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

McIntosh, Peter D.; Eberhard, R; Slee, Adrian; Moss, Patrick; Price, David M.; Donaldson, Paul M.; Doyle, RB; Martins, José

doi:10.1016/j.geomorph.2012.08.009

Cited by 26 publications

(40 citation statements)

References 46 publications

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“…The cave appears to have formed by either the complete removal of a column or joint widening by freeze -thaw processes (Slee 2011). Angular stratified scree deposits have been identified by Sharples (1994) and McIntosh et al (2009McIntosh et al ( , 2012 from several low elevation sites in north-eastern Tasmania including near Mathinna in the upper South Esk Valley (6) (Sharples 1994) and near Golconda (7) (McIntosh et al 2012). The fabric and morphology of the stratified scree deposits resemble similar deposits often described as gréze litées from other locations around the globe (e.g.…”

Section: Relict Periglacial Deposits Of North-east Tasmaniamentioning

confidence: 77%

“…During winter frost shatter of the source rock promotes well sorted talus slopes with the coarse material moving the furthest and collecting down slope of finer material (Scapozza et al 2011). During summer rainfall events or summer snowmelt the fine material on the upper slopes of the deposit is reactivated by moisture induced debris flows that bury the coarser material on the lower slopes ( Van Steijn et al 2002, Van Steijn 2011and McIntosh et al 2012. This activity promotes thick accumulations of stratified bedded screes with relict landforms suggested (Karte 1983, Eaton et al 2003, Van Steijn 2011and McIntosh et al 2012) to indicate prevailing sparse vegetation cover of the hill slope during scree formation.…”

Section: Angular Gravel Depositsmentioning

confidence: 99%

“…Boulders dated from low angle blockfields on the Mt Wellington Plateau using cosmogenic nuclide 36 Cl have produced dates up to half a million years (Barrows et al 2004) indicating that the summit plateau is unlikely to have been glaciated since at least this time but has been a site of intense periglacial processes. At Home Hill Vineyard near Grove (16) a thick deposit of fine screes exposed in a landslide back-wall has been dated to the beginning of the LGM (McIntosh et al 2009, McIntosh et al 2012. This deposit of stratified screes draping a hill slope 30 m above the present sea level implies hillslope mass movement under cold climatic conditions that has been thermoluminescence dated to 28 kya, the location of this site in an inland location at the base of the Wellington Range suggests that cold air pooling may have promoted the active periglacial freeze-thaw processes on a sparsely vegetated slope.…”

Section: Relict Periglacial Landforms Of East and South-east Tasmaniamentioning

confidence: 99%

“…Similar stratified screes, several meters thick, has been recently exposed in the Styx Valley (17) at an altitude of 500 m asl (Figure 3.3). The deposit is undated, however a nearby paleosol that appears to lie stratigraphically beneath the scree deposits was radiocarbon dated by McIntosh et al (2012) to 34.9 cal kya suggesting that the overlying scree deposits formed immediately prior to or during the LGM. The deposit is locally faulted demonstrating brittle deformation and may have been frozen.…”

Section: Relict Periglacial Landforms Of East and South-east Tasmaniamentioning

confidence: 99%

“…These environments fit in the definitions of 'periglacial' as proposed by Soons and Price (1990), French (2000), and Matsuoka (2001a); however frost processes can be active in relatively mild environments if significant cold air drainage effects are present on the local scale. McIntosh et al (2012) argue that the term 'periglacial' is too narrow for describing active and relict ground ice and freeze-thaw associated landforms and processes, and they suggest the general title 'Cold climate deposits' or more precisely 'extraglacial cold climate deposits' is more suitable than 'periglacial landforms' for describing a broader range of landforms and processes in Australia.…”

Section: Introduction To Landforms Of Periglacial Originmentioning

confidence: 99%

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The distribution and paleoclimate implications of periglacial landforms in eastern Australia

Slee¹

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It is widely recognised that during the Late Quaternary, glaciation was limited in Australia, especially away from Tasmania. This contrasts with the widely recognised occurrence of periglacial landforms in SE Australia, particularly in Australian Alps and Tasmania.However, very little research has been undertaken into these landforms. The aim of this thesis is to investigate the extent and timing of Late Quaternary periglacial conditions in south-eastern Australia and to understand the geomorphic processes and environments associated with these landforms. This thesis presents an updated understanding of the distribution, morphology and climatic significance of periglacial landforms in eastern Australia. The thesis is divided into two sections. The first section is focused on modern 'active' periglacial landforms found primarily in the mountainous areas of Tasmania and focuses on two studies of modern freeze-thaw processes in western Tasmania. At higher elevations (1000 m) notable freeze-thaw features are active at the present time including stone banked lobes on Mt Rufus. Freeze-thaw features were identified to only 150 m above sea-level near Queenstown. However, these low elevation freeze-thaw landforms are small scale features associated with short periods where shallow ground ice forms.The second section of the thesis focuses on relict periglacial landforms that display no evidence of modern activity and most likely relate to late Quaternary cold climate conditions. It primarily focuses on the block deposits of eastern Australia, their morphology, distribution and climatic significance. Block deposits and associated landslide deposits from northern New South Wales to Tasmania were mapped. Four sites were studied in more detail and dated using surface exposure dating (SED). They yielded ages ranging from early Holocene to OIS 5 which are internally consistent within sites but vary widely between sites. These data provide evidence for repeated phases of periglacial activity during the last glacial cycle. At Guyra, several phases of mass movement were recognised with large scale landslides associated with a much earlier warm and humid climate dominating the landscape. Freeze-thaw landforms of the late Quaternary are superimposed on these older forms. The scale of last glaciation cooling is indicated by evidence for a possible nivation hollow bounded by a pronival rampart located near the town of Guyra (29°30'S). From this site a cooling range of 8-11°C is inferred, but additionally, relatively moist conditions are required for the nivation feature to form.The concept of a relatively humid glaciation also emerges from the mapping of the freezethaw landforms on a regional basis. In particular the occurrence of block deposits and screes in northern New England in patterns matching the modern precipitation gradient indicates that freeze-thaw was preferentially concentrated in a zone parallel to the coast. It is inferred that this zone represented an area of intermediate moisture landward of the divide separa...

