1. Maria (Lunar Seas):
* Description: The dark, smooth plains visible on the Moon's surface. They are vast, impact basins filled with solidified lava.
* Formation: Early in the Moon's history, it was heavily bombarded by asteroids and meteorites. These impacts created massive craters, some of which reached the lunar mantle. Molten rock, called magma, from the mantle erupted and flowed into these craters, eventually solidifying to form the smooth, dark plains we see as maria.
2. Lunar Highlands:
* Description: The lighter, heavily cratered regions on the Moon, surrounding the maria. They are composed of anorthosite, a light-colored rock rich in calcium and aluminum.
* Formation: The lunar highlands represent the original crust of the Moon, formed during the early stages of its formation. The intense heat from the Moon's formation caused the lighter, less dense minerals to rise and solidify, creating the highlands. Subsequent impacts created the many craters we see today.
These two features, the maria and the highlands, tell a story of the Moon's violent early history, from its initial formation to its later bombardment and volcanic activity.