Click for original image.

Cool image time! The picture to the right, rotated, cropped, and reduced to post here, was taken on January 25, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It was taken not as part of any specific research project, but to fill a gap in MRO’s picture-taking schedule in order to maintain the camera’s temperature. When such pictures need to be taken, the camera team tries to find something of interest in the area to be shot. Sometimes the picture is boring. Sometimes fascinating. Today’s picture I think falls into the latter category.

This is a lava flood plain, as shown in the overview map below. The meandering ridges are likely what geologists call lava dikes, places where lava was extruded out through a fissure. This suggests that the flat flood lava was an older crust, and that there was hot molten lava below it that eventually pushed its way up through cracks in that crust.

This hypothesis however is not certain, as the meandering nature of the ridges does not correspond well with what one would expect from such crustal cracks.

The white dot in the southern part of Amazonis Planitia marks this location, about 1,000 miles to the southwest of the caldera of Mars’ largest volcano, Olympus Mons.

Did this lava come from Olympus? No one yet knows but it is not likely. I call the region between Olympus and Elysium Mons volcano country, because almost everything on the surface here is either flood lava (such as the Athabasca Valles flood lava), or volcanic ash (the Medusa Fossae Formation). Amazonis Planitia itself is almost entirely covered by flood lava. Orbital data has identified evidence of many different eruptions and flood lava events, but that data is insufficient to as yet pin this lava to any particular event.

Note also that there is also practically no evidence of near surface ice here, as this region is in Mars’ very dry equatorial tropics.