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Research paper thumbnail of Late Quaternary extraglacial cold-climate deposits in low and mid-altitude Tasmania and their climatic implications

Geomorphology, 2012

ABSTRACT Many Tasmanian deposits previously described as ‘periglacial’ have been described in mor... more ABSTRACT Many Tasmanian deposits previously described as ‘periglacial’ have been described in more detail, re-interpreted and dated. We suggest that ‘periglacial’ has little meaning when applied locally and the term ‘relict cold-climate deposits’ is more appropriate. In this paper we examine the origin and age of relict cold-climate slope deposits, fan alluvium and aeolian sediments in Tasmania, and infer the conditions under which they accumulated.Fan alluvium dating from the penultimate Glacial (OIS 6) and capped by a prominent palaeosol deduced to date to the Last Interglacial (OIS 5e) is present at Woodstock, south of Hobart. Many fan deposits formed before 40 ka or in a period c. 30–23 ka; only a few deposits date to the Last Glacial Maximum in Tasmania, which is defined as spanning the period 23.5–17.5 ka.Slope deposits indicate widespread instability down to present-day sea level throughout the Last Glacial, probably as a result of freeze–thaw in a sparsely vegetated landscape. Layered fine gravel and coarse sand colluvial deposits resembling grèzes litées, produced both by dry deposition and by the action of water, are locally common where jointed siltstone bedrock outcrops. These deposits occur from altitudes of 500 m to near sea level and also in caves and must have formed under sparse vegetation cover, probably by freeze–thaw in extremely dry conditions. They have been radiocarbon dated from 35 to 17.5 cal. ka.Relict dunes and sandsheets are widespread at the margin of the Bassian Plain that once provided a land bridge between Tasmania and the mainland. They are also found in western Tasmania and in areas of inland southern Tasmania that now support wet eucalypt forest and rainforest and receive mean annual rainfall > 1500 mm. In the south they have been dated > 87.5–19 ka and attest to a long period of semi-arid climate in an area extending well to the west and south of the present semiarid zone.We deduce that during most of the Last Glacial anticyclones dominated Tasmania's climate and rain-bearing depressions generally passed south of the land mass. However in the east prominent palaeosols in aeolian deposits, dated between 26.4 ka and 16 ka at different locations, and palaeosols with morphology indicating formation under humid conditions, indicate periods of wetter climate in eastern Tasmania during or close to the LGM, deduced to be the result of easterlies associated with near-coastal depressions in the western Tasman Sea. Such easterlies may also be responsible for short Last Glacial wet periods noted at mainland coastal sites.A plot of ages of all dated deposits reveals an increase of erosion and deposition between 35 and 20 ka, and greater prevalence of aeolian deposits in the 35–15 ka period than earlier in the Last Glacial. There are two possible explanations for this pattern: (1) that aeolian activity increased as the result of climatic effects (e.g. increased windiness); or (2) that shrubland biomass increased after the megafauna were hunted to extinction following human arrival c. 40 ka, causing increased fire frequency, and in the cold dry climate of the late Last Glacial such fires caused increased erosion and increased aeolian accumulation.

Research paper thumbnail of Aeolian–fluvial interaction and climate change: source-bordering dune development over the past ∼100ka on Cooper Creek, central Australia

Quaternary Science Reviews, 2007

This study provides an interpretation of interrelated Quaternary fluvial and aeolian activity rel... more This study provides an interpretation of interrelated Quaternary fluvial and aeolian activity related to climate change on Cooper Creek in the Lake Eyre Basin in southwestern Queensland, central Australia. The extensive muddy floodplain is characterised by buried sandy palaeochannels now almost entirely invisible but stratigraphically connected to source-bordering dunes that emerge as distinctive sandy islands through the floodplain surface. Luminescence dating has identified pronounced periods of fluvial activity represented by abundant sandy alluvium from Marine Isotope Stages (MIS) 8-3. While all these sandy fluvial episodes on Cooper Creek were much more powerful than anything subsequent, they appear to be ranked in order of declining activity. MIS 8-6 saw reworking of almost the entire floodplain whereas subsequent phases of reworking were far less extensive. Source-bordering dunes were derived from active sandy channels in late MIS 5 ($85-80 ka) and mid MIS 3 (50-40 ka). After $40 ka sand-channel activity largely ceased and the floodplains and channels were inundated with mud, isolating the dunes as emergent features. Although aeolian reworking of the upper parts of some dunes has continued to the present, they show remarkable resilience, having survived without appreciable migration for at least 40 ka. Whilst the channels once determined the location of source-bordering dunes, in an interesting role reversal the remnant dunes now determine the position of many contemporary flood-channels and waterholes by deflection and confinement of overbank flows. r

Research paper thumbnail of Origins of Quaternary Coastal Dune Sheets in San Francisco and Monterey Bay, Central California Coast, U.S.A.: Reflecting Contrasts in Shelf Depocenters and Coastal Neotectonics

Journal of Coastal Research, 2015

Research paper thumbnail of Aeolian–fluvial interaction: evidence for Late Quaternary channel change and wind-rift linear dune formation in the northwestern Simpson Desert, Australia

Quaternary Science Reviews, 2006

In central Australia, the most easterly extent of the MacDonnell Ranges border the Simpson Desert... more In central Australia, the most easterly extent of the MacDonnell Ranges border the Simpson Desert dunefield where widely spaced strike ridges intercept and isolate pockets of broad-crested linear dunes that reflect regional changes in Late Quaternary climate, flow regime and channel avulsion. An energetic Todd River reworked the eastern part of Camel Flat basin from 75-65 ka until the Last Glacial Maximum (LGM) when it shifted eastwards, but with some flows persisting through the basin until about 10 ka. Resulting desert surfaces of different age facilitate temporal comparisons of linear dune formation. Fine-grained red dunes, 75-65 ka in age occur on the western floor of the basin and are ramped against the foot-slopes of the range. After the LGM, and especially during the Holocene, the river's departure enabled small, pale-coloured, closely spaced, coarser-textured linear dunes to form on the abandoned floodplain in the eastern basin, their orientation 201 farther west than the larger and older red dunes. This realignment indicates that the Australian wind-whorl shifted southwards some 160 km or 1.51 after the LGM. Linear dunes in the northwestern Simpson Desert were formed by wind rifting involving vertical accretion of sand from a proximal source, not by longdistance sand transport with linear extension. The blocking ranges have caused negligible downwind sediment accumulation over the past 75 ka. r

Articles and book chapters - main list by Gregory Price

Research paper thumbnail of (2017) Recent archaeological research at Saruq al-Hadid, Dubai, U.A.E.

Weeks L., Cable C., Franke K., Newton C., Karacic S., Stepanov I., Roberts J., Price D., David-Cu... more Weeks L., Cable C., Franke K., Newton C., Karacic S., Stepanov I., Roberts J., Price D., David-Cuny H., Bukhash R.M., Boraik M.R.K., Zein H., 2017. Recent archaeological research at Saruq al-Hadid, Dubai, U.A.E. Arabian Archaeology and Epigraphy 28: 31-60.

Research paper thumbnail of Late Quaternary extraglacial cold-climate deposits in low and mid-altitude Tasmania and their climatic implications

Geomorphology, 2012

ABSTRACT Many Tasmanian deposits previously described as ‘periglacial’ have been described in mor... more ABSTRACT Many Tasmanian deposits previously described as ‘periglacial’ have been described in more detail, re-interpreted and dated. We suggest that ‘periglacial’ has little meaning when applied locally and the term ‘relict cold-climate deposits’ is more appropriate. In this paper we examine the origin and age of relict cold-climate slope deposits, fan alluvium and aeolian sediments in Tasmania, and infer the conditions under which they accumulated.Fan alluvium dating from the penultimate Glacial (OIS 6) and capped by a prominent palaeosol deduced to date to the Last Interglacial (OIS 5e) is present at Woodstock, south of Hobart. Many fan deposits formed before 40 ka or in a period c. 30–23 ka; only a few deposits date to the Last Glacial Maximum in Tasmania, which is defined as spanning the period 23.5–17.5 ka.Slope deposits indicate widespread instability down to present-day sea level throughout the Last Glacial, probably as a result of freeze–thaw in a sparsely vegetated landscape. Layered fine gravel and coarse sand colluvial deposits resembling grèzes litées, produced both by dry deposition and by the action of water, are locally common where jointed siltstone bedrock outcrops. These deposits occur from altitudes of 500 m to near sea level and also in caves and must have formed under sparse vegetation cover, probably by freeze–thaw in extremely dry conditions. They have been radiocarbon dated from 35 to 17.5 cal. ka.Relict dunes and sandsheets are widespread at the margin of the Bassian Plain that once provided a land bridge between Tasmania and the mainland. They are also found in western Tasmania and in areas of inland southern Tasmania that now support wet eucalypt forest and rainforest and receive mean annual rainfall > 1500 mm. In the south they have been dated > 87.5–19 ka and attest to a long period of semi-arid climate in an area extending well to the west and south of the present semiarid zone.We deduce that during most of the Last Glacial anticyclones dominated Tasmania's climate and rain-bearing depressions generally passed south of the land mass. However in the east prominent palaeosols in aeolian deposits, dated between 26.4 ka and 16 ka at different locations, and palaeosols with morphology indicating formation under humid conditions, indicate periods of wetter climate in eastern Tasmania during or close to the LGM, deduced to be the result of easterlies associated with near-coastal depressions in the western Tasman Sea. Such easterlies may also be responsible for short Last Glacial wet periods noted at mainland coastal sites.A plot of ages of all dated deposits reveals an increase of erosion and deposition between 35 and 20 ka, and greater prevalence of aeolian deposits in the 35–15 ka period than earlier in the Last Glacial. There are two possible explanations for this pattern: (1) that aeolian activity increased as the result of climatic effects (e.g. increased windiness); or (2) that shrubland biomass increased after the megafauna were hunted to extinction following human arrival c. 40 ka, causing increased fire frequency, and in the cold dry climate of the late Last Glacial such fires caused increased erosion and increased aeolian accumulation.

Research paper thumbnail of Aeolian–fluvial interaction and climate change: source-bordering dune development over the past ∼100ka on Cooper Creek, central Australia

Quaternary Science Reviews, 2007

This study provides an interpretation of interrelated Quaternary fluvial and aeolian activity rel... more This study provides an interpretation of interrelated Quaternary fluvial and aeolian activity related to climate change on Cooper Creek in the Lake Eyre Basin in southwestern Queensland, central Australia. The extensive muddy floodplain is characterised by buried sandy palaeochannels now almost entirely invisible but stratigraphically connected to source-bordering dunes that emerge as distinctive sandy islands through the floodplain surface. Luminescence dating has identified pronounced periods of fluvial activity represented by abundant sandy alluvium from Marine Isotope Stages (MIS) 8-3. While all these sandy fluvial episodes on Cooper Creek were much more powerful than anything subsequent, they appear to be ranked in order of declining activity. MIS 8-6 saw reworking of almost the entire floodplain whereas subsequent phases of reworking were far less extensive. Source-bordering dunes were derived from active sandy channels in late MIS 5 ($85-80 ka) and mid MIS 3 (50-40 ka). After $40 ka sand-channel activity largely ceased and the floodplains and channels were inundated with mud, isolating the dunes as emergent features. Although aeolian reworking of the upper parts of some dunes has continued to the present, they show remarkable resilience, having survived without appreciable migration for at least 40 ka. Whilst the channels once determined the location of source-bordering dunes, in an interesting role reversal the remnant dunes now determine the position of many contemporary flood-channels and waterholes by deflection and confinement of overbank flows. r

Research paper thumbnail of Origins of Quaternary Coastal Dune Sheets in San Francisco and Monterey Bay, Central California Coast, U.S.A.: Reflecting Contrasts in Shelf Depocenters and Coastal Neotectonics

Journal of Coastal Research, 2015

Research paper thumbnail of Aeolian–fluvial interaction: evidence for Late Quaternary channel change and wind-rift linear dune formation in the northwestern Simpson Desert, Australia

Quaternary Science Reviews, 2006

In central Australia, the most easterly extent of the MacDonnell Ranges border the Simpson Desert... more In central Australia, the most easterly extent of the MacDonnell Ranges border the Simpson Desert dunefield where widely spaced strike ridges intercept and isolate pockets of broad-crested linear dunes that reflect regional changes in Late Quaternary climate, flow regime and channel avulsion. An energetic Todd River reworked the eastern part of Camel Flat basin from 75-65 ka until the Last Glacial Maximum (LGM) when it shifted eastwards, but with some flows persisting through the basin until about 10 ka. Resulting desert surfaces of different age facilitate temporal comparisons of linear dune formation. Fine-grained red dunes, 75-65 ka in age occur on the western floor of the basin and are ramped against the foot-slopes of the range. After the LGM, and especially during the Holocene, the river's departure enabled small, pale-coloured, closely spaced, coarser-textured linear dunes to form on the abandoned floodplain in the eastern basin, their orientation 201 farther west than the larger and older red dunes. This realignment indicates that the Australian wind-whorl shifted southwards some 160 km or 1.51 after the LGM. Linear dunes in the northwestern Simpson Desert were formed by wind rifting involving vertical accretion of sand from a proximal source, not by longdistance sand transport with linear extension. The blocking ranges have caused negligible downwind sediment accumulation over the past 75 ka. r

Research paper thumbnail of (2017) Recent archaeological research at Saruq al-Hadid, Dubai, U.A.E.

Weeks L., Cable C., Franke K., Newton C., Karacic S., Stepanov I., Roberts J., Price D., David-Cu... more Weeks L., Cable C., Franke K., Newton C., Karacic S., Stepanov I., Roberts J., Price D., David-Cuny H., Bukhash R.M., Boraik M.R.K., Zein H., 2017. Recent archaeological research at Saruq al-Hadid, Dubai, U.A.E. Arabian Archaeology and Epigraphy 28: 31-60.