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Aboriginal Australians represent one of the longest continuous cultural complexes known. Archaeological evidence indicates that Australia and New Guinea were initially settled approximately 50 thousand years ago (ka); however, little is known about the processes underlying the enormous linguistic and phenotypic diversity within Australia. Here we report 111 mitochondrial genomes (mitogenomes) from historical Aboriginal Australian hair samples, whose origins enable us to reconstruct Australian phylogeographic history before European settlement. Marked geographic patterns and deep splits across the major mitochondrial haplogroups imply that the settlement of Australia comprised a single, rapid migration along the east and west coasts that reached southern Australia by 4945ka. After continent-wide colonization, strong regional patterns developed and these have survived despite substantial climatic and cultural change during the late Pleistocene and Holocene epochs. Remarkably, we find evidence for the continuous presence of populations in discrete geographic areas dating back to around 50ka, in agreement with the notable Aboriginal Australian cultural attachment to their country., Author(s): Ray Tobler [1]; Adam Rohrlach [2, 3]; Julien Soubrier [1, 4]; Pere Bover [1]; Bastien Llamas [1]; Jonathan Tuke [2, 3]; Nigel Bean [2, 3]; Ali Abdullah-Highfold [5]; Shane [...]

A compliance-based excavation on Parramatta River (western Sydney) found evidence of a brief visitation by Aboriginal people during the terminal Pleistocene (c.14 ka), from which an exotic raw material–medium-grained porphyroblastic andalusite-cordierite hornfels–was recovered. This raw material is rare in the region, only found in the Megalong Valley situated some 75 km west of the site in Parramatta, and separated from the site by the Blue Mountains–a 40 km wide, 1 km high dissected sandstone upland. Historical observations and geological evidence suggest that the Coxs River, which runs through the upland, formed the probable connection between the two locales. The formation of the site at c.14 ka, along with our broader understanding of the region, suggests that the upland was only explored after the Last Glacial Maximum (LGM) and that the Great Dividing Range may have formed a significant barrier to early peopling of Sahul. Further, a delay between the end of the LGM and the exploration of the region implies populations were severely affected by the event and required considerable time to recover. The coincident timing of rapid sea-level rise from Meltwater Phase Pulse 1A and an increased supply of moisture associated with the Antarctic Climate Reversal at the time of many site initiations may have been factors in the upland and south west slopes visitation. Finally, the movement of the unusual hornfels artefact provides a coarse indication of the ranging territory for hunter-gatherers living in a temperate region (c. 8,000 km2) at this time. This is probably a lower estimate but begins to provide a quantitative value with which to begin to ratify the increasing divergence between archaeological and genomic studies in their definitions of mobility, sedentism and regional nomadism. [ABSTRACT FROM AUTHOR]

Precise radiocarbon (14C) dating of sedimentary sequences is important for developing robust chronologies of environmental change, but sampling of suitable components can be challenging in highly dynamic landscapes. Here we investigate radiocarbon determinations of different peat size fractions from six peat sites, representing a range of geomorphological contexts on the South Atlantic subantarctic islands of the Falklands and South Georgia. To investigate the most suitable fraction for dating, 112 measurements were obtained from three components within selected horizons: a fine fraction <0.2 mm, a coarse fraction >0.2 mm, and bulk material. We find site selection is critical, with locations surrounded by high-ground and/or relatively slowly accumulating sites more susceptible to the translocation of older carbon. Importantly, in locations with reduced potential for redeposition of material, our results show that there is no significant or systematic difference between ages derived from bulk material, fine or coarse (plant macrofossil) material, providing confidence in the resulting age model. Crucially, in areas comprising complex terrain with extreme relief, we recommend dating macrofossils or bulk carbon rather than a fine fraction, or employing comprehensive dating of multiple sedimentary fractions to determine the most reliable fraction(s) for developing a robust chronological framework. [ABSTRACT FROM AUTHOR]

Anatomically modern humans (Homo sapiens, AMH) began spreading across Eurasia from Africa and adjacent Southwest Asia about 50,000-55,000 years ago (ca. 50-55 ka). Some have argued that human genetic, fossil, and archaeological data indicate one or more prior dispersals, possibly as early as 120 ka. A recently reported age estimate of 65 ka for Madjedbebe, an archaeological site in northern Sahul (Pleistocene Australia-New Guinea), if correct, offers what might be the strongest support yet presented for a pre-55-ka African AMH exodus. We review evidence for AMH arrival on an arc spanning South China through Sahul and then evaluate data from Madjedbebe. We find that an age estimate of >50 ka for this site is unlikely to be valid. While AMH may have moved far beyond Africa well before 50-55 ka, data from the region of interest offered in support of this idea are not compelling. [ABSTRACT FROM AUTHOR]