Which type of meteorite is composed of oxygen, silicon, magnesium, and some iron?

The correct answer describes an aerolite, also known as a stony meteorite. These meteorites are primarily composed of silicate minerals, which contain elements such as oxygen, silicon, and magnesium. Additionally, they may include some iron, which can be present in various forms within the mineral structure. Aerolites are the most common type of meteorites found on Earth, constituting a significant portion of all meteorite falls.

This classification reflects the composition of the material that forms the celestial bodies in our solar system. Unlike siderites, which are predominantly metallic and mostly composed of iron, or tektites, which are formed from terrestrial materials ejected during meteorite impacts, aerolites are mineral-rich and provide key insights into the geological processes of their parent asteroids or planetary bodies. Thus, the defining characteristics and elemental makeup of aerolites align perfectly with the question's description.