NASA has published a series of images taken by the LRO spacecraft orbiting the Moon. They show a frozen lava flow in Mare Crisium.
Clearly defined lava flows are rarely observed on the Moon. Most lunar lava erupted onto the surface in the form of low-viscosity basalts with shallow flow edges. Over time, they deteriorated and became indistinguishable due to the formation of regolith.
However, the flow photographed by LRO differs from them. It is located at the eastern edge of Mare Crisium and has clearly defined edges and steep sides. This indicates that it has a higher viscosity than typical lunar basalts, which can be explained either by its chemical composition or by the conditions of the eruption.
The stream flows along the eastern edge of Mare Crisium in rugged terrain with highlands rising 1.4 km above the surrounding plains. Most likely, its source is located near the border of the highlands. Perhaps it is a shallow depression near the source of the flow, or perhaps the crater was buried under a layer of regolith that had “flowed” down from the highlands.
The flow photographed by LRO covers an area of approximately 15 km² and has a volume of approximately 1.5 km³. It is 7 km long, and its width decreases from 4.1 km in the highlands to approximately 1.4 km at the northern end. At the border with the highlands, the thickness of the flow is about 200 meters, and at the northern end it is already 100 meters. The upper part of the flow has a convex shape in the cross section; the flow has no central channel or surrounding ridges.
As a rule, lava flows form in several stages — and this one is no exception. Approximately halfway along its length, its thickness decreases sharply by about 20 meters. In addition, the northern part of the flow is significantly more cratered than the southern part (the older the surface, the more craters there are). Most likely, many craters in the northern part are secondary, formed as a result of falling onto the lunar surface during the formation of larger craters.
Just a reminder that in March this year, Mare Crisium became the landing site for Firefly Aerospace’s Blue Ghost spacecraft. To date, this is the only private lunar mission that has successfully completed all of its assigned tasks.
According to LROC
