate provenance is unknown. Five depositional units, A to E are defined from these analyses, contrasting with the earlier interpretation of three units by Fraser and Wells (2006) and six in the pilot investigation. This revised chronology and stratigraphy for the deposit provides a framework for more detailed and accurate examination of the fossil faunas within the deposit.

Acknowledgements ACM would like to thank Grant Gully for assistance with preparation of figures for the manuscript, Steve Bourne and members of the Flinders University Palaeontology Laboratory for ongoing support throughout the duration of the project and the South Australian Department of Environment and Natural Resources and Commonwealth Department of the Environment, Water, Heritage and the Arts who provided permits for the collection of sediment and bone material from the site. Funding for the study was provided by the Flinders University School of Biological Sciences Honours Scholarship to ACM, Australian Research Council via DP0772943 to GJPrideaux and DP0881279 to GJPrice. NJR and RGR thank the ARC and The University of Wollongong for funding support. Thanks are also extended to two anonymous reviewers and Colin Murray-Wallace for constructive and insightful comments which greatly improved the manuscript.

Supplementary Information Appendix A: OSL Dating Supplementary Methods, Results and Discussion Appendix B: U/Th age determinations and supporting isotopic data Appendix C: Cumulative grain size distribution (<1000 μm fraction) Appendix D: Geochemical Composition of Grant Hall Sediment Samples

References Aitken, M.J., 1998. An introduction to optical dating: the dating of Quaternary sediments by the use of photon-stimulated luminescence. Oxford University Press, Oxford, 280 pp. Anderson, D.E., Goudie, A.S., Parker, A.G. 2007. Global environments through the Quaternary: Exploring environmental change. Oxford University Press, Oxford, 372 pp. Arnold, L.J., Roberts, R. G., 2009. Stochastic modelling of multi-grain equivalent dose (De) distributions: Implications for OSL dating of sediment mixtures. Quaternary Geochronology 4, 204–230. Ayliffe, L., Veeh, H.H., 1988. Uranium-series dating of speleothems and bones from Victoria Cave, Naracoorte, South Australia. Chemical Geology (Isotope Geoscience Section) 72, 211–234. Ayliffe, L.K., Marianelli, P.C., Moriarty, K.C., Wells, R.T., McCulloch, M.T., Mortimer, G.E., Hellstrom, J.C., 1998. 500 ka precipitation record from southeastern Australia: evidence for interglacial relative aridity. Geology 26, 147–150. Bacon, A., Demeter, F., Duringer, P., Helm, C., Bano, M., Vu The Long, Nguyen Thi Kim Thuy, Antoine, P.-O., Bui Thi Mai, Nguyen Thi Mai Huong, Dodo., Y., Chabaux, F., Rihs, S., 2008. The Late Pleistocene Duoi U-Oi cave in northern Vietnam: palaeontology, sedimentology, taphonomy and palaeoenvironments. Quaternary Science Reviews 27, 1627–1654. Belperio, A.P., 1995. Quaternary. In Drexel, J.F., Preiss, W.V. (Eds.), Geology of South Australia. Volume 2. The Phanerozoic. Geological Survey Bulletin 54, 219–280.

