Geology 101Lab 3Monday, September 15, 2014Rocks and The Rock CycleChapter 4 and Chapter 5The Rock Cycle- Rocks are the solid materials that comprise nearly all of the earth, moon, and rocky planets- These earth materials are changed both on surface and inside the earth- The rock cycle is a conceptual model that explains how the various types of rocks are formed, deformed and transformed- Three types of rockso Igneous Form as molten (lava or magma) rock cools and solidifies- Basalt flow in Hawaiio Sedimentary Form from loose weathered sediment that is compacted and/orcemented together; or by precipitation out of a solution- Sandstone in Wyoming o Metamorphic  Formed as a result of intense heat and pressure- Gneiss in Canadian Rockies Igneous Rocks- Rocks that are formed when molten rock called magma cools- Magma is melted rock that can form in the earth’s crust and upper mantle- As magma cools and solidifies it forms- Igneous rocks are described by their texture and composition- Texture describes the size, shape, and arrangement of the crystals comprisingthe rock- In general, a slower cooling magma results in coarser grained igneous rockIgneous Rock Textures- Phaneritico Igneous rocks are coarse grained, consisting of a mass of intergrown crystals of roughly equivalent size that can be identified without the aid of a hand lens or microscope- Aphanitico Igneous rocks are very fine grainedo The crystals that comprise them cannot be distinguished by the naked eye- Porphorytico Igneous rocks have two distinct sized of crystals The larger crystals are termed phenocrysts and the surrounding smaller ones called groundmass- Pegmatitico Igneous rocks are very coarse grained Individual crystals of pegmatitic rocks exceed 1cm- Vesicularo Texture results from gas bubbles trapped within the magmao Very volatile and rich, mixed with the cooling, forms the cavities- Glassyo Texture results when unordered ions are “frozen” before they can unite into an ordered crystal structure- Pyroclastico Igneous rocