The surfaces of the Moon, Mars, Mercury and many other bodies in the solar system are densely dotted with impact craters, indicating their numerous collisions with asteroids and comets. Our planet is no exception. Over the past 4.5 billion years, it has experienced many powerful impacts. It's just that tectonics and erosion have erased almost all cosmic scars from the earth's surface.
Many impact structures of the Earth were discovered by accident - during high-altitude surveys, while drilling wells or studying gravity maps. For example, the famous Chicxolub crater, which is usually associated with the extinction of dinosaurs, was discovered only in 1978 when conducting geophysical studies at the bottom of the Gulf of Mexico. However, it took several more years before its existence was finally proven.
In 1991, geologist Michael Rampino, inspired by the discovery of Chiksolub, decided to study Earth's gravity maps in order to find traces of other craters. His work was crowned with success. To the west of the Falkland Islands, Rampino found a gravitational anomaly very similar to that at Chixolub. She testified that in the south of the Atlantic, a 250-kilometer crater was buried under thick layers of sedimentary deposits. Rampino published an article about his find, but due to his lack of other evidence, it did not attract much attention.
Falklands from space
Many years later, Rampino's article caught the eye of Max Rocca, a crater hunter from Argentina who is credited with finding traces of a 50 km shock formation in Colombia. In 2015, Rocca received from Paraguayan scientist Jaime Báez Presser a magnetic map of the area of the alleged Falklands crater and found traces of the same positive magnetic anomaly as at Chicxolub crater. It is believed that it arose due to the magnetization of the rock molten by the impact.
Gravity anomalies at the site of Chicxolub Crater (left) and the alleged Falkland Crater (right)
Rocca then retrieved seismic data from this part of the Atlantic by the oil company Schlumberger. They also point to traces of an ancient shock structure. As a result, Rocca, Rampino and Presser wrote a joint article which has already been accepted for publication by Terra Nova magazine.
But, although the data of the researchers looks quite intriguing, they are unlikely to be enough to remove all doubts about the crater. To finally prove its existence, it is necessary to drill the seabed and extract rock samples. Scientists hope that the publication will generate sufficient interest to fund such an expedition.
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Magnetic anomaly near the Falklands
With regard to the age of the potential crater, Rocca and Rampino are cautiously suggesting that its formation may be related to the great Permian extinction. This largest catastrophe in the history of the earth's biosphere occurred 252 million years ago. During the extinction, 96% of all marine species, 73% of all terrestrial vertebrate species, about 57% of genera and 83% of insects disappeared. Most scientists associate the Permian extinction with an increase in volcanic activity, but there are other versions, including the collision of the Earth with a large asteroid.