14 Archived at Flinders University: dspace.flinders.edu.au

18 13 Bestland, E.A., Rennie, J., 2006. Stable isotope record (δ O and δ C) of a Naracoorte Caves speleothem (Australia) from before and after the Last Interglacial. Alcheringa Special Issue 1, pp. 19–29. Boggs, S., 1995. Principles of sedimentology and stratigraphy (2nd ed.). Prentice Hall, New Jersey, 784 pp. Colhoun, E.A., 2000. Vegetation and climate change during the Last Interglacial – Glacial cycle in western Tasmania, Australia. Palaeogeography, Palaeoclimatology, Palaeoecology 155, 159–209. Cook, E.J., 2009. A record of late Quaternary environments at lunette-lakes Bolac and Turangmoroke, Western Victoria, based on pollen and a range of non-pollen palynomorphs. Review of Palaeobotany and Palynology 153, 185–224. Darrénougué, N., De Deckker, P., Fitzsimmons, K.E., Norman, M.D., Reed, L., van der Kaars, S., Fallon, S., 2009. A Late Pleistocene record of aeolian sedimentation in Blanche Cave, Naracoorte, South Australia. Quaternary Science Reviews 28, 2600–2615. Demarshelier, J.M., Goede, A., Ayliffe, L.K., McCulloch, M.T., Moriarty, K., 2000. Stable isotope record and its palaeoenvironmental interpretation for a late Middle Pleistocene speleothem from Victoria Fossil Cave, Naracoorte, South Australia. Quaternary Science Reviews 19, 763–774. Denniston, R.F., Gonzalez, L.A., Semken Jr., H.A., 1999. Integrating stalagmite, vertebrate, and pollen sequences to investigate Holocene vegetation and climate change in the southern Midwestern United States. Quaternary Research 52, 381–387. Forbes, M.S., Bestland, E.A., 2007. Origin of the sedimentary deposits of the Naracoorte Caves, South Australia. Geomorphology 86, 369–392. Forbes, M.S., Bestland, E.A., Wells, R.T., Krull, E.S., 2007. Palaeoenvironmental reconstruction of the Late Pleistocene to Early Holocene Robertson Cave sedimentary deposit, Naracoorte, South Australia. Australian Journal of Earth Sciences 54, 541–559. Fraser, R.A., Wells, R.T., 2006. Palaeontological excavation and taphonomic investigation of the Late Pleistocene fossil deposit in Grant Hall, Victoria Fossil Cave, Naracoorte, South Australia. Alcheringa Special Issue 1, 147–161. Galbraith, R.F., Roberts, R.G., Laslett, G.M., Yoshida, H., Olley, J.M., 1999. Optical dating of single and multiple grains of quartz from Jinmium rock shelter, northern Australia: Part 1, experimental design and statistical models. Archaeometry 41, 339–364. Gingele, F., De Deckker, P., Norman, M., 2007. Late Pleistocene and Holocene climate of SE Australia reconstructed from dust and river loads deposited offshore the River Murray Mouth. Earth and Planetary Science Letters 255, 257–272. Gresham, R., 2000. A palaeontological investigation of the Uranium-series dated deposit in Grant Hall chamber, Naracoorte Caves, South Australia. Hons. Thesis, Flinders University of South Australia, South Australia, Australia. Grün, R., Spooner, N.A., Thorne, A., Mortimer, G., Simpson, J.J., McCulloch, M.T., Taylor, L., Curnoe, D., 2000. Age of the Lake Mungo 3 skeleton, reply to Bowler and Magee and to Gillespie and Roberts. Journal of Human Evolution 38, 733–741. Grün, R., Moriarty, K., Wells, R. 2001. Electron spin resonance dating of the fossil deposits in the Naracoorte Caves, South Australia. Journal of Quaternary Science 16, 49–59. Harle, K.J., 1997. Late Quaternary vegetation and climate change in southeastern Australia: palynological evidence from marine core E55-6. Palaeogeography, Palaeoclimatology, Palaeoecology 131, 465–483. Hearty, P.J., Olson, S.L., Kaufmann, D.S., Lawrence Edwards, R., Hai Cheng, 2004. Stratigraphy and geochronology of pitfall accumulations in cave and fissures, Bermuda. Quaternary Science Reviews 23, 1151–1171. Hesse, P.P., Magee, J.W., van der Kaars, S., 2004. Late Quaternary climates of the Australian arid zone: a review. Quaternary International 118-119, 87–102.

