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It has been estimated that up to 25% of Indigenous human remains held in Australian institutions are unprovenanced. Geochemical tracers like strontium isotope ratios (87Sr/86Sr) have been used globally for over 40 years to discern human provenance and provide independent data to aid in repatriation efforts. To reliably apply this technology, landscape 87Sr/86Sr isotope ratio variability must be quantified. In Australia, only a few studies have used this technique and they are lacking in detail. Here, we present Australia's first regional strontium isotope ratio variability study. We measured strontium isotope ratios in soil, plant, water, and faunal material throughout Cape York, Queensland, the most northerly point of mainland Australia. Results show a close correlation between surface soil leachates, vegetation, surface water, and faunal 87Sr/86Sr results with extremely high values (0.78664) associated with ancient Precambrian geology. Our study suggests that measuring 87Sr/86Sr in soil and plant samples offer a reliable approach for assessing regional Sr isotope distribution, although the inclusion of mammal and freshwater samples is also important to assess exogenous inputs. This study provides an important tool for modern and prehistoric provenance studies and may aid in answering some of Australia's most enduring archaeological questions. [ABSTRACT FROM AUTHOR]

Koalas (Phascolarctidae, Marsupialia) are generally rare components of the Australian fossil record. However, new specimens of fossil koalas were recovered during recent systematic excavations from several eastern Plio-Pleistocene deposits of Queensland, eastern Australia, including the regions of Chinchilla, Marmot and Mt. Etna. The new records are significant in that they extend the temporal and geographic range of Plio-Pleistocene koalas from southern and southeastern Australia, to northeastern central Queensland. We provide the first unambiguous evidence of koalas in the Pliocene Chinchilla Local Fauna (phascolarctid indet, and Ph. ?stirtoni): important additions to an increasingly diverse arboreal mammalian assemblage that also includes tree kangaroos. The persistence of koalas and local extinction of tree kangaroos in the Chinchilla region today suggests that significant habitat and faunal reorganization occurred between the Pliocene and Recent, presumably reflecting the expansion of open woodlands and grasslands. Other koala records from the newly U/Th-dated Middle Pleistocene Marmor and Mt. Etna fossil deposits (Phascolarctos sp. and Ph. ?stirtoni), along with independent palaeohabitat proxies, indicate the former presence of heterogeneous habitats comprised of rainforests, open woodlands and grasslands. The lack of such habitat mosaics in those regions today is likely the product of significant Middle Pleistocene climate change. [ABSTRACT FROM AUTHOR]

Abstract: Numerous high-energy-transported coral reef blocks occur on the outer reef flats of Heron and Wistari reefs at the southern end of the Great Barrier Reef. In a pilot study, five samples from Heron and one from Wistari were collected for high-precision U-series dating by thermal ionization mass spectrometry. Five of the six dated corals yield U-series dates that suggest these corals were killed and transported during the last century. Without precise knowledge of cyclone impacts in the area, it is not possible to unequivocally link these reef blocks to specific cyclones. Nevertheless, this pilot study demonstrates that cyclone-transported coral reef blocks over the past 300 years can be precisely dated to an age uncertainty of ±1–4 years. This opens up the opportunity for high-age-resolution reconstruction of cyclone history and high-precision assessment of the trend and frequency of cyclone occurrences over the past millennium, as well as for a better understanding of anthropogenic impact on cyclone activity. [Copyright &y& Elsevier]

Degradation of inshore water quality associated with catchment modification is threatening global coral reef ecosystems. Coral trace element proxies are widely applied to document the magnitude and timing of historical changes in river runoff and other disturbances. However, conflicting interpretations of commonly used coral proxies (Ba/Ca, Y/Ca and Mn/Ca) complicate their application for examining historical changes in coastal water quality. The exploration of other coral trace element proxies (such as rare earth elements, REE) is limited in space and time, and to few coral genera. This study examined the dynamics of dissolved REE and yttrium (REEY) in the Fitzroy and Burdekin river tributaries and estuaries, Queensland, Australia. In addition, monthly-resolution long-term temporal records of Ba/Ca, Mn/Ca, Y/Ca and REEY proxies were investigated in two Porites and one Cyphastrea coral colonies from the central and southern Great Barrier Reef in order to test the reliability of these proxies to record the variability of river runoff and local anthropogenic disturbances. The results showed large scale removal of REEY (55–86%) in the low salinity mixing zones of both estuaries with significant fractionation of Nd-Yb and Y-Ho, confirming the ability of coral REEY to act as a terrestrial runoff proxy. Coralline Ba/Ca, Y/Ca and Mn/Ca records generally lack coherence with proximal discharge. However, temporal fluctuations of REEY proxies, irrespective of geographic location and coral genus, showed consistent behaviour relative to regional discharge with progressive increase of total REE/Ca and shale normalized Nd/Yb and decrease of Y/Ho during high-flow summer periods. The shifting baselines of REEY proxies in Cyphastrea grown in the turbid water setting of Rat Island effectively captured the timing of Gladstone Port dredging activities. Our findings suggest that shale normalized coral REEY distributions outperformed other commonly used trace element proxies and are robust indicators of changing inshore water quality. Longer-term records of coral REEY, even covering the period before European settlement from the 1850s, may provide a means to identify shifting baselines and evaluate and quantify the impacts of catchment alteration on coastal water quality and specific coral reef communities. [ABSTRACT FROM AUTHOR]

