A Journey to the Depths of Ancient Mars?

Written by Alex Jones, Ph.D. candidate at Imperial College London

Sept. 29, 2026

After spending the last six months exploring “Lac de Charmes,” a region of ancient rock beyond Jezero crater’s western rim, Perseverance has stumbled upon a vast field of light-toned rocks peppering the Martian surface.

Light-colored rocks are a strange sight on Mars, a planet dominated by dark-colored basaltic rocks. This many light-colored rocks in one place piqued the Science Team’s interest… what are they? How did they get here?

To answer the first question, Perseverance has been investigating the composition and textures of these rocks. Data so far indicates that many of them are igneous rocks called gabbro, which are dominated by minerals rich in iron and magnesium. Such rocks typically form by slow cooling and crystallization of magma deep in the crust.

So how did these deep fragments of Mars find their way to the surface?

Perseverance has spent the last week trying to answer this question by investigating a patch of possible bedrock poking out between the light-toned boulders and loose regolith.

Initial images suggest that the rock is made up of light- and dark-colored, angular fragments of rock, forming what geologists call a breccia. One possibility the team is investigating is that the light-toned boulders scattered across the hillside have eroded out of this breccia.

Breccias often form through violent processes involving the fracturing and transport of rock to produce their angular shapes. Layers of breccia observed outside Jezero have previously been attributed to asteroid impacts on early Mars. Perhaps similar impacts (or the Jezero impact itself?) could be responsible for digging up these light-colored blocks.

Only time (and of course, Perseverance), will tell.

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Full text from nasa.gov (public domain).