Browsing by Author "Roberts, RG"

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    High-resolution record of vegetation and climate through the last glacial cycle from Caledonia Fen, southeastern highlands of Australia.
    (Wiley-Blackwell, 2007-07) Kershaw, AP; McKenzie, GM; Porch, N; Roberts, RG; Brown, J; Heijnis, H; Orr, ML; Jacobsen, GE; Newallt, PR
    A blocked tributary has provided a rare site of long-term sediment accumulation in montane southeastern Australia. This site has yielded a continuous, detailed pollen record through the last ca. 140000 years and revealed marked vegetation and environmental changes at orbital to sub-millennial scales. Radiocarbon and optically stimulated luminescence (OSL, or optical) ages provide some chronological control for the last ca. 70 000 years. Most of the sediment is inorganic but with well preserved pollen that accumulated under unproductive and probably largely ice-covered lake conditions. The lake was surrounded by low-growing plants with an alpine character. Exceptions include three discrete periods of high organic sedimentation in the basin and forest development in the surrounding catchment. The two major periods of forest expansion are related to the last interglacial and the Holocene, with the third, shorter period considered to represent an interstadial in the early part of Marine Isotope Stage (MIS) 3. The latter part of the last glacial period is characterised by abrupt sub-millennial, amelioration events that may relate to documented global oscillations emanating from the North Atlantic. There are systematic changes through the record that can be partly attributed to basin infilling but the progressive reduction and regional extinction of some plant taxa is attributed to along-term trend towards climatic drying. © 2007, Wiley-Blackwell.
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    Human occupation of northern Australia by 65,000 years ago
    (Springer Nature, 2017-07-20) Clarkson, C; Jacobs, Z; Marwick, B; Fullager, R; Wallis, LA; Smith, MA; Roberts, RG; Hayes, E; Lowe, KM; Carah, X; Florin, SA; McNeil, J; Cox, D; Arnold, LJ; Hua, Q; Huntley, J; Brand, HEA; Manne, T; Fairbairn, AS; Shulmeister, J; Lyle, L; Salinas, M; Page, M; Connell, K; Park, GY; Norman, K; Murphy, T; Pardoe, C
    The time of arrival of people in Australia is an unresolved question. It is relevant to debates about when modern humans first dispersed out of Africa and when their descendants incorporated genetic material from Neanderthals, Denisovans and possibly other hominins. Humans have also been implicated in the extinction of Australia’s megafauna. Here we report the results of new excavations conducted at Madjedbebe, a rock shelter in northern Australia. Artefacts in primary depositional context are concentrated in three dense bands, with the stratigraphic integrity of the deposit demonstrated by artefact refits and by optical dating and other analyses of the sediments. Human occupation began around 65,000 years ago, with a distinctive stone tool assemblage including grinding stones, ground ochres, reflective additives and ground-edge hatchet heads. This evidence sets a new minimum age for the arrival of humans in Australia, the dispersal of modern humans out of Africa, and the subsequent interactions of modern humans with Neanderthals and Denisovans. © 2017 Macmillan Publishers Limited, part of Springer Nature.
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    Mid-Holocene age obtained for nested diamond pattern petroglyph in the Billasurgam Cave complex, Kurnool District, southern India.
    (Academic Press Ltd - Elsevier Science Ltd., 2013-04-01) Taçon, PSC; Boivin, N; Petraglia, M; Blinkhorn, J; Chivas, A; Roberts, RG; Fink, D; Higham, T; Ditchfield, P; Korisettar, R; Zhao, JX
    India has one of the world's largest and most significant bodies of rock paintings and engravings, yet not a single rock art site or image has been directly and accurately dated using radiometric techniques. Here we report on results from the Billasurgam Cave complex near Kurnool in southern India. Although this cave complex has been investigated archaeologically since the late 1800s, it was not until 2008 that a large petroglyph, consisting of the remains of three nested diamond designs on a stalactite, was noted. In order to determine if this petroglyph had been made recently, flowstone was sampled from on top of and below the engraving. Radiocarbon dating revealed a mid-Holocene age of about 5000 cal BP for the petroglyph, but we cannot rule out the possibility that the engraving is several centuries younger. Similar nested diamond designs at some rock painting sites and on a chest core elsewhere in India have been assumed to be Mesolithic. Our result is consistent with this hypothesis, although we note that it also consistent with the creation of the petroglyph in the early Neolithic. We conclude that the Billasurgam engraved diamond design was probably made by Mesolithic foragers of the Kurnool region and is the oldest surviving form of rock art yet directly dated in southern India. © 2013 Elsevier Ltd.
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    Reply to comments on Clarkson et al. (2017) ‘Human occupation of northern Australia by 65,000 years ago’
    (Taylor & Francis, 2018-04-26) Clarkson, C; Roberts, RG; Jacobs, Z; Marwick, B; Fullagar, R; Arnold, LJ; Hua, Q
    We thank the authors for their comments in the previous issue of Australian Archaeology. The 2012– 2015 research at Madjedbebe offers a new and comprehensive look at the early occupation of Sahul and adds substantially to our knowledge of the timing of that event and the behaviour of the first people to enter the region. Establishing occupation of northern Australia by 65 ± 6 thousand years ago (ka, with the uncertainty expressed at 95.4% probability) pushes human presence in the Top End back beyond the earliest ages so far reported for other Australian sites by c. 5,000–15,000 years (Roberts et al. 1994; Hamm et al. 2016; Veth et al. 2017), thus raising interesting questions as to the latitudinal extent of continental occupation prior to 50 ka. © 2018 Australian Archaeological Association