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Articles 31 - 60 of 224
Full-Text Articles in Life Sciences
New Excavations Of Middle Stone Age Deposits At Apollo 11 Rockshelter, Namibia: Stratigraphy, Archaeology, Chronology And Past Environments, Ralf Vogelsang, Jurgen Richter, Zenobia Jacobs, Barbara Eichhorn, Veerle Linseele, Richard Roberts
New Excavations Of Middle Stone Age Deposits At Apollo 11 Rockshelter, Namibia: Stratigraphy, Archaeology, Chronology And Past Environments, Ralf Vogelsang, Jurgen Richter, Zenobia Jacobs, Barbara Eichhorn, Veerle Linseele, Richard Roberts
Richard G Roberts
This paper presents new information obtained from a recent excavation and reassessment of the stratigraphy, chronology, archaeological assemblages and environmental context of the Apollo 11 rockshelter, which contains the longest late Pleistocene and Holocene archaeological sequence in Namibia. The Middle Stone Age (MSA) industries represented at the site include an early MSA, Still Bay, Howieson's Poort and late MSA. Optically stimulated luminescence (OSL) dating of individual quartz grains yielded numerical ages for the Still Bay and Howieson's Poort, and indicated the presence of a post-Howieson's Poort phase. OSL dating also verified conventional and accelerator mass spectrometry radiocarbon ages for a …
Were Environmental Or Demographic Factors The Driving Force Behind Middle Stone Age Innovations In Southern Africa?, Zenobia Jacobs, Richard G. Roberts
Were Environmental Or Demographic Factors The Driving Force Behind Middle Stone Age Innovations In Southern Africa?, Zenobia Jacobs, Richard G. Roberts
Richard G Roberts
Sir—Past human responses to environmental changes have long interested archaeologists. During the last glacial cycle, southern Africa experienced marked climatic fluctuations, as recorded in ice-core records from West and East Antarctica.
Single-Grain Osl Dating Of Glaciofluvial Quartz Constrains Reid Glaciation In Nw Canada To Mis 6, Martina Demuro, D Froese, Lee Arnold, Richard Roberts
Single-Grain Osl Dating Of Glaciofluvial Quartz Constrains Reid Glaciation In Nw Canada To Mis 6, Martina Demuro, D Froese, Lee Arnold, Richard Roberts
Richard G Roberts
Improved chronological control on the penultimate advance of the Cordilleran Ice Sheet in northwest Canada (the Reid glaciation) is required for a better understanding of late Quaternary palaeoclimatic and palaeoenvironmental change in eastern Beringia. However, reliable dating of glaciation events beyond the last glacial maximum is commonly hindered by a lack of directly dateable material. In this study we (i) provide the first combined minimum and maximum age constraint on the Reid glaciation at Ash Bend, its reference locale in the Stewart River valley, northwestern Canadian Cordillera, using single-grain optically stimulated luminescence dating of quartz; and (ii) compare the timing …
Optical Dating Of Perennially Frozen Deposits Associated With Preserved Ancient Plant And Animal Dna In North-Central Siberia, Richard Roberts, Lee Arnold, F Brock, E Willerslev, A Tikhonov, R Macphee
Optical Dating Of Perennially Frozen Deposits Associated With Preserved Ancient Plant And Animal Dna In North-Central Siberia, Richard Roberts, Lee Arnold, F Brock, E Willerslev, A Tikhonov, R Macphee
Richard G Roberts
No abstract provided.
Ancient Dna Reveals Late Survival Of Mammoth And Horse In Interior Alaska, James Haile, D. Froese, R. Macphee, Richard Roberts, Lee Arnold, Alberto Reyes, Morten Rasmussen, Rasmus Nielsen, Barry Brook, Simon Robinson, Martina Demuro, M. Gilbert, Kasper Munch, Jeremy Austin, Alan Cooper, Ian Barnes, Per Moller, E. Willerslev
Ancient Dna Reveals Late Survival Of Mammoth And Horse In Interior Alaska, James Haile, D. Froese, R. Macphee, Richard Roberts, Lee Arnold, Alberto Reyes, Morten Rasmussen, Rasmus Nielsen, Barry Brook, Simon Robinson, Martina Demuro, M. Gilbert, Kasper Munch, Jeremy Austin, Alan Cooper, Ian Barnes, Per Moller, E. Willerslev
Richard G Roberts
No abstract provided.
Astronomically Calibrated 40ar/39ar Age For The Toba Supereruption And Global Synchronization Of Late Quaternary Records, Michael Storey, Richard Roberts, Mokhtar Saidin
Astronomically Calibrated 40ar/39ar Age For The Toba Supereruption And Global Synchronization Of Late Quaternary Records, Michael Storey, Richard Roberts, Mokhtar Saidin
Richard G Roberts
The Toba supereruption in Sumatra, ∼74 thousand years (ka) ago, was the largest terrestrial volcanic event of the Quaternary. Ash and sulfate aerosols were deposited in both hemispheres, forming a time-marker horizon that can be used to synchronize late Quaternary records globally. A precise numerical age for this event has proved elusive, with dating uncertainties larger than the millennial-scale climate cycles that characterized this period. We report an astronomically calibrated (40)Ar/(39)Ar age of 73.88 ± 0.32 ka (1σ, full external errors) for sanidine crystals extracted from Toba deposits in the Lenggong Valley, Malaysia, 350 km from the eruption source and …
Development Of The Sar Tt-Osl Procedure For Dating Middle Pleistocene Dune And Shallow Marine Deposits Along The Southern Cape Coast Of South Africa, Zenobia Jacobs, Richard Roberts, Terry Lachlan, Panagiotis Karkanas, Curtis Marean, David Roberts
Development Of The Sar Tt-Osl Procedure For Dating Middle Pleistocene Dune And Shallow Marine Deposits Along The Southern Cape Coast Of South Africa, Zenobia Jacobs, Richard Roberts, Terry Lachlan, Panagiotis Karkanas, Curtis Marean, David Roberts
Richard G Roberts
Optically stimulated luminescence (OSL) dating is now commonly used to estimate the depositional age of Quaternary landforms along the southern Cape coast of South Africa. Due to the early onset of dose saturation in the quartz-rich sediments from this region, determining the age of deposits much older than the last three glacio-eustatic sea-level high stands has been a challenge. In this study, we explored the feasibility of using the thermally-transferred OSL (TT-OSL) dating method to obtain ages for aeolian and shallow marine deposits at three different localities that hold promise to further illuminate the long and complex Late Quaternary sea-level …
Ages For The Middle Stone Age Of Southern Africa: Implications For Human Behavior And Dispersal, Zenobia Jacobs, Richard Roberts, Rex Galbraith, Hilary Deacon, Rainer Grun, Alex Mackay, Peter Mitchell, Ralf Vogelsang, Lyn Wadley
Ages For The Middle Stone Age Of Southern Africa: Implications For Human Behavior And Dispersal, Zenobia Jacobs, Richard Roberts, Rex Galbraith, Hilary Deacon, Rainer Grun, Alex Mackay, Peter Mitchell, Ralf Vogelsang, Lyn Wadley
Richard G Roberts
The expansion of modern human populations in Africa 80,000 to 60,000 years ago and their initial exodus out of Africa have been tentatively linked to two phases of technological and behavioral innovation within the Middle Stone Age of southern Africa—the Still Bay and Howieson's Poort industries—that are associated with early evidence for symbols and personal ornaments. Establishing the correct sequence of events, however, has been hampered by inadequate chronologies. We report ages for nine sites from varied climatic and ecological zones across southern Africa that show that both industries were short-lived (5000 years or less), separated by about 7000 years, …
The Biggest Losers, Richard G. Roberts, Barry Brook
The Biggest Losers, Richard G. Roberts, Barry Brook
Richard G Roberts
No abstract provided.
A High-Resolution Record Of Vegetation And Climate Through The Last Glacial Cycle From Caledonia Fen, Southeastern Highlands Of Australia, A Kershaw, G Mckenzie, N Porch, Richard Roberts, J Browne, H Heijnis, M Orr, Geraldine Jacobsen, P Newall
A High-Resolution Record Of Vegetation And Climate Through The Last Glacial Cycle From Caledonia Fen, Southeastern Highlands Of Australia, A Kershaw, G Mckenzie, N Porch, Richard Roberts, J Browne, H Heijnis, M Orr, Geraldine Jacobsen, P Newall
Richard G Roberts
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. 140 000 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 …
An Improved Osl Chronology For The Still Bay Layers At Blombos Cave, South Africa: Further Tests Of Single-Grain Dating Procedures And A Re-Evaluation Of The Timing Of The Still Bay Industry Across Southern Africa, Zenobia Jacobs, Elspeth Hayes, Richard Roberts, Rex Galbraith, Christopher Henshilwood
An Improved Osl Chronology For The Still Bay Layers At Blombos Cave, South Africa: Further Tests Of Single-Grain Dating Procedures And A Re-Evaluation Of The Timing Of The Still Bay Industry Across Southern Africa, Zenobia Jacobs, Elspeth Hayes, Richard Roberts, Rex Galbraith, Christopher Henshilwood
Richard G Roberts
This paper presents a series of new single-grain optically stimulated luminescence (OSL) ages for the Still Bay at Blombos Cave, South Africa, and compares them to previously published OSL, thermoluminescence (TL) and electron-spin resonance (ESR) ages for this site. Details are provided about the measurement and analytical procedures, including a discussion of the characteristics of the OSL signals of individual quartz grains. This forms the basis for further investigations into the sensitivity of the equivalent dose (De) estimates to a range of different analytical approaches, including changes in the size of the test dose, the choice of signal integration interval, …
Natural Variations In The Properties Of Tl And Irsl Emissions From Metamorphic And Volcanic K-Feldspars From East Africa: Assessing Their Reliability For Dating, L Gliganic, Richard Roberts, Z Jacobs
Natural Variations In The Properties Of Tl And Irsl Emissions From Metamorphic And Volcanic K-Feldspars From East Africa: Assessing Their Reliability For Dating, L Gliganic, Richard Roberts, Z Jacobs
Richard G Roberts
The elevated temperature infrared stimulated luminescence (IRSL) and post-IR IRSL signals of potassium (K)-feldspars have recently garnered attention for their minimal rates of anomalous fading. The post-IR IRSL signal has been used to obtain age estimates for geological deposits, mostly in Europe. Studies on the behaviour of the IRSL and post-IR IRSL signals of K-feldspars from a wider range of geographic regions and depositional contexts are needed, particularly for regions where the OSL signal from quartz is poorly behaved. Discrepancies in the literature regarding the behaviours of the IRSL and TL signals of K-feldspars also highlight the need to characterise …
Initial Speleothem Results From Western Flores And Eastern Java, Indonesia: Were Climate Changes From 47 To 5ka Responsible For The Extinction Of Homo Floresiensis?, Richard Roberts, Allan Chivas, T. Sutikna, Michael Morwood, J Zhao, Kira Westaway
Initial Speleothem Results From Western Flores And Eastern Java, Indonesia: Were Climate Changes From 47 To 5ka Responsible For The Extinction Of Homo Floresiensis?, Richard Roberts, Allan Chivas, T. Sutikna, Michael Morwood, J Zhao, Kira Westaway
Richard G Roberts
No abstract provided.
Redating The Advance Of The New Zealand Franz Josef Glacier During The Last Termination: Evidence For Asynchronous Climate Change, Richard Roberts, Christian Turney, Matt Mcglone, J Cooper, J Wilmshurst, N De Jonge, C Prior
Redating The Advance Of The New Zealand Franz Josef Glacier During The Last Termination: Evidence For Asynchronous Climate Change, Richard Roberts, Christian Turney, Matt Mcglone, J Cooper, J Wilmshurst, N De Jonge, C Prior
Richard G Roberts
No abstract provided.
