The conventional wisdom regarding the genesis of our planet has been turned on its head by a new study from Curtin University that suggests the early continents of Earth were formed as a result of comet impacts as our Solar System entered and exited the spiral arms of the Milky Way Galaxy.
A new perspective on Earth’s early history and our place in the universe is provided by the new research, which was published in Geology and challenges the conventional wisdom that the planet’s crust was only created by internal processes.
Studying minerals in the Earth’s crust revealed a rhythm of crust production every 200 million years or so, Professor Chris Kirkland, the study’s principal investigator, from Curtin’s School of Earth and Planetary Sciences, said. This rhythm matched our Solar System’s transit through regions 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.”
Our study reveals an exciting link between geological processes on Earth and the movement of the Solar System in our galaxy. 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 Chris Kirkland
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.