15 Archived at Flinders University: dspace.flinders.edu.au

Jacobs, Z., Duller, G. A. T., Wintle, A. G., 2003. Optical dating of dune sand from Blombos Cave, South Africa: II-single grain data. Journal of Human Evolution 44, 613–625. Jacobs, Z., Duller, G. A. T., Wintle, A. G., 2006a. Interpretation of single grain De distributions and calculation of De. Radiation Measurements 41, 264–277. Jacobs, Z., Wintle, A. G., Duller, G. A. T., 2006b. Evaluation of SAR procedures for De determination using single aliquots of quartz from two archaeological sites in South Africa. Radiation Measurements 41, 520–533. Jacobs, Z., Roberts, R.G., 2007. Advances in optically stimulated luminescence dating of individual grains of quartz from archeological deposits. Evolutionary Anthropology 16, 210–223. Ludbrook, N.H., 1961. Stratigraphy of the Murray Basin in South Australia. South Australian Department of Mines Geological Survey of South Australia, Bulletin no. 36, pp. 96. Macken, A.C., 2009. Palaeoecological investigation of the Grant Hall fossil deposit, Victoria Fossil Cave, Naracoorte, South Australia. Hons Thesis, Flinders University of South Australia, South Australia, Australia. Matthews, P.G., 1985. Australian Karst Index 1985 Map Numbering Guide (4th ed.). Australian Speleological Federation, Melbourne, pp 9. Mee, A.C., Bestland, E.A., Spooner, N.A., 2004. Age and origin of Terra Rossa Soils in the Coonawarra area of South Australia. Geomorphology 58, 1–25. Moriarty, K.C., McCulloch, M.T., Wells, R.T., McDowell, M.C., 2000. Mid-Pleistocene cave fills, megafaunal remains and climate change at Naracoorte, South Australia: towards a predictive model using U-Th dating of speleothems. Palaeogeography, Palaeoclimatology, Palaeoecology 159, 113–145. Murray, A.S., Roberts, R.G., 1998. Measurement of the equivalent dose in quartz using a regenerative-dose single-aliquot protocol. Radiation Measurements 29, 503–515. Murray, A.S., Wintle, A.G., 2000. Luminescence dating of quartz using an improved single- aliquot regenerative-dose protocol. Radiation Measurements 32, 57–73. Murray-Wallace, C.V., Brooke, B.P., Cann, J.H., Belperio, A.P., Bourman, R.P., 2001. Whole- rock aminostratigraphy of the Coorong Coastal Plain, South Australia: towards a 1 million year record of sea-level highstands. Journal of the Geological Society 158, 111–124. Olley, J.M., Caitcheon, G.G., Roberts, R.G., 1999. The origin of dose distributions in fluvial sediments, and the prospect of dating single grains from fluvial deposits using optically stimulated luminescence. Radiation Measurements 30, 207–217. Olley, J.M., Pietsch, T., Roberts, R.G., 2004. Optical dating of Holocene sediments from a variety of geomorphic settings using single grains of quartz. Geomorphology 60, 337–358. Pike, A.W.G., Hedges, R.E.M., Van Calsteren, P., 2002. U-series dating of bone using the diffusion-adsorption model. Geochimica et Cosmochimica Acta 66, 4273–4286. Powers, M.C., 1953. A new roundness scale for sedimentary particles. Journal of Sedimentary Petrology 23, 117–119. Prescott, J.R., Hutton, J.T., 1994. Cosmic ray contributions to dose rates for luminescence and ESR dating: large depths and long-term time variations. Radiation Measurements 23, 497– 500. Price, G.J., Zhao, J.-x., Feng, Y.-x., Hocknull, S.A., 2009. New U/Th ages for Pleistocene megafauna deposits of southeastern Queensland, Australia. Journal of Asian Earth Sciences 34, 190–197. Price, G.J., Webb, G.E., Zhao, J.-x., Feng, Y.-x., Murray, A.S., Cooke, B.N., Hocknull, S.A., Sobbe, I.H., 2011. Dating megafaunal extinction on the Pleistocene Darling Downs, eastern Australia: the promise and pitfalls of dating as a test of extinction hypotheses. Quaternary Science Reviews 30, 899-914. Prideaux, G.J., 2006. Mid-Pleistocene vertebrate records: Australia. In Elias, S. (Ed.), Encyclopedia of Quaternary Science. Elsevier, Oxford, pp. 1518–1537.

