Figure 10-8: R I V U X G
Recent Geologic Activity of Scarps This image shows a long cliff called a scarp—formed as the Moon cools, shrinks, and wrinkles—that is cutting across several small craters (see the inset, and the two arrows). Until discovery in 2010, it was thought these scarps were billions of years old. But small craters allow for a unique way to estimate ages. Small craters (less than about 400 meters) typically do not last very long on the lunar surface because they are disturbed by ongoing micrometeorite impacts. Furthermore, when an image shows that a scarp cuts across a crater, it means the scarp is even younger than the crater. By analyzing scarps and their underlying craters, some scarps are thought to be less than a billion years old, and could be as young as a hundred million years old.
Recent Geologic Activity of Scarps This image shows a long cliff called a scarp—formed as the Moon cools, shrinks, and wrinkles—that is cutting across several small craters (see the inset, and the two arrows). Until discovery in 2010, it was thought these scarps were billions of years old. But small craters allow for a unique way to estimate ages. Small craters (less than about 400 meters) typically do not last very long on the lunar surface because they are disturbed by ongoing micrometeorite impacts. Furthermore, when an image shows that a scarp cuts across a crater, it means the scarp is even younger than the crater. By analyzing scarps and their underlying craters, some scarps are thought to be less than a billion years old, and could be as young as a hundred million years old.
(NASA)