Bob Zimmerman reports on a new scientific paper that describes a type of pit seen on the Mars surface that looks very similar to cave openings on earth: Finding caves on Mars -Behind The Black.

Bob notes that a cluster of such pits are in area where there could be significant water ice deposits. If the pits lead into extended lava tube caves, these could be used as shelter by future settlers and the water would be a key resource for them as well. He explains why lava tubes could be more common on Mars than on earth.

Here is the paper: Atypical pit craters on Mars: New insights from THEMIS, CTX, and HiRISE observations – Cushing – 2015 – Journal of Geophysical Research: Planets.