Scientists Discover Giant Asteroid Impact Crater in Australia, the Largest Ever Recorded on Earth

KOMPAS.com – Scientists have discovered a giant structure that may have been an asteroid impact crater hundreds of millions of years ago, hidden beneath Australian soil.

If confirmed, the find buried at Deniliquin, New South Wales will be the largest asteroid impact crater ever recorded on Earth.

Quoted from Live Science, Tuesday (15/8/2023), this giant structure has a diameter of up to 520 kilometers.

That size exceeds that of Vredefort, the largest impact crater located in South Africa with a diameter of nearly 300 kilometers.

However, the research in the Tectonophysics journal still has to be further tested by drilling.

Also read: Scientists Discover Hidden Underworld Full of Strange Creatures

Earth’s hidden early history

Geologist and researcher at Geoscience Australia, Andrew Glickson explains, the history of “bombing” Earth by asteroids has been largely hidden.

This is due to several factors, such as erosion, the process by which gravity, wind and water slowly erode land material over time.

When it hits Earth, the asteroid will create a crater with an uplifted core. This condition is similar to a drop of water splashing up when someone drops a pebble into a pond.

The raised section is a key characteristic of a large impact structure.

However, these characteristics can be eroded over thousands to millions of years, making the structures difficult to identify.

Structures can also be buried by sediment over time or lost by subduction.

Subduction itself can make tectonic plates collide with each other and slide down, into the layers of the Earth’s mantle.

However, new geophysical findings suggest that the signatures of the asteroid-formed impact structures may be tens of kilometers in diameter.

This also marks a paradigm shift in the understanding of how the Earth has evolved over thousands of years.

“This includes the pioneering discovery of an impact ‘ejecta’, a material or materials ejected from a crater upon impact,” Glickson said.

Also read: The Asteroid That Destroyed the Dinosaurs 66 Million Years Ago Triggered a Giant Tsunami

Maybe trigger a mass extinction

The researchers suspect that the oldest layers of ejecta were found in early land sediments, and could mark the end of a large meteor shower that hit Earth.

According to recent evidence, Earth and other planets in the solar system experienced intense meteor showers hundreds of millions of years ago.

A number of major impacts of the fall of these celestial bodies are also associated with mass extinction events on the surface of the Earth.

Reporting from the Business Insider page, Tuesday, Glickson said, scientists have difficulty knowing exactly when the giant asteroid hit before drilling.

However, he believes, the incident occurred when Australia was still part of Gondwana, a large continent that is currently developing into South America, Africa, Arabia, Madagascar, India and Antarctica.

This means that the incident of a large asteroid collision occurred at least 180 million years ago or more.

“In particular, I think it may have triggered what’s called the Hirnantian glaciation (ice age) stage, which lasted between 445.2 and 443.8 million years ago,” Glickson said.

Also read: What’s the Difference between Meteors, Asteroids and Comets? Here’s the explanation

The Hirnantian is the last stage of the Ordovician, the second period of the Paleozoic Era, a time when Earth’s landmass was still fluid.

The Hirnantian Period was marked by cold temperatures, major glaciation and a severe drop in sea level.

At the end of this era, temperatures slowly rose, glaciers melted, and sea levels returned to the same or slightly higher levels than before the glaciation.

The Hirnantian mass extinction itself was caused by ice, which wiped out 85 percent of the planet’s species, some 350 million years before the dinosaurs died out.

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2023-08-16 03:30:00
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