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Articles 31 - 56 of 56
Full-Text Articles in Life Sciences
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.
A Southern Indian Middle Palaeolithic Occupation Surface Sealed By The 74 Ka Toba Eruption: Further Evidence From Jwalapuram Locality 22, Richard Roberts, Allan Chivas, Christopher Clarkson, Ravi Korisettar, Nicole Boivin, Michael Petraglia, Peter Ditchfield, Michael Haslam, Janardhana Bora, Sanjay Eksambekar, Victoria Smith, Anna Oh, Clair Harris
A Southern Indian Middle Palaeolithic Occupation Surface Sealed By The 74 Ka Toba Eruption: Further Evidence From Jwalapuram Locality 22, Richard Roberts, Allan Chivas, Christopher Clarkson, Ravi Korisettar, Nicole Boivin, Michael Petraglia, Peter Ditchfield, Michael Haslam, Janardhana Bora, Sanjay Eksambekar, Victoria Smith, Anna Oh, Clair Harris
Richard G Roberts
No abstract provided.
Single-Grain Osl Chronologies For Middle Palaeolithic Deposits At El Mnasra And El Harhoura 2, Morocco: Implications For Late Pleistocene Human-Environment Interactions Along The Atlantic Coast Of Northwest Africa, Zenobia Jacobs, Richard Roberts, Roland Nespoulet, M El Hajraoui, Andre Debenath
Single-Grain Osl Chronologies For Middle Palaeolithic Deposits At El Mnasra And El Harhoura 2, Morocco: Implications For Late Pleistocene Human-Environment Interactions Along The Atlantic Coast Of Northwest Africa, Zenobia Jacobs, Richard Roberts, Roland Nespoulet, M El Hajraoui, Andre Debenath
Richard G Roberts
Optically stimulated luminescence (OSL) measurements were made on individual, sand-sized grains of quartz from Middle Palaeolithic deposits at two cave sites (El Harhoura 2 and El Mnasra) on the Atlantic coast of Morocco. We were able to calculate OSL ages for 32 of the 33 samples collected from the Middle Palaeolithic deposits, including the earliest and latest Aterian levels at both sites. These ages reveal periods of occupation between about 110 and 95 ka (thousands of years ago), and at ~75 ka. A late Middle Palaeolithic occupation of El Harhoura 2 is also recorded at ~55 ka. Our single-grain OSL …
Testing Times: Old And New Chronologies For The Howieson's Poort And Still Bay Industries In Environmental Context, Richard Roberts, Zenobia Jacobs
Testing Times: Old And New Chronologies For The Howieson's Poort And Still Bay Industries In Environmental Context, Richard Roberts, Zenobia Jacobs
Richard G Roberts
No abstract provided.
Dating The Quaternary: Progress In Luminescence Dating Of Sediments, Richard Roberts, O Lian
Dating The Quaternary: Progress In Luminescence Dating Of Sediments, Richard Roberts, O Lian
Richard G Roberts
No abstract provided.
Melting Ice Sheets 400,000 Yr Ago Raised Sea Level By 13 M: Past Analogue For Future Trends, David Roberts, Panagiotis Karkanas, Zenobia Jacobs, Curtis Marean, Richard Roberts
Melting Ice Sheets 400,000 Yr Ago Raised Sea Level By 13 M: Past Analogue For Future Trends, David Roberts, Panagiotis Karkanas, Zenobia Jacobs, Curtis Marean, Richard Roberts
Richard G Roberts
Marine Isotope Stage (MIS) 11 was possibly the longest (∼423,000–362,000 yr ago) and warmest interglacial of the entire Quaternary Period. This resulted from a special arrangement of Earth's orbital parameters-similar to the present interglacial (MIS 1)-suggesting that MIS 11 provides an analogue for future natural climate forcing and sea levels. Although precise documentation of MIS 11 sea level history is, therefore, crucial – especially considering additional impetus from anthropogenic warming – the maximum MIS 11 sea level remains highly contentious. Estimates from onshore indicators have ranged from below present sea level to about +20 m, resulting from uncertainties in reliability …
Single-Grain Optical Dating Of Grave-Infill Associated With Human Burials At Lake Mungo Australia, Jonathon Olley, Richard Roberts, Hiroyuki Yoshida, James M Bowler
Single-Grain Optical Dating Of Grave-Infill Associated With Human Burials At Lake Mungo Australia, Jonathon Olley, Richard Roberts, Hiroyuki Yoshida, James M Bowler
Richard G Roberts
Recent age constraints on Australia's oldest human remains (Mungo I and III), found at Lake Mungo in western New South Wales, relied on optical dating of sands from the same stratigraphic units as those into which the remains had been inserted (42±3 ka) and those that overlay the graves (38±2 ka), giving a burial age of 40±2 ka. This indirect means of dating the burials was necessary because the original site from which the remains had been excavated had been completely eroded away. At the time of the original excavation of the Mungo III grave, blocks of sediment from the …
Error Variation In Osl Palaeodose Estimates From Singles Aliquots Of Quartz: A Factorial Experiment, Richard Roberts, R.F. Galbraith, Hiroyuki Yoshida
Error Variation In Osl Palaeodose Estimates From Singles Aliquots Of Quartz: A Factorial Experiment, Richard Roberts, R.F. Galbraith, Hiroyuki Yoshida
Richard G Roberts
No abstract provided.
