Saturday, June 13, 2009

Subsurface of Lunar Seas Layered

The substructure of a lunar mare comprised of layers of basalt
and regolith. The arrows indicate the reflection of radio waves.

Ridges in a lunar mare and a reflection surface in the subsurface.
The red arcs indicate the location of ridges. The locations of the
deformed parts of the layers and ridges coincide.

"The fact that the basalt and regolith layers are in parallel shows that the ridge formation occurred after the basalt was deposited on the surface. In other words, scientists speculate that lunar ridges are topographic wrinkles created by diastrophism, which happened when the entire globe contracted as it cooled. Prior to this discovery by KAGUYA, the ridges were believed to have been caused by the weight of the piled basalt layer. The ridge formation occurred less than 2.8 billion years ago, suggesting that the impact of the cooling was rapid and significant."

Read the JAXA feature story HERE.