What Are the Three Types of Landforms That Make Up the Moon's Surface?
The moon's landforms are byproducts of meteor impacts and volcanic activity. The lunar surface can be divided into two main regions, the highlands and the maria. The highlands make up roughly 83 percent of the moon's surface, whereas the maria make up about 17 percent of its surface. Both of these regions have a characteristic density of craters from meteor impacts.
The countless craters on the moon were produced by meteor impacts on the lunar surface. Craters exist throughout the lunar surface, but different regions have different cratering density. In general, the cratering density of a region correlates with its age. A younger region of the moon's surface will have fewer craters, because it has not been in existence long enough to acquire a large number. Older regions will have more craters. Ultimately, a region can achieve maximal crater density, which means that any new craters will erase or alter older ones.
The maria are the moon's dark regions. "Maria" is Latin for "seas" (the singular is "mare"). However, the maria do not contain water. Instead, they are the remnants of lava flows on the moon's surface. The lava flowed through cracks in the moon's crust and cooled on its surface. The maria are roughly 1 to 4 kilometers (0.62 to 2.5 miles) thick. Almost all the moon's maria are on the side of the moon facing Earth; the Earth-facing side is 30 percent maria, whereas the far side is only 2 percent maria.
The moon's highlands are its old, mountainous regions. They are light in contrast to the moon's maria. The highlands consist primarily of anorthosite. Anorthosite is an igneous rock that forms when lava cools very slowly. The highlands also have many craters. This implies that the highlands are an old landform on the moon's surface. In fact, the Apollo 16 and 17 missions collected rock samples from the lunar highlands that were 4 billion or more years old.
While the craters, highlands and maria are the moon's three main landforms, the moon's surface has a number of other highly visible features. For example, some impact craters have bright rays that shoot outward from the center. Also, the moon has a number of rilles, which are long, thin tunnels or trenches. These features are present in the maria, and are a byproduct of lava flow. Lastly, the moon has domes scattered throughout its surface. These domes are thought to be volcanic in nature.
Serm Murmson is a writer, thinker, musician and many other things. He has a bachelor's degree in anthropology from the University of Chicago. His concerns include such things as categories, language, descriptions, representation, criticism and labor. He has been writing professionally since 2008.