Homo Floresiensis And The Late Pleistocene Environments Of Eastern Indonesia: Defining The Nature Of The Relationship, Kira Westaway, M Morwood, T. Sutikna, M. Moore, A. Rokus, G Van Den Bergh, Richard Roberts, E. Saptomo
Homo Floresiensis And The Late Pleistocene Environments Of Eastern Indonesia: Defining The Nature Of The Relationship, Kira Westaway, M Morwood, T. Sutikna, M. Moore, A. Rokus, G Van Den Bergh, Richard Roberts, E. Saptomo
Richard G Roberts
No abstract provided.
Middle Paleolithic Assemblages From The Indian Subcontinent, Before And After The Toba Super-Eruption, Michael Petraglia, Ravi Korisettar, Nicole Boivin, Christopher Clarkson, Peter Ditchfield, Sacha Jones, Jinu Koshy, Marta Lahr, Clive Oppenheimer, David Pyle, Richard Roberts, Jean-Luc Schwenninger, Lee Arnold, Kevin White
Middle Paleolithic Assemblages From The Indian Subcontinent, Before And After The Toba Super-Eruption, Michael Petraglia, Ravi Korisettar, Nicole Boivin, Christopher Clarkson, Peter Ditchfield, Sacha Jones, Jinu Koshy, Marta Lahr, Clive Oppenheimer, David Pyle, Richard Roberts, Jean-Luc Schwenninger, Lee Arnold, Kevin White
Richard G Roberts
The Youngest Toba Tuff (YTT) eruption, which occurred in Indonesia 74,000 years ago, is one of Earth's largest known volcanic events. The effect of the YTT eruption on existing populations of humans, and accordingly on the course of human evolution, is debated. Here we associate the YTT with archaeological assemblages at Jwalapuram, in the Jurreru River valley of southern India. Broad continuity of Middle Paleolithic technology across the YTT event suggests that hominins persisted regionally across this major eruptive event.
A Dual-Aliquot Regenerative-Dose Protocol (Dap) For Thermoluminescence (Tl) Dating Of Quartz Sediments Using The Light-Sensitive And Isothermally Stimulated Red Emissions, Richard Roberts, Kira Westaway
A Dual-Aliquot Regenerative-Dose Protocol (Dap) For Thermoluminescence (Tl) Dating Of Quartz Sediments Using The Light-Sensitive And Isothermally Stimulated Red Emissions, Richard Roberts, Kira Westaway
Richard G Roberts
No abstract provided.
A Revised Burial Dose Estimation Procedure For Optical Dating Of Young And Modern-Age Sediments, Richard Roberts, Lee Arnold, R.F. Galbraith, S Delong
A Revised Burial Dose Estimation Procedure For Optical Dating Of Young And Modern-Age Sediments, Richard Roberts, Lee Arnold, R.F. Galbraith, S Delong
Richard G Roberts
No abstract provided.
An Arid-Adapted Middle Pleistocene Vertebrate Fauna From South-Central Australia, Richard Roberts, Lee Arnold, John Hellstrom, Gavin Prideaux, Mark Hutchinson, Linda Ayliffe, Walter Boles, Matthew Cupper, Paul Devine, Brad Pillans, John Long
An Arid-Adapted Middle Pleistocene Vertebrate Fauna From South-Central Australia, Richard Roberts, Lee Arnold, John Hellstrom, Gavin Prideaux, Mark Hutchinson, Linda Ayliffe, Walter Boles, Matthew Cupper, Paul Devine, Brad Pillans, John Long
Richard G Roberts
No abstract provided.
Turning Back The Clock On The Extinction Of Megafauna In Australia, Richard Roberts, Barry Brook
Turning Back The Clock On The Extinction Of Megafauna In Australia, Richard Roberts, Barry Brook
Richard G Roberts
No abstract provided.
