NASA’s Perseverance rover has detected substantial rock deposits along the outer rim of Jezero Crater, which planetary scientists believe were formed by a series of impacts with large celestial bodies. This geological feature, designated Broom Point, measures 75 meters in thickness and is estimated to be over 3.9 billion years old, making it one of the oldest formations on the Red Planet.
The scientific findings, published in the Journal of Geophysical Research: Planets, shed light on a period of intense meteorite bombardment in early Martian history. After ascending the western edge of the crater in late 2024, the rover began exploring regions beyond Jezero. Unlike Earth, where tectonic processes have reshaped most of the ancient crust, Mars lacks such mechanisms, allowing its rocks to retain their original structure and offering a glimpse into eras that have not survived on our planet.
In the Broom Point area, researchers have identified six types of rock formations, dominated by breccias—composite materials made of angular fragments interspersed with fine-grained layers. Characteristic cavities from gas release and dark glassy spheres found within these layers indicate that the material was melted by extreme temperatures during impacts. The largest of these spheres are comparable to those discovered in deposits from the Chicxulub asteroid impact on Earth.
The study’s authors explain that the alternating layers reflect collisions of varying intensity: debris from both distant and nearby impacts settled in this region, while some layers resemble evidence of debris flows, suggesting possible interaction between molten material and water or ice.
The Perseverance team has already collected core samples named “Bell Island” and “Main River”; their laboratory dating on Earth in the future will help refine the bombardment timeline and improve understanding of similar processes on the early Earth.
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