Careful studies of how the craters overlap other craters and other features can be used to develop a history or sequence of the bombardment on the moons and planets. Worlds with less volcanism or erosion or tectonic activity in their history will retain more impact craters since the planet formed.
Worlds with more geological or erosional activity will have newer surfaces or craters that have been so worn away as to be unrecognizable.
This assumes, of course, that the cratering rate has been fairly constant for the last few billion years.
The heavy bombardment of about 3.8 billion years ago must be taken into account when using the crater age dating technique.
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There are still small chunks of rock orbiting the Sun left over from the formation of the solar system.
At such speeds, the projecticle explodes on impact and carves out a round bowl-shaped depression on the surface. How can you distinguish an impact crater from a volcanic crater?
Volcano craters are above the surrounding area on mountaintops while the craters from impacts are below the surrounding area with raised rims.
Large craters will have a central peak formed by the rock beneath the impact point rebounding upward and they may also have terracing of the inner walls of the crater from the collapsing of the crater rim inward.
Terrestrial planets have hard surfaces that can be re-shaped by several different processes: impact cratering, volcanism, erosion, and tectonics.
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Volcanism is any eruption of molten lava onto the surface.
The molten rock has a lower density than solid rock so it rises.
The last stage of that "sweeping up", called the occurred from about 4.1 to 3.8 billion years ago.