Rilles and Wrinkle Ridges

Describe the nature of rilles and wrinkle ridges

Rilles are cracks or clefts on the lunar surface notably near maria. They are geological faults caused by collapsed lava tubes. When lava flowed on the Moon, the top and sides of these tubes solidified first while lava flowed underneath. When this lava moved away or solidified, the top or roof of the tube collapsed, leaving these rilles.

Wrinkle ridges are ridges of maria, usually hundreds of kilometres in length. They are not considered mountains, being only around 200 metres high.

These are thought to have been lava tunnels that contracted and cooled.


Images New Window

Ariadaeus Rille

Links New Window

Astronomy Picture of the day Rilles

Department of Geological Sciences Volcanism & Rilles on the Moon

Starry Skies 3-D Wrinkle Ridges

Moonwatch Winkle ridges


What is a rille?
What is a wrinkle ridge? What do they look like? How were they formed?