Mars Craters Show A Break From Asteroid Impacts

[Buster's Uncle]

Mars Craters Show A Break From Asteroid Impacts
International Business Times
Elana Glowatz  April 25, 2017



Mars was bombarded with asteroids and other objects during its youth, carving out craters from its surface, but at least it got a little breather of 400 million years.

Researchers say there weren’t any large impacts on Mars during that lull, and it lines up with the histories of the rest of the inner solar system. A study in the journal Nature Geoscience estimates the quiet period to have happened 4.1 billion to 4.4 billion years ago — compared to Mars’ age of about 4.5 billion years — and separated the planet’s early bombardment from another series referred to as the late heavy bombardment.

Scientists from the Southwest Research Institute and the University of Arizona studied large basins on Mars, including the most ancient among them, the 6,000-mile-wide Borealis. Comparing their analysis to the known ages of those basins, they determined no other features on Mars caused by large impacts could have formed during the lull.



Mars has experienced large collisions during its history, including the one that created the Borealis basin at the top of the planet close to the beginning of its life. Photo: University of Arizona/LPL/Southwest Research Institute


Part of the aging information about Borealis came from “impact fragments from Mars that ultimately arrived on Earth,” said Bill Bottke, the study’s lead author.

“The new results reveal that Mars’ impact history closely parallels the bombardment histories we’ve inferred for the Moon, the asteroid belt, and the planet Mercury,” Bottke said in a statement from the Southwest Research Institute. “The lull itself is an important period in the evolution of Mars and other planets.”


https://www.yahoo.com/news/mars-craters-show-break-asteroid-195310806.html