A colossal impactor reshaped Mars’ terrain about 2.3 million years ago, not only creating a massive crater but also scattering 2 billion smaller craters across the Red Planet, recent research reveals.
The primary crater, dubbed Corinto, spans approximately 8.7 miles (14 kilometers) and sits within Elysium Planitia—a vast plain near Mars’ equator. The frequency of asteroids large enough to leave such an indelible mark is rare, occurring roughly every 3 million years, suggesting Corinto could be the youngest crater of its magnitude on Mars, as unveiled at the 55th annual Lunar and Planetary Science Conference in Texas.
“Corinto represents a newly formed impact crater within Elysium Planitia, generating one of Mars’ most extensive networks of secondary craters,” researchers shared in a study presented at the conference. The investigation into Corinto and its surrounding area was made possible through data from the High Resolution Imaging Experiment (HiRISE) and the Context Camera (CTX) aboard the Mars Reconnaissance Orbiter (MRO).
The impact that birthed Corinto also peppered the landscape with smaller craters. These fragments, breaking off and radiating outward, have left patterns still discernible today. The secondary craters, primarily found to the south and southwest of Corinto, have some ejecta landing as far as 1,150 miles (1,850 km) from the main site.
Researchers have categorized these secondary craters into four groups based on their shape and proximity to Corinto. The closest, Facies 0 craters, are semi-circular, while the most distant, Facies 3 craters, appear long and narrow.
The study notes variations in the appearance of these craters with distance from Corinto, likely due to differences in impact velocity and the size of the ejected material. The trajectory of the fragments and the slightly elliptical shape of Corinto suggest the impacting object approached from the north at a shallow angle between 30 to 45 degrees, composed of robust basalt.
Interestingly, Corinto’s interior, lying 0.6 mile (1 km) beneath the Martian surface, is pockmarked with numerous pits. These features, all smaller than 660 feet (200 meters) in diameter, hint at a past where water ice covered the area. The pits likely formed from intense degassing when the water ice was superheated by the impact.
This groundbreaking study awaits publication in a peer-reviewed journal, offering new insights into the dynamic processes shaping Mars’ surface.