New Ages For Middle And Later Stone Age Deposits At Mumba Rockshelter, Tanzania: Optically Stimulated Luminescence Dating Of Quartz And Feldspar Grains, Luke Gliganic, Zenobia Jacobs, Richard Roberts, M Dominguez-Rodrigo, A Mabulla
New Ages For Middle And Later Stone Age Deposits At Mumba Rockshelter, Tanzania: Optically Stimulated Luminescence Dating Of Quartz And Feldspar Grains, Luke Gliganic, Zenobia Jacobs, Richard Roberts, M Dominguez-Rodrigo, A Mabulla
Richard G Roberts
The archaeological deposits at Mumba rockshelter, northern Tanzania, have been excavated for more than 70 years, starting with Margit and Ludwig Köhl-Larsen in the 1930s. The assemblages of Middle Stone Age (MSA) and Later Stone Age (LSA) artefacts collected from this site constitute the type sequences for these cultural phases in East Africa. Despite its archaeological importance, however, the chronology of the site is poorly constrained, despite the application since the 1980s of several dating methods (radiocarbon, uranium-series and amino acid racemisation) to a variety of materials recovered from the deposits. Here, we review these previous chronologies for Mumba and …
Human Occupation, Adaptation And Behavioural Change In The Pleistocene And Holocene Of South India: Recent Investigations In The Kurnool District, Andhra Pradesh, Richard Roberts, Kevin White, Christopher Clarkson, Jinu Koshy, Ravi Korisettar, Sacha Jones, Clive Oppenheimer, Nicole Boivin, Michael Petraglia, Peter Ditchfield, Janardhana B, Jamie Hampson, Preston Miracle, Kevin Cunningham, M Kasturi Bai, Dorian Fuller, Michael Haslam
Human Occupation, Adaptation And Behavioural Change In The Pleistocene And Holocene Of South India: Recent Investigations In The Kurnool District, Andhra Pradesh, Richard Roberts, Kevin White, Christopher Clarkson, Jinu Koshy, Ravi Korisettar, Sacha Jones, Clive Oppenheimer, Nicole Boivin, Michael Petraglia, Peter Ditchfield, Janardhana B, Jamie Hampson, Preston Miracle, Kevin Cunningham, M Kasturi Bai, Dorian Fuller, Michael Haslam
Richard G Roberts
No abstract provided.
Establishing The Time Of Initial Human Occupation Of Liang Bua, Western Flores, Indonesia, Kira Westaway, Michael Morwood, Richard Roberts, J Zhao, T. Sutikna, E.W. Saptomo, W Rink
Establishing The Time Of Initial Human Occupation Of Liang Bua, Western Flores, Indonesia, Kira Westaway, Michael Morwood, Richard Roberts, J Zhao, T. Sutikna, E.W. Saptomo, W Rink
Richard G Roberts
No abstract provided.
Reconstructing The Geomorphic History Of Liang Bua, Flores, Indonesia: A Stratigraphic Interpretation Of The Occupational Environment, Kira Westaway, T. Sutikna, W. Saptomo, _ Jatmiko, M Morwood, Richard Roberts, D. Hobbs
Reconstructing The Geomorphic History Of Liang Bua, Flores, Indonesia: A Stratigraphic Interpretation Of The Occupational Environment, Kira Westaway, T. Sutikna, W. Saptomo, _ Jatmiko, M Morwood, Richard Roberts, D. Hobbs
Richard G Roberts
No abstract provided.
Low Temperature (Lt) Combustion Of Sediments Does Not Necessarily Provide Accurate Radiocarbon Ages For Site Chronology, F. Brock, D. Froese, Richard Roberts
Low Temperature (Lt) Combustion Of Sediments Does Not Necessarily Provide Accurate Radiocarbon Ages For Site Chronology, F. Brock, D. Froese, Richard Roberts
Richard G Roberts
No abstract provided.
Age Constraints On Pleistocene Megafauna At Tight Entrance Cave In Southwestern Australia, Richard Roberts, L K Fifield, R. Grun, Richard Jones, M Bird, Gavin Prideaux, G Gully, Linda Ayliffe, Richard Cresswell
Age Constraints On Pleistocene Megafauna At Tight Entrance Cave In Southwestern Australia, Richard Roberts, L K Fifield, R. Grun, Richard Jones, M Bird, Gavin Prideaux, G Gully, Linda Ayliffe, Richard Cresswell
Richard G Roberts
No abstract provided.
