Due to the ground movement beneath the Mare Frigoris, the pleated ridges are often squatted along the ground for miles. The longest is about 250 miles (400 kilometers), which is greater than the distance between New York City and Washington, up to 1,000 feet (333 meters). The push and pull of the moon's crust also shaped a curved hill called the steep slope of the leaf and a shallow ditch called the mantle.
Geologists can also determine their age by studying another common feature of the Earth: craters. The longer the surface is hit by a meteor, the more debris it produces, covering the nearby terrain and changing the landscape. This process is called “impact gardening”.
The longer the circumference of the crater, the more debris is collected. The smaller they are, the less time they fill up: the size of a football field crater can usually fill up in a billion years. The LROC image shows clear structural features, such as pleated ridges formed after a small, unfilled crater. So Williams and his co-authors inferred that these ridges were formed in the past billion years.