Asteroid impacts have probably wiped out more species than any other type of disaster since life began on Earth. The most famous of these, the Chicxulub impactor, killed the dinosaurs about 65 million years ago and 76% of all species on the planet at the time. But this was certainly not the worst disaster; As far as we can tell, it wasn’t even the largest asteroid. This cap currently belongs to the Vredefort Crater in South Africa. With a width of more than 300 kilometers, it was the largest asteroid crater ever found, at least when it formed about 2 billion years ago. But that could change if the theory of Andrew Glickson and Tony Yates of New South Wales is correct.

They named the crater, which they estimated to be about 520 kilometers in diameter, the Deniliquin structure. Trying to study such a large structure is a difficult task, and it becomes much more difficult as the structure ages. Drs Glickson and Yates estimate the Denlikwin structure to be about 445 million years old. It takes a long time for erosion, precipitation and tectonic activity to damage any structure on Earth, no matter how large. But researchers may find some clues to the size of this impact crater.

The first is an assessment of the geophysical data of the region. Updates to these data, ending in 2020, point to a domed structure about 520 km wide from the seismic event. There is a lot of other magnetic evidence, such as “radial faults” pointing away from what is thought to be the center of the impact structure. And there are some magnetic perturbations that may have been caused by the magma returning closer to the surface after the impact.

Video of an asteroid impact that created the largest confirmed crater on Earth, though smaller than the one recently announced in New Wales. Credits: GeologyHub YouTube channel

If it exists, it must have been created to an effect of epic proportions. The authors of a new paper on the crater suggest that there was a certain time in history. Four hundred and forty-five million years ago, it coincided with a geological event called the Hirnantian glaciation stage, which was part of the first of five major extinctions at the end of the Ordovician period.

The end of the Ordovician era resulted from a massive global cooling that caused major changes in ocean chemistry and other problems. During this period, 86% of all species on Earth became extinct, as this was the second most devastating of all extinction events (after the Permian event that ended 250 million years ago).

Many geological processes can cause global cooling, but one of the most dramatic is an asteroid impact that hurled it into the upper atmosphere to block the Sun. An impact as big as creating the Denliquin structure was definitely big enough to do just that.

So could this massive crater be a clue to another asteroid causing another global catastrophe? Maybe, but to get a better timestamp of when the collision occurred, researchers would need to collect samples from deep within the impact crater’s magnetic core. There are currently no such plans, but if the theory gets enough attention, there will undoubtedly be some multi-millionaires willing to fund the attempt to explore the world’s largest impact crater – and find out if one of them is responsible. The deadliest events in world history. Source