Geochronology Of Cave Deposits At Liang Bua And Of Adjacent River Terraces In The Wae Racang Valley, Western Flores Indonesia: A Synthesis Of Age Estimates For The Type Locality Of Homo Floresiensis, Richard Roberts, Kira Westaway, J. Zhao, C Turney, M. Bird, W Rink, L. Fifield
Geochronology Of Cave Deposits At Liang Bua And Of Adjacent River Terraces In The Wae Racang Valley, Western Flores Indonesia: A Synthesis Of Age Estimates For The Type Locality Of Homo Floresiensis, Richard Roberts, Kira Westaway, J. Zhao, C Turney, M. Bird, W Rink, L. Fifield
Richard G Roberts
A robust timeframe for the extant cave deposits at Liang Bua, and for the river terraces in the adjoining Wae Racang valley, is essential to constrain the period of existence and time of extinction of Homo floresiensis and other biota that have been excavated at this hominin type locality. Reliable age control is also required for the variety of artifacts excavated from these deposits, and to assist in environmental reconstructions for this river valley and for the region more broadly. In this paper, we summarize the available geochronological information for Liang Bua and its immediate environs, obtained using seven numerical-age …
Preliminary Results Of The Eip Project, Robert G. Bednarik, Giriraj Kumar, Alan Watchman, Richard G. Roberts
Preliminary Results Of The Eip Project, Robert G. Bednarik, Giriraj Kumar, Alan Watchman, Richard G. Roberts
Richard G Roberts
The primary rationale of the Early Indian Petroglyphs Project is to investigate claims of the occurrence of Lower Palaeolithic petroglyphs in central regions of India. Other purposes of this multifacetted research project are to provide new data for the chronology of the Middle and Late Pleistocene hominin history of India; to introduce scientific methods of rock art dating in this country; and to investigate its Lower Palaeolithic stone tool industries. This project, a collaboration of Indian and Australian researchers, was commenced in 2001. It involves archaeological excavations, a range of analytical studies and intensive field surveys, and it will continue …
Kam Die Kultur Aus Afrika?, Richard G. Roberts, Zenobia Jacobs
Kam Die Kultur Aus Afrika?, Richard G. Roberts, Zenobia Jacobs
Richard G Roberts
According to archaeological standards the Blombos Cave was on the south coast of Africa was a rather small dwelling. The footprint measures just over 50 square meters. But what the researchers unearthed in 13 cubic meters of cave floor was enough to revolutionize our knowledge of the history of the human mind. So-called modern behaviour was therefore on much earlier than previously thought. A team led by South African archaeologist Christopher Henshilwood of the African Heritage Research Institute in Cape Town, who also teaches at the University of Bergen (Norway), discovered in the last 15 years in the Blombos Cave …
Would The Australian Megafauna Have Become Extinct If Humans Had Never Colonised The Continent? Comments On 'A Review Of The Evidence For A Human Role In The Extinction Of Australian Megafauna And An Alternative Explanation' By S.Wroe And J.Field, Barry Brook, David Burney, Timothy Flannery, Michael Gagan, Richard Gillespie, Christopher Johnson, Peter Kershaw, John Magee, Paul Martin, Gifford Miller, Benny Peiser, Richard Roberts
Would The Australian Megafauna Have Become Extinct If Humans Had Never Colonised The Continent? Comments On 'A Review Of The Evidence For A Human Role In The Extinction Of Australian Megafauna And An Alternative Explanation' By S.Wroe And J.Field, Barry Brook, David Burney, Timothy Flannery, Michael Gagan, Richard Gillespie, Christopher Johnson, Peter Kershaw, John Magee, Paul Martin, Gifford Miller, Benny Peiser, Richard Roberts
Richard G Roberts
The problem of the worldwide extinction of a diverse assemblage of Late Pleistocene and Holocene large-bodied animals continues to cause debate (Brook and Bowman, 2002; Barnosky et al., 2004; Burney and Flannery, 2005; Koch and Barnosky, 2006). The most recent contribution on the Australian megafaunal extinction (Wroe and Field, 2006), argues for a staggered series of extinctions over multiple glacial cycles, with most megafaunal extinctions predating the arrival of humans and driven primarily by climate change eventually causing a ‘hydrological threshold’ to be breached. At this point, accessible water became too scarce for megafauna to forage successfully. Although Wroe and …
Changing Ideas On The Identity And Stratigraphic Significance Of The Sheep Creek Tephra Beds In Alaska And The Yukon Territory, Northwestern North America, Richard Roberts, Martina Demuro, D Froese, N Pearce, S Preece, W Hart, W Perkins, J Westgate
Changing Ideas On The Identity And Stratigraphic Significance Of The Sheep Creek Tephra Beds In Alaska And The Yukon Territory, Northwestern North America, Richard Roberts, Martina Demuro, D Froese, N Pearce, S Preece, W Hart, W Perkins, J Westgate
Richard G Roberts
No abstract provided.