16 Archived at Flinders University: dspace.flinders.edu.au

Prideaux, G.J., Roberts, R.G., Megirian, D., Westaway, K.E., Hellstrom, J.C. Olley, J.M., 2007. Mammalian responses to Pleistocene climate change in southeastern Australia. Geology 35, 33–36. Prideaux, G.J., Gully, G.A., Couzens, A.M.C., Ayliffe, L.K., Jankowski, N.R., Jacobs, Z., Roberts, R.G., Hellstrom, J.C., Gagan, M.K., Hatcher, L.M., 2010. Timing and dynamics of Late Pleistocene mammal extinctions in southwestern Australia. Proceedings of the National Academy of Sciences of the USA 107, 22157–22162. Reed, E.H., 2003. Taphonomy of large mammal bone deposits, Naracoorte Caves. Ph.D. Thesis, Flinders University of South Australia, South Australia, Australia. Reed, E.H., Bourne, S.J. 2000. Pleistocene fossil vertebrate sites of the south east region of South Australia. Transactions of the Royal Society of South Australia 124, 61–90. Roberts, R.G., Flannery, T.F., Ayliffe, L.K., Yoshida, H., Olley, J.M., Prideaux, G.J., Laslett, G.M., Baynes, A., Smith, M.A., Jones, R., Smith, B.L., 2001. New ages for the last Australian megafauna: continent-wide extinction about 46,000 years ago. Science 292, 1888–1892. Sprigg, R.C., 1952. The geology of the south-east province, South Australia, with special reference to Quaternary coast-line migrations and modern beach developments. South Australian Department of Mines Geological Survey of South Australia, Bulletin no. 29, pp. 120. St Pierre, E., Zhao, J.-x, Reed, E., 2009. Expanding the utility of Uranium-series dating of speleothems for archaeological and palaeontological applications. Journal of Archaeological Science 36, 1416–1423. Turney, C. S. M., Flannery, T. F., Roberts, R. G., Reid, C., Fifield, L. K., Higham, T. F. G., Jacobs, Z., Kemp, N., Colhoun, E. A., Kalin, R. M. Ogle, N., 2008. Late-surviving megafauna in Tasmania, Australia, implicate human involvement in their extinction. Proceedings of the National Academy of Sciences 105, 12150–12153. Wells, R.T., Moriarty, K., Williams, D.L.G., 1984. The fossil vertebrate deposits of Victoria Fossil Cave, Naracoorte: an introduction to the geology and fauna, The Australian Zoologist 21, 305–333. White, S.Q. 2005. Karst and landscape evolution in parts of the Gambier Karst Province, southeast South Australia and western Victoria, Australia. PhD Thesis, La Trobe University, Victoria, Australia. Yu, K.-F., Zhao, J.-X., Shi, Q., Chen, T.-G., Wang, P.-X., Collerson, K.D., Liu, T.-S., 2006. U- series dating of dead Porites corals in the South China sea: evidence for episodic coral mortality over the past two centuries. Quaternary Geochronology 1, 129–141. Zhao, J.-x., Hu, K., Collerson, K.D., Xu, H.-k., 2001. Thermal ionization mass spectrometry U- series dating of a hominid site near Nanjing, China. Geology 29, 27–30.

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Table 1 OSL and U/Th age estimates for the Grant Hall fossil deposit. Age determinations for each method are presented in Appendices A and B respectively. U/Th ages for basal and capping flowstones from Moriarty et al. (2000).

