From Curtin University (AU): “Comet impacts formed continents when Solar System entered galactic arms”

From Curtin University (AU)

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New Curtin research has found evidence that Earth’s early continents resulted from being hit by comets as our Solar System passed into and out of the spiral arms of the Milky Way Galaxy, turning traditional thinking about our planet’s formation on its head.

Milky Way taken from Australia.

The new research, published in Geology [below], challenges the existing theory that Earth’s crust was solely formed by processes inside our planet, casting a new light on the formative history of Earth and our place in the cosmos.

Lead researcher Professor Chris Kirkland, from the Timescales of Mineral Systems Group within Curtin’s School of Earth and Planetary Sciences, said studying minerals in the Earth’s crust revealed a rhythm of crust production every 200 million years or so that matched our Solar System’s transit through areas of the galaxy with a higher density of stars.

“The Solar System orbits around the Milky Way, passing between the spiral arms of the galaxy approximately every 200 million years,” Professor Kirkland said.

“From looking at the age and isotopic signature of minerals from both the Pilbara Craton in Western Australia and North Atlantic Craton in Greenland, we see a similar rhythm of crust production, which coincides with periods during which the Solar System journeyed through areas of the galaxy most heavily populated by stars.”

“When passing through regions of higher star density, comets would have been dislodged from the most distant reaches of the Solar System, some of which impacted Earth.

“Increased comet impact on Earth would have led to greater melting of the Earth’s surface to produce the buoyant nuclei of the early continents.”

Professor Kirkland said the findings challenged the existing theory that crust production was entirely related to processes internal to the Earth.

“Our study reveals an exciting link between geological processes on Earth and the movement of the Solar System in our galaxy,” Professor Kirkland said.

“Linking the formation of continents, the landmasses on which we all live and where we find the majority of our mineral resources, to the passage of the Solar System through the Milky Way casts a whole new light on the formative history of our planet and its place in the cosmos.”

Professor Kirkland is affiliated with The Institute for Geoscience Research (TIGeR), Curtin’s flagship Earth Sciences research institute.

Also contributing to the study were researchers from the University of Lincoln, the Astromaterials Research and Exploration Science Division within NASA’s Johnson Space Center and the Geological Survey of Western Australia.

Science paper:

See the full article here .


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Curtin University (AU) is an Australian public research university based in Bentley and Perth, Western Australia. The university is named after the 14th Prime Minister of Australia, John Curtin, and is the largest university in Western Australia, with over 58,000 students (as of 2016).

Curtin would like to pay respect to the indigenous members of our community by acknowledging the traditional owners of the land on which the Perth campus is located, the Wadjuk people of the Nyungar Nation; and on our Kalgoorlie campus, the Wongutha people of the North-Eastern Goldfields.

Curtin was conferred university status after legislation was passed by the Parliament of Western Australia in 1986. Since then, the university has been expanding its presence and has campuses in Singapore, Malaysia, Dubai and Mauritius. It has ties with 90 exchange universities in 20 countries. The University comprises five main faculties with over 95 specialists centres. The University formerly had a Sydney campus between 2005 & 2016. On 17 September 2015, Curtin University Council made a decision to close its Sydney campus by early 2017.

Curtin University is a member of Australian Technology Network (ATN), and is active in research in a range of academic and practical fields, including Resources and Energy (e.g., petroleum gas), Information and Communication, Health, Ageing and Well-being (Public Health), Communities and Changing Environments, Growth and Prosperity and Creative Writing.

It is the only Western Australian university to produce a PhD recipient of the AINSE gold medal, which is the highest recognition for PhD-level research excellence in Australia and New Zealand.

Curtin has become active in research and partnerships overseas, particularly in mainland China. It is involved in a number of business, management, and research projects, particularly in supercomputing, where the university participates in a tri-continental array with nodes in Perth, Beijing, and Edinburgh. Western Australia has become an important exporter of minerals, petroleum and natural gas. The Chinese Premier Wen Jiabao visited the Woodside-funded hydrocarbon research facility during his visit to Australia in 2005.