A massive hole measuring 315 miles across in the bedrock beneath East Antarctica’s ice sheet has been identified as an impact crater likely caused by a meteorite. Researchers have proposed various explanations for its existence, but the latest evidence suggests this enormous crater is indeed a product of a cataclysmic event. Located at 70°S 120°E, it is believed to be the greatest known impact crater on Earth in terms of size.
The Wilkes Land crater sits about 1 mile beneath the surface and was first detected as a huge dent in Earth’s gravitational field. Newer techniques have revealed that it is likely more than double its initial estimated size. Initial surveys indicated a diameter of around 150 miles, but satellite remote sensing techniques used in a 2018 study showed the crater to be much larger.
Researchers have proposed several explanations for the crater, including volcanic structures, sedimentary basins, and deeply eroded valleys. However, the central peak is likely a “mascon” or a structure formed by the meteor crashing through Earth’s crust and affecting the mantle beneath. This mass concentration would result in a positive gravity anomaly.
The crater’s U-shape is not perfectly circular due to tectonic processes that ripped Australia and Antarctica apart. Parts of the crater are visible in southern Australia, supporting the conclusion that it was caused by a meteor impact. If confirmed, this crater “would be the greatest impact crater known” on Earth in terms of size.
Source: https://www.livescience.com/planet-earth/antarctica/wilkes-land-crater-the-giant-hole-in-east-antarcticas-gravitational-field-likely-caused-by-a-meteorite