OSL age U-Th dentine U-Th calcite D/D (ka ± 1σ) (ka ± 2σ) (ka ± 2σ) Capping flowstone 76.4 ± 0.7 52–58 cm 70 ± 5 49.6 ± 2.1 58–61 cm 57.3 ± 1.1; 38.2 ± 0.8 386 ± 11 61–66 cm 70 ± 6 66–70 cm 70–74 cm 60.5 ± 1.4 74–79 cm 72.3 ± 2.2 409 ± 37 79–84 cm 82 ± 8 186.4 ± 1.0 84–88 cm 88–90 cm 90–94 cm 94–99 cm 99–104 cm 77 ± 6 67.2 ± 2.2 >500; 553 ± 45 104–109 cm 328.7 ± 2.9; 213.6 ± 1.7 109–115 cm 403 ± 12 115–116 cm 116–121 cm 121–130 cm 76 ± 6 130–131 cm 131–136 cm 82 ± 6 136–141 cm 93 ± 8 441 ± 12; 347 ± 10 141–143 cm 416 ± 7; 419 ± 13 Basal Flowstone 206.7 ± 3.1

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Table 2 Colour, bulk grain size distribution and grain size statistics of Grant Hall sediment sample layers. D/D refers to the depth below the primary datum (Fig. 2). Grain size statistics determined for <2000 μm fraction from graphic plots. Standard deviation estimates sorting. Values for all Grant Hall samples represent very poorly sorted sediments. Skewness values represent near symmetrical (+0.1 to -0.1) to fine (+0.3 to +0.1) and strongly finely skewed samples (+1.0 to +0.3). All samples are very platykurtic as reflected in kurtosis values.

Bulk Grain Size Distribution Grain size statistics of <2000 μm fraction (% weight) (D/D) Colour Standard >2000 1000– <1000 Mean Deviation Skewness Kurtosis μm 2000 μm μm (Φ) (Φ) (Φ) 52–58 cm 10 YR 4/4 Dark yellow brown 11.52 7.92 80.56 3.70 2.54 0.06 0.85 58–61 cm 7.5 YR 3/4 Dark Brown 10.35 33.15 56.50 2.57 2.59 0.42 0.71 66–70 cm 7.5 YR 3/4 Dark Brown 50.99 6.35 42.66 3.10 2.32 -0.05 0.78 74–79 cm 7.5 YR 3/4 Dark Brown 13.22 5.55 81.24 3.87 2.48 0.12 0.97 84–88 cm 7.5 YR 3/4Dark Brown 22.12 7.63 70.25 3.53 2.48 0.10 1.03 88–90 cm 7.5 YR 3/4 Dark Brown 19.65 6.60 73.75 3.53 2.47 0.10 0.99 94–99 cm 7.5 YR 3/4 Dark Brown 19.66 8.52 71.82 3.43 2.43 0.06 1.56 104–109 cm 7.5 YR 3/4 Dark Brown 13.91 5.86 80.23 3.60 2.43 0.12 1.10 115–116 cm 10 YR 3/4 Dark yellow brown 33.34 8.26 58.40 3.67 2.36 0.19 0.91 121–130 cm 7.5 YR 3/4 Dark Brown 17.03 9.68 73.29 3.67 2.60 0.06 0.90 131–136 cm 7.5 YR 3/4 Dark Brown 31.01 7.05 61.94 3.63 2.53 0.09 1.00 136–141 cm 7.5 YR 3/4 Dark Brown 16.24 6.73 77.03 3.67 2.51 0.10 1.00

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Fig. 1 a. and b. Location of the Grant Hall fossil deposit in Victoria Fossil Cave (5U1), Naracoorte Caves World Heritage Area (NCWHA), south eastern South Australia. Map of Victoria Fossil Cave modified from CEGSA and Reed (2003). c. Plan view of the Grant Hall chamber indicating position of excavation grids, datum positions and location of solution pipe entrance to chamber (modified from Fraser and Wells, 2006). Grid square 7 (G7) was excavated in the current investigation.

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Fig. 2. Exposed stratigraphic profile of the south western wall of grid square 7 prior to excavation. Six sedimentary layers (A–F) were identified on the basis of visual inspection of sediment colour and texture and the position of three sublayers (Ba, Ca and Da). These layers were used to guide the excavation in intervals of approximately 5 cm measured as depth below datum (D/D). Relative positions of dating samples indicated. Position of sedimentary sample layers indicated with an asterisk (*). Dashed lines indicate potential boundaries between layers but are not indicated by a discrete sedimentary structure.

