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What Kind of Rocks Were Found on the Moon?

Man has been fascinated by the moon for thousands of years. Astronomers speculated what might be on the moon the same as they speculate today about faraway planets in the rest of the solar system and universe. Man's understanding of the moon, what it contains and what kind of history it has, is greater than ever because of the effort that has gone in to studying it, traveling to it and bringing rock samples back from it to study.

  1. Primary Rock Types

    • Anorthosite and basalt are the primary types of rocks found on the moon's surface. Basalt types of rock are darker because they contain a lot of iron, which absorbs light. Anorthosite samples contain the lighter mineral feldspar. Rock samples brought back after Apollo Lunar landings tell the history of a land surface that has been battered repeatedly by meteors. Many rocks show signs of being melted by the impact of these meteors.

    Lunar Mare Basalts

    • Lunar mare basalts are volcanic igneous rocks generated by the heat induced through gigantic meteors hitting the surface of the moon. Lava erupted in the crater basin and cooled slowly, which caused the unusual texture. Some mare basalts have textures that indicate the lava was crystallizing progressively while it cooled; others have textures that indicate they cooled more rapidly. These are younger rocks and show little evidence of shock metamorphism from meteors hitting them.

    Plutonic Igneous

    • Most of the lunar highland is covered with Plutonic igneous rock, the original rocks of the moon. These are very old rocks and show significant shock metamorphism from meteorites hitting the moon. All Plutonic igneous rocks --- anorthosites, norites and troctolites --- have feldspar, but only the anorthosites are completely feldspar. The other two also contained olivine and pyroxene, respectively. The older crust was rich with feldspar, which when melted became buoyant and floated to the surface.

    Lunar Impact Breccias

    • Lunar impact breccias is the most common type of moon rock, they are made from the debris of meteors that hit the moon. The heat from the collision cemented the rocks together. Breccias are either monomict, meaning they contain only one kind of rock, or polymict when they contain more. Breccias lie over large regions of the moon's surface and have been mapped using a telescope. Most of the rocks are polymict.

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