Abstract: A key to understanding Late Pleistocene megafaunal extinction dynamics is knowledge of megafaunal ecological response(s) to long-term environmental perturbations. Strategically, that requires targeting fossil deposits that accumulated during glacial and interglacial intervals both before and after human arrival, with subsequent palaeoecological models underpinned by robust and reliable chronologies. Late Pleistocene vertebrate fossil localities from the Darling Downs, eastern Australia, provide stratigraphically-intact, abundant megafaunal sequences, which allows for testing of anthropogenic versus climate change megafauna extinction hypotheses. Each stratigraphic unit at site QML796, Kings Creek Catchment, was previously shown to have had similar sampling potential, and the basal units contain both small-sized taxa (e.g., land snails, frogs, bandicoots, rodents) and megafauna. Importantly, sequential faunal horizons show stepwise decrease in taxonomic diversity with the loss of some, but not all, megafauna in the geographically-small palaeocatchment. The purpose of this paper is to present the results of our intensive, multidisciplinary dating study of the deposits (>40 dates). Dating by means of accelerator mass spectrometry (AMS) 14C (targeting bone, freshwater molluscs, and charcoal) and thermal ionisation mass spectrometry U/Th (targeting teeth and freshwater molluscs) do not agree with each other and, in the case of AMS 14C dating, lack internal consistency. Scanning electron microscopy and rare earth element analyses demonstrate that the dated molluscs are diagenetically altered and contain aragonite cements that incorporated secondary young C, suggesting that such dates should be regarded as minimum ages. AMS 14C dated charcoals provide ages that occur out of stratigraphic order, and cluster in the upper chronological limits of the technique (∼40–48 ka). Again, we suggest that such results should be regarded as suspicious and only minimum ages. Subsequent OSL and U/Th (teeth) dating provide complimentary results and demonstrate that the faunal sequences actually span ∼120–83 ka, thus occurring beyond the AMS 14C dating window. Importantly, the dates suggest that the local decline in biological diversity was initiated ∼75,000 years before the colonisation of humans on the continent. Collectively, the data are most parsimoniously consistent with a pre-human climate change model for local habitat change and megafauna extinction, but not with a nearly simultaneous extinction of megafauna as required by the human-induced blitzkrieg extinction hypothesis. This study demonstrates the problems inherent in dating deposits that lie near the chronological limits of the radiocarbon dating technique, and highlights the need to cross-check previously-dated archaeological and megafauna deposits within the timeframe of earliest human colonisation and latest megafaunal survival. [Copyright &y& Elsevier]

Major gaps remain in our knowledge of the early history of Homo sapiens in Wallacea. By 70-60 thousand years ago (ka), modern humans appear to have entered this distinct biogeographical zone between continental Asia and Australia. Despite this, there are relatively few Late Pleistocene sites attributed to our species in Wallacea. H. sapiens fossil remains are also rare. Previously, only one island in Wallacea (Alor in the southeastern part of the archipelago) had yielded skeletal evidence for pre-Holocene modern humans. Here we report on the first Pleistocene human skeletal remains from the largest Wallacean island, Sulawesi. The recovered elements consist of a nearly complete palate and frontal process of a modern human right maxilla excavated from Leang Bulu Bettue in the southwestern peninsula of the island. Dated by several different methods to between 25 and 16 ka, the maxilla belongs to an elderly individual of unknown age and sex, with small teeth (only M1 to M3 are extant) that exhibit severe occlusal wear and related dental pathologies. The dental wear pattern is unusual. This fragmentary specimen, though largely undiagnostic with regards to morphological affinity, provides the only direct insight we currently have from the fossil record into the identity of the Late Pleistocene people of Sulawesi., Competing Interests: The authors have declared that no competing interests exist.

The inshore reefs of the Great Barrier Reef (GBR) have undergone significant declines in water quality following European settlement (approx. 1870 AD). However, direct evidence of impacts on coral assemblages is limited by a lack of historical baselines prior to the onset of modern monitoring programmes in the early 1980s. Through palaeoecological reconstructions, we report a previously undocumented historical collapse of Acropora assemblages at Pelorus Island (central GBR). High-precision U-series dating of dead Acropora fragments indicates that this collapse occurred between 1920 and 1955, with few dates obtained after 1980. Prior to this event, our results indicate remarkable long-term stability in coral community structure over centennial scales. We suggest that chronic increases in sediment flux and nutrient loading following European settlement acted as the ultimate cause for the lack of recovery of Acropora assemblages following a series of acute disturbance events (SST anomalies, cyclones and flood events). Evidence for major degradation in reef condition owing to human impacts prior to modern ecological surveys indicates that current monitoring of inshore reefs on the GBR may be predicated on a significantly shifted baseline.