Glacial and sedimentary systems 
 

A major activity within the CcASH project is the application of surface exposure dating with cosmogenic radionuclides to study glacial and sedimentary systems.

Scientists at Sickle Nunatak, North Victoria Land, Antarctica

Surface exposure dating uses the cosmogenic radionuclides (CRNs), ¹⁰Be, ²⁶Al and ³⁶Cl, produced in-situ at the Earth's surface in exposed bedrock, glacially transported boulders and sediments. The application of CRNs in the Earth sciences (geology, oceanography, geomorphology, etc.) has provided the essential geochronological timing of continental and polar glacial history over the past few millions years, and revolutionised our understanding of the processes controlling landscape evolution on spatial scales of metres to kilometres.

Using this innovative technique, researchers are able to date when glaciers in the past reached their maximum size, and hence address fundamental questions regarding the synchronicity (or otherwise) and comparative magnitude of millennial-scale glacial cycles between the Northern and Southern Hemispheres.

They are also able to measure  the volume  and retreat rate of the great ice sheets at the Last Glacial maximum about 20,000 years ago, and the processes by which glaciations shape our landscape.

Researchers can measure how fast bedrock erodes, the rate at which soil is formed, sediment generation rates, and address questions relating to processes driving landscape modification. Hence, they can now measure the age of landforms and the rate at which they change.

Research themes in glacial chronology
  

Exposure age dating is applied to Southern Hemisphere glacial systems, such as in Irian Jaya, Tasmania and New Zealand, to document the extent and timing of Southern Hemisphere continental glacial systems. This research challenges the paradigm of globally synchronised millennial-scale abrupt climate changes across Earth's hemispheres. Similarly, debate centres on the timing of glacial cycles on the Tibetan Plateau of Central Asia and whether global or regional climate signals are evident in these records.

Studies in Antarctica provide new information on the evolution of the East Antarctic Ice Sheet over the past two million years, and its youngest phase of retreat and thinning during the Last Glacial Maximum.

Research themes in landscape evolution
 

Measurement of cosmogenic nuclides in buried materials, surface sediments, depth profiles and exposed bedrock are elucidating the complex geomorphology of Australia's ancient and arid landforms, such as dunefields, desert gibbers and granite coastal escarpments. These activities allow scientists to determine differences in regional erosion rates across the Australian continent as a function of tectonic or climatic influences, basin wide and river sediment budgets and escarpment retreat rates.

Radiocarbon and cosmogenic ¹⁰Be in marine cores from equatorial Pacific Ocean (Peru), New Zealand and the Southern Ocean, and also from Antarctic coastal ice cores are being used to study atmospheric fallout, sedimentation rates and ENSO-type climate modes over the last 20,000 years since the Last Glacial Maximum (LGM).

Specific studies
 

Within this group are a number of specific studies, including:

> The last deglaciation in New Zealand; 20,000 to 10,000 years ago
> Tasmania's glacial history over the past one million years
> Nunatak dipsticks and stability of the East Antarctic Ice Sheet
> Drainage of West Antarctic ice sheet into the Ross Ice Shelf
> The timing and size of Younger Dryas glaciation in Ireland, 12,000 years ago
> Equatorial glacial change at Mt Trikora, New Guinea
> Sub glacial bedrock from the base of the Birkner Island ice core, West Antarctica
> Exposure dating at Lambert Glacier, Northern Prince Charles Mountains Antarctica
> Neotectonic fault movement and natural landslides in Hong Kong
> Soil production rates in heath and forests of the Blue Mountains, NSW, Australia
> Soil production rates in semi-arid environments, Northern Territory, Australia
> Influence of climate, tectonics and lithology as forcing factors in landscape change
> Erosion rates, glacial chronologies and paleo-hydrology in the high altitude arid Tibetan landscape
> Coastal cliff-top platforms and boulders, eastern Australia
> Exposure and burial histories of Australian Stony Desert gibbers and quartz cobbles
> Paleo-hydrology of the Dead Sea Rift and dating desert stone-pavements
> Marine cores from the Peruvian continental margin and paleo ENSO variabiliy over the past 20,000 years
> ODP core MD-67, Eastern Indian Ocean and Earth's magnetic field intensity over the past 45,000 years.