Australia's geological links to North America
07 August 2012
Australia's links with Canada may go back a little further than those created by the British Empire and Captain Cook's expertise as a cartographer – in fact recent research suggests geological ties actually go back at least 1655 million years. Parts of the story also provide clues to the origins of Australia’s mineral wealth.
Research undertaken by Geoscience Australia scientists indicate that the Australian continent was once geologically linked with parts of present day North America, when they were all were part of an ancient supercontinent called Nuna.
Speaking at the International Geological Congress in Brisbane today, Dr David Huston said that recent acquisition of deep seismic reflection and geochronological data has allowed scientists to establish the location of crustal boundaries within the Australian continent, as well as the timing of their formation and related tectonic movement.
Dr Huston’s investigations indicate that most mineral deposits in the richly-mineralised North Australian Craton formed during the amalgamation and subsequent break-up of Nuna. Cratons are old, stable and relatively undisturbed continental cores which make up the primary building blocks of continents onto which younger rocks accumulate.
Nuna, or Columbia, is thought to have existed approximately 1800 to 1500 million years ago in the Paleoproterozoic Era which was made up of the former continents of Laurentia and Baltica as well as Amazonia, Australia and possibly Siberia, North China and Kalaharia.
Research by fellow Geoscience Australia geologist Alex Lambeck found that analysis of some Australian sediment samples were not derived from rocks found within Australia, but possibly from Laurentia. Today, Laurentia makes up much of modern North America, including the south western and central United States and central and eastern Canada, and extends into Greenland. This suggests the North Australian Craton was linked to Laurentia when it and Baltica were part of the supercontinent Nuna.
Commenting on the research, the Chief of Geoscience Australia’s Minerals and Natural Hazards Division, Dr Andrew Barnicoat, said the work by both scientists would help to develop a greater understanding of the Australian continent and its development.
"It is through this type of groundbreaking research that Geoscience Australia is able to develop an improved perspective of the geology at depth and its relationship with surface geology. This, in turn, provides the minerals exploration industry with well considered, pre-competitive data to assist with the search for world class mineral deposits and energy sources," Dr Barnicoat said.
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