BRECCIA IN BRECCIA Some rock fragments found in breccias are pieces of more ancient breccias. Repeated impacts have smashed the older rock and re-fused it with more recently formed breccia. As many as four generations of breccia have been found in a single lunar rock. GRANULATION A common feature of many lunar crystalline rocks is the grinding and crushing, or granulation, of their minerals caused by repeated meteoric bombardment. This makes the original textures difficult to recognize. SHOCK MELTING A glassy material produced by the shock of a meteoric impact coats this rock fragment from an Apollo 11 breccia sample. Since the glass is not uniform in composition, it strongly indicates that the glass was formed by shock. SHOCK MELTING This ellipsoidal lunar glass particle contains numerous tiny spheres of nickel-iron. These metallic spheres are meteoric in origin and indicate that the glassy particle was produced by shock melting during a meteoric impact. Apollo 17 Breccia

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