Standing on top of moon rock one notices the same granite rocks filling the panorama.

Some covered with sand and soil but many large, smooth patches glistening in the sunlight of into the distance.

Beneath your feed and all along the trip up one notices a flaky appearance to the otherwise relatively smooth surface.

The flaking is due to differential expansion from temperature changes from day to night. These are the results of surface expansion and contraction.

Differential expansion occurs at a deeper level too.

This creates large slabs to separate from the parent rock

Each slabs thickness is dependent on the depth to which the differential movement penetrates into the rock. It can be quite consistent where the rock is fairly uniform.

Expansion and contraction forces cause some of these slabs to creep and lift one another with dramatic results.

Slabs on sloped sides slide downwards under the force of gravity.

Once slabs have slid away or otherwise broken up the newly exposed surface (reddish brown) is exposed to the sun and the process of slab formation starts again with new cracks forming.

After many repetitions of this process rock bodies that start out square are gradually rounded... this is how moon rock got its shape and you can see it happening to all the other large bodies of rock in the area.

Other posts in this series

Augrabies - The hidden river
Augrabies - The Falls and Floods
Augrabies: a "heart of stone" for valentines day.
Augrabies: Reading the geological history written on the walls
Augrabies: Lizards everywhere
Augrabies: Further examples of weathering and erosion types
Augrabies: Moon rock