Catalysts For Stone Age Innovations: What Might Have Triggered Two Short-Lived Bursts Of Technological And Behavioral Innovation In Southern Africa During The Middle Stone Age?, Richard Roberts, Zenobia Jacobs
Catalysts For Stone Age Innovations: What Might Have Triggered Two Short-Lived Bursts Of Technological And Behavioral Innovation In Southern Africa During The Middle Stone Age?, Richard Roberts, Zenobia Jacobs
Richard G Roberts
No abstract provided.
Still Bay And Serrated Points From Umhlatuzana Rock Shelter, Kwazulu-Natal, South Africa, Marlize Lombard, Lyn Wadley, Zenobia Jacobs, Moleboheng Mohapi, Richard Roberts
Still Bay And Serrated Points From Umhlatuzana Rock Shelter, Kwazulu-Natal, South Africa, Marlize Lombard, Lyn Wadley, Zenobia Jacobs, Moleboheng Mohapi, Richard Roberts
Richard G Roberts
No abstract provided.
Stochastic Modelling Of Multi-Grain Equivalent Dose (De) Distributions: Implications For Osl Dating Of Sediment Mixtures, Richard Roberts, Lee Arnold
Stochastic Modelling Of Multi-Grain Equivalent Dose (De) Distributions: Implications For Osl Dating Of Sediment Mixtures, Richard Roberts, Lee Arnold
Richard G Roberts
No abstract provided.
Optically Stimulated Luminescence Dating Of Single And Multiple Grains Of Quartz From Perennially Frozen Loess In Western Yukon Territory, Canada: Comparison With Radiocarbon Chronologies For The Late Pleistocene Dawson Tephra, Richard Roberts, Lee Arnold, Martina Demuro, F Brock, D Froese, C Bronk Ramsey
Optically Stimulated Luminescence Dating Of Single And Multiple Grains Of Quartz From Perennially Frozen Loess In Western Yukon Territory, Canada: Comparison With Radiocarbon Chronologies For The Late Pleistocene Dawson Tephra, Richard Roberts, Lee Arnold, Martina Demuro, F Brock, D Froese, C Bronk Ramsey
Richard G Roberts
No abstract provided.
Population Increase And Environmental Deterioration Correspond With Microlithic Innovations In South Asia Ca. 35,000 Years Ago, Richard Roberts, Lee Arnold, Christopher Clarkson, Jinu Koshy, Ravi Korisettar, Sacha Jones, Nicole Boivin, Michael Petraglia, Marta Lahr, Peter Ditchfield, Mait Metspalu, Hannah James, Dorian Fuller, Michael Haslam, Gyaneshwer Chaubey, Toomas Kivisild
Population Increase And Environmental Deterioration Correspond With Microlithic Innovations In South Asia Ca. 35,000 Years Ago, Richard Roberts, Lee Arnold, Christopher Clarkson, Jinu Koshy, Ravi Korisettar, Sacha Jones, Nicole Boivin, Michael Petraglia, Marta Lahr, Peter Ditchfield, Mait Metspalu, Hannah James, Dorian Fuller, Michael Haslam, Gyaneshwer Chaubey, Toomas Kivisild
Richard G Roberts
No abstract provided.