Watching asteroids: oldest find in Australia (Introduction)

by David Turell , Sunday, March 09, 2025, 19:58 (5 days ago) @ David Turell

A hit crater 3.5 million years old:

https://www.sciencedaily.com/releases/2025/03/250306122924.htm

"The team from Curtin's School of Earth and Planetary Sciences and the Geological Survey of Western Australia (GSWA) investigated rock layers in the North Pole Dome -- an area of the Pilbara region of Western Australia -- and found evidence of a major meteorite impact 3.5 billion years ago.

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"'Before our discovery, the oldest impact crater was 2.2 billion years old, so this is by far the oldest known crater ever found on Earth," Professor Johnson said.

"Researchers discovered the crater thanks to 'shatter cones', distinctive rock formations only formed under the intense pressure of a meteorite strike.

"The shatter cones at the site, about 40 kilometres west of Marble Bar in WA's Pilbara region, were formed when a meteorite slammed into the area at more than 36,000km/h.

"This would have been a major planetary event, resulting in a crater more than 100km wide that would have sent debris flying across the globe.

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"Until now, the absence of any truly ancient craters means they are largely ignored by geologists.

"'This study provides a crucial piece of the puzzle of Earth's impact history and suggests there may be many other ancient craters that could be discovered over time."

"Co-lead author Professor Chris Kirkland, also from Curtin's School of Earth and Planetary Sciences, said the discovery shed new light on how meteorites shaped Earth's early environment.

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"'It...radically refines our understanding of crust formation: the tremendous amount of energy from this impact could have played a role in shaping early Earth's crust by pushing one part of the Earth's crust under another, or by forcing magma to rise from deep within the Earth's mantle toward the surface.

"'It may have even contributed to the formation of cratons, which are large, stable landmasses that became the foundation of continents.'"

Comment: Compare this 67 mile-wide crater to Chixculub at ten miles-wide. Then note that life was just in beginning stages at this point in time. And survived!!