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Fig. 3. Photomicrographs from thin sections of cave sediments and cave soil from Grant Hall. a. Hollow bone fragment from D/D 121–130 cm in cross polars showing fine-grain crystallites. b. Bone fragment from D/D 52–58 cm (modern cave surface) in cross polars showing bone fragment with coarse crystallites and coated and filled with fine-grained calcite. Bone fragment is in situ within cave soil matrix. c. Cave soil clod from D/D 88–90cm in cross polars with quartz sand and silt grains, extensive calcite micrite, and cracks. d. Close up of c. where box is indicated showing detail of clay filling textures (arrow) and calcite micrite. e and f. Cave soil clod from D/D 52–58 cm with clasts of quartz sand and micritised limestone held together by clay. Much of this is bright indicating clay translocation.

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Fig. 4. Major and trace elemental geochemistry of Grant Hall sediment sample layers.

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Fig. 5. Linear correlation of major and trace elements with SiO2 in the Grant Hall sediment sample layers. a. to e. Sample layer D/D 52–58 cm excluded from the analysis, f. D/D 52–58 cm included in the analysis.

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Fig. 6. Geochemical composition of Naracoorte Cave and regional sediments (Mee et al., 2004; Forbes and Bestland, 2007) based on combined Al2O3, Fe2O3 and MgO % content and a. SiO2 % weight, b. Y concentration (ppm), c. TiO2 % weight and d. Sc concentration (ppm). AM 1 = Grant Hall, D/D 52–58 cm dark yellow brown silt; AM2 = Grant Hall D/D 58–61 cm dark brown silt; AM3 = Grant Hall, D/D 66–70 cm dark brown silt; AM4 = Grant Hall, D/D 74–79 cm dark brown silt; AM5 = Grant Hall, D/D 84–88 cm dark brown silt; AM6 = Grant Hall, D/D 88–90 cm dark brown silt; AM7 = Grant Hall, D/D 94–99 cm dark brown silt; AM8 = Grant Hall, D/D 104– 109 cm dark brown silt; AM9 = Grant Hall, D/D 115–116 cm dark brown silt; AM10 = Grant Hall, D/D 121–130 cm dark brown silt; AM11 = Grant Hall, D/D 131–136 cm dark brown silt; AM12 = Grant Hall, D/D 136–141 cm dark brown silt; B2 = Blanche Cave, Pit 1 38cm yellowish brown sand; B4 = Blanche, Pit1 50cm brown sandy silt; BL1, 2, 4, = Bool Lagoon lunettes; GA5 = Gartner’s Quarry B-horiz./50; GA6 = Gartner’s Quarry B-horiz./60; GA7 = Gartner’s Quarry B-horiz./75; GA8 = Gartner’s Quarry B-horiz./85; GA9 = Gartner’s Quarry B-horiz./100; GA10 = Gartner’s Quarry B-horiz./115; GA11 = Gartner’s Quarry B-horiz./140; GA12 = Gartner’s Quarry B-horiz./150; GH1 = Grant Hall, Pit 1 10cm brown sandy silt; J1 = Joanna Terra Rossa A-horiz./15; J2 = Joanna Terra Rossa A-horiz./30; J3 = Joanna Terra Rossa A-horiz./45; R0 = Robertson, Pit 1 65cm dark brown silt; R12 = Robertson, Pit 1 135cm brown silt; R32c = Robertson, Pit 3 340cm reddish brown silt; R61 = Robertson, Pit 3 460cm dark brown sandy silt; SB2 = Starburst Chamber, Pit B 60cm reddish silt; TRRP = Robertson Cave entrance Red Brown Earth; VF1 = Victoria Fossil, Pit C 20cm yellowish brown sand; VF6 = Victoria Fossil, Pit B 80cm grey yellowish sand; W10 = Wet Cave, Pit 2 225cm reddish brown sandy silt; Wp1h = Wet Cave, Pit 1 40cm dark brown silt.