Geology Terms O: Obsidian Oceanic Volcanoes Octahedral Coordination Oil Field Oil shale Old Age Oolite Opaque Mineral Ophiolite Suite Orbit Ore Ore Mineral Original Horizontality, Principle of Orogenic Belt Orogeny Oscillation Ripple Outcrop Outgassing Outwash Oxidation Oxidized Element. [100%] 2023-02-24 [Geology Terms]