A single large impact crater on Mars created about 1 billion other smaller craters at distances of up to almost 1,900 kilometers, caused by the ejecta of material.
A study published at the LV Annual Lunar and Planetary Science Conference in Texas focuses on a crater called Corinth. It is located in Elysium Planitia, just 17 degrees north of the Red Planet’s equator. It is a relatively young crater by Martian standards, and scientists’ best estimate of its age is about 2.34 million years ago. However, it is quite massive for being so young, as the average time between impacts of its size is around 3 million years. Therefore, scientists believe it could be the newest crater of its size on Mars.
The interest in the Corinth crater lies in the fact that it has an extensive “ray system.” That means a significant amount of ejecta was ejected from the impact site and landed on other parts of the planet, creating “rays” from the central impact point that can still be seen today on a map of the planet’s surface, Universe Today reports. .
The Corinto crater is about 14 km in diameter and 1 km deep. Its inner basin is filled with other smaller craters that were produced after the impact. Indications suggest that it was filled with water ice when it was hit, as there appeared to be some outgassing of the superheated ice after impact. Calculations point to a relatively steep impact angle, about 30 to 45 degrees, and the impactor appeared to come from the north.
As a result, much of the ejecta’s impact field lies to the south, especially southwest, of the crater. While some secondary ejecta craters are located north of the main one, it seems clear that the angle of the impactor was significant enough to push most of the ejecta craters to the south.
Following the trajectory of this ejecta a few million years later is not easy. The scientists, led by Matthew Golombeck of JPL (Jet Propulsion Laboratory) used data collected by HiRISE and the Mars Reconnaissance Orbiter (MRO) Context Camera (CTX) and analyzed the characteristics of smaller craters surrounding the main crater Corinth. In particular, they looked for craters that appeared to have been caused by ejecta rather than an interplanetary impactor.
They grouped the different types of ejecta craters they found into five different “facies,” focusing mainly on how far they were from the main crater. Each facies has its distinct characteristics. For example, Facies 0, the closest to the main crater, is semicircular, does not appear to have ejecta, or has very distinct rims. On the other hand, Facies 3 craters are long and narrow rather than semicircular (suggesting that something rolled to create them) and have appeared very bright in MRO images.
As a result, scientists discovered that there are about 1 billion secondary impact craters larger than 10 meters caused by the Corinthian ejecta. And these secondary craters appear up to 1,850 km away. That would make it by far the most ‘shocking’ of recent Martian craters in terms of the sheer number and distance of its ejecta.