The Evolving Landscape And Climate Of Western Flores: An Environmental Context For The Archaeological Site Of Liang Bua, Kira Westaway, Richard Roberts, T Sutikna, Michael Morwood, R Drysdale, J Zhao, Allan Chivas
The Evolving Landscape And Climate Of Western Flores: An Environmental Context For The Archaeological Site Of Liang Bua, Kira Westaway, Richard Roberts, T Sutikna, Michael Morwood, R Drysdale, J Zhao, Allan Chivas
Richard G Roberts
The rapidly changing landscape of the eastern Indonesian archipelago has evolved at a pace dictated by its tropical climate and its geological and tectonic history. This has produced accelerated karstification, flights of alluvial terraces, and complex, multi-level cave systems. These cave systems sometimes contain a wealth of archaeological evidence, such as the almost complete skeleton of Homo floresiensis found at the site of Liang Bua in western Flores, but this information can only be understood in the context of the geomorphic history of the cave, and the more general geological, tectonic, and environmental histories of the river valley and region. …
Advances In Optically Stimulated Luminescence Dating Of Individual Grains Of Quartz From Archaeological Deposits, Richard Roberts, Zenobia Jacobs
Advances In Optically Stimulated Luminescence Dating Of Individual Grains Of Quartz From Archaeological Deposits, Richard Roberts, Zenobia Jacobs
Richard G Roberts
No abstract provided.
Afromontane Foragers Of The Late Pleistocene: Site Formation, Chronology And Occupational Pulsing At Melikane Rockshelter, Lesotho, Brian Stewart, Genevieve Dewar, Mike Morley, Robyn Inglis, Mark Wheeler, Zenobia Jacobs, Richard Roberts
Afromontane Foragers Of The Late Pleistocene: Site Formation, Chronology And Occupational Pulsing At Melikane Rockshelter, Lesotho, Brian Stewart, Genevieve Dewar, Mike Morley, Robyn Inglis, Mark Wheeler, Zenobia Jacobs, Richard Roberts
Richard G Roberts
This paper provides a preliminary chronostratigraphic and palaeoenvironmental framework for the Late Pleistocene archaeological sequence at Melikane Rockshelter in mountainous eastern Lesotho. Renewed excavations at Melikane form part of a larger project investigating marginal landscape use by Late Pleistocene foragers in southern Africa. Geoarchaeological work undertaken at the site supports in-field observations that Melikane experienced regular, often intensive, input of groundwater via fissures in the shelter’s rear wall. This strong hydrogeological connection resulted in episodic disturbances of the sedimentary sequence, exacerbated by other processes such as bioturbation. Despite this taphonomic complexity, a robust chronology for Melikane has been developed, based …
Luminescence Characteristics And Dose Distributions For Quartz And Feldspar Grains From Mumba Rockshelter, Tanzania, Luke Gliganic, Zenobia Jacobs, Richard Roberts
Luminescence Characteristics And Dose Distributions For Quartz And Feldspar Grains From Mumba Rockshelter, Tanzania, Luke Gliganic, Zenobia Jacobs, Richard Roberts
Richard G Roberts
Mumba rockshelter is a key archaeological site for the Middle and Later Stone Age occupation of East Africa, but its chronology has remained unresolved. We report the results of a dating study, focussing on the characterisation of the optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL) properties of quartz- and potassium-rich feldspar grains. Quartz has previously proven troublesome for dating in East Africa. We identified five general types of quartz grain behaviour, based on the shapes of their OSL decay and dose–response curves. Dose recovery experiments and measurement of the natural samples revealed particular problems with quartz grains that …
Beneath The Peat: A Refined Pollen Record From An Interstadial At Caledonia Fen, Highland Eastern Victoria, Australia, P. Kershaw, M. Mckenzie, J. Brown, Richard Roberts, S. Van Der Kaars
Beneath The Peat: A Refined Pollen Record From An Interstadial At Caledonia Fen, Highland Eastern Victoria, Australia, P. Kershaw, M. Mckenzie, J. Brown, Richard Roberts, S. Van Der Kaars
Richard G Roberts
No abstract provided.
Single-Grain Osl Dating At La Grotte Des Contrebandiers ('Smugglers' Cave'), Morocco: Improved Age Constraints For The Middle Paleolithic Levels, Richard Roberts, Zenobia Jacobs, Michael Meyer, V Aldeias, M El Hajraoui, H Dibbie
Single-Grain Osl Dating At La Grotte Des Contrebandiers ('Smugglers' Cave'), Morocco: Improved Age Constraints For The Middle Paleolithic Levels, Richard Roberts, Zenobia Jacobs, Michael Meyer, V Aldeias, M El Hajraoui, H Dibbie
Richard G Roberts
Optically stimulated luminescence (OSL) measurements of individual quartz grains are reported for Middle Paleolithic (MP) or Middle Stone Age (MSA) deposits in La Grotte des Contrebandiers, Morocco. Single-grain measurements enable rejection of grains that may lead to under- or over-estimation of age due to malign luminescence properties or remobilisation of grains after burial. We identified the former using a range of experimental procedures and objective rejection criteria. Three post-depositional factors influenced the distribution pattern of equivalent dose (De) values for the remaining single grains: the disintegration of roof spall liberating unbleached, older grains into otherwise well-bleached sediments; the intrusion of …