A mysterious area of layered bedrock on Mars was formed by a volcanic explosion on the red planet, research shows. "Spirit," one of NASA's two Mars Exploration Rovers, mapped the tabletop-like geologic formation, which scientists call "Home Plate" because of its shape resembling a home plate used in baseball.

The analysis shows that the outcrop's layered debris probably resulted from a volcanic explosion, in which larger grains fell first and were buried under finer materials and later rearranged by wind. The findings were reported in the journal Science.