The Moon Guide
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U. S. N. O.
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The phase of the Moon right now

Phase
 
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 Wrinkle ridges
Wrinkle ridges in
Oceanus Procellarum
< Ray craters
Ageing wrinkles
Like us, the Moon also has wrinkles, in the form of “wrinkle ridges”, low sinuous ridges formed on the maria that can extend for several hundred kilometres. They are most likely formed when the part of the Moon’s surface was compressed as the mare lava cooled and contracted as it sunk into the interior of the basin, scrunching up at the surface and buckling into ridges.

Volcanic domes
Volcanic domes are small swellings of relatively low relief, typically found in or near the maria. They have summit pit features like some volcanoes on the Earth, and are formed from a much stickier lava than that responsible for the mare. Marius Hills, located in Oceanus Procellarum, is the largest group of volcanic cones and domes on the Moon; over one hundred domes are surrounded by twenty or so long sinuous lava channels.

We all have faults
Alpine Valley
The Alpine Valley
Evidence for faulting appears all over the lunar surface. A fault is a rock fracture which shows evidence of movement compared to surrounding rock surfaces. They are usually a result of differential motion of two rock faces, and are usually the locations for earthquakes on Earth. On the Moon, one particularly prominent fault feature is the 180 kilometre long Alpine Valley, which connects Mare Imbrium to Mare Frigoris. The sequence of events here probably began with a set of two parallel faults that cut right across the mountain range as a result of crustal tension. Further tension probably forced the area bounded by the faults to sink down considerably below the level of the mountain tops. Then, the valley floor was flooded with lavas which flowed from the maria. Finally, a smaller rille appeared in the centre, again due to tension.
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Lunar geologist

Lunar geology

Moon rocks on Earth

Moon quakes

How the Moon was formed

Geology of the Moon's features

What is the Moon made of?

Lunar gardening

About impacts

Ray craters

Ageing wrinkles

Meandering channels

 
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