Transcript Rock Cycle
A. Rock Cycle A sequence of events involving the formation, destruction, alteration, and reformation of rocks. Grand canyon B. Types of Rocks 1. Igneous Rocks (igneous means formed by fire) Formed by cooling magma 95% of the Earth’s crust Most common – granite and basalt Intrusive – formed beneath Earth’s surface Extrusive – formed at Earth’s surface 1. Igneous Rocks (igneous means formed by fire) granite basalt obsidian pumice B. Types of Rocks 2. Sedimentary Rocks (weathered material) Found in upper portion of crust Sediments – accumulated weathered material carried by water, wind, or ice Most common – sandstone, shale, and limestone Weathering – breakdown of rocks into smaller pieces Erosion – transport of rocks from one place to another 2. Sedimentary Rocks (weathered material) sandstone limestone shale siltstone B. Types of Rocks 3. Metamorphic Rock (metamorphic means changed in form) Formed from pre-existing rocks that are transformed by high temperatures, high pressures, or both without melting Most common – marble and slate 3. Metamorphic Rock (metamorphic means changed in form) marble quartzite slate Mica schist C. Rocks are made of minerals Minerals – naturally formed, generally inorganic, crystalline solid composed of an ordered array of atoms having a specific chemical composition Some such as gold are composed of single elements Most minerals are compounds Most minerals are distinguished by their physical characteristics – crystal form, hardness, cleavage, luster, color, streak, and specific gravity Most Common Minerals – Silicates Feldspars and quartz are the most common silicates Silicates contain oxygen and silicon which make up 46.6% and 27.7% of the Earth’s crust – 95% of the continental crust is made up of feldspar and quartz feldspar (orthoclase), KAlSi3O8 quartz (amethyst), SiO2 2nd Most Common Minerals – carbonates The carbonate ion (CO32-) can bond with a variety of other ions to produce the carbonate minerals. Calcite is the most common carbonate. All carbonate dissolve easily in acidic water calcite (CaCO3) azurite (Cu3(CO3)2(OH)2) malachite (Cu2CO3(OH)2) Other Common Minerals – oxides and sulfides Oxides O-2 ions corundum (Al2O3) magnetite (Fe3O4) Sulfides S-2 ions galena (PbS) millerite (NiS)