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Section: Relict Periglacial Deposits Of North-east Tasmaniamentioning

confidence: 77%

Section: Angular Gravel Depositsmentioning

confidence: 99%

Section: Relict Periglacial Landforms Of East and South-east Tasmaniamentioning

confidence: 99%

Section: Relict Periglacial Landforms Of East and South-east Tasmaniamentioning

confidence: 99%

Section: Introduction To Landforms Of Periglacial Originmentioning

confidence: 99%

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The distribution and paleoclimate implications of periglacial landforms in eastern Australia

Slee¹

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Restoring landscape burning is compatible with conservation and livestock production in a southeast Australian grassland fragment

French,

Prior,

Johnson

et al. 2024

Ecol Sol and Evidence

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Lowland grassland fragments in southeast Australia are valued for both sheep grazing and conservation. Many fragments are now rarely burnt, despite being shaped by millennia of Aboriginal fire‐use. Restoring fire could potentially reduce fuels, control exotic plant species, promote native species and renew Aboriginal cultural burning. However, this requires understanding of how fire and large herbivores, both native and exotic, are coupled and influence vegetation. We implemented a single round of low‐intensity experimental burns in an area of remnant grassland and patchy eucalypt woodlands in Tasmania that is managed for conservation, albeit intermittently grazed by sheep, as well as by native and exotic wild herbivores. We compared herbivore activity between burnt and unburnt areas over 2 years using cameras and scat transects, and assessed how fire and herbivory influenced herbaceous biomass and the cover of broad vegetation classes with and without herbivore exclusion. Contrary to expectations, burnt areas did not disproportionately attract the main herbivores: domestic sheep, introduced deer and native wallabies. In the predominant grassy sward, grazing and fire both reduced herbaceous biomass but we found no support for our hypothesis that grazing reduces biomass more strongly after burning. This contrasts with isolated patches of Poa tussock grassland, where fire reduced biomass much more strongly than grazing, and grazing effects on biomass were more pronounced following burning. The cover of broad vegetation classes was little affected by burning, but excluding herbivores increased exotic grass cover in both burnt and unburnt plots. Practical implication. In degraded fragments of lowland native grassland, burning and grazing do not necessarily act as strongly synergistic disturbances. Grazing by sheep and wild herbivores can help to control exotic grasses and reduce herbaceous biomass, although burning is much more effective than grazing for reducing biomass of unpalatable Poa tussock grassland. Our results suggest that returning occasional low‐intensity fires to our study system, and other degraded grassland‐woodland fragments, can be compatible with livestock production and conservation goals, but this requires caution and adaptive management.

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The distribution and climatic implications of periglacial landforms in eastern Australia

Slee

Shulmeister

2015

J Quaternary Science

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Mapping of over 4000 block deposits and scree slopes in eastern Australia is used to determine the extent of past strong freeze-thaw activity. Freeze-thaw landforms are common in the high country as far north as 30˚S. There is a clear association between the locations of relict periglacial landforms and areas that receive more than 50 modern frost days. We infer about 10.5˚C cooling north of 35˚S in the Diving Range, about 9˚C in the Australian Alps and about 5˚C in Tasmania during the phases when the lowest block deposits were active. An unexpected observation is the importance of precipitation in the distribution of block deposits north of 35˚S. Here, the majority of block deposits have a southerly or westerly aspect, and lie in a narrow modern precipitation band of ca. 900-1050 mm. To the east, high-elevation areas appear to have weaker diurnal oscillations limiting freezethaw activity. To the west, block deposits are absent, probably due to insufficient moisture to drive freeze-thaw processes. We cannot define specific last glaciation precipitation but the maintenance of a strong east-west precipitation gradient during glacial times is consistent with the maintenance of onshore easterlies during cold periods.

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

Cited by 26 publications

References 46 publications

The distribution and paleoclimate implications of periglacial landforms in eastern Australia

The distribution and paleoclimate implications of periglacial landforms in eastern Australia

Restoring landscape burning is compatible with conservation and livestock production in a southeast Australian grassland fragment

The distribution and climatic implications of periglacial landforms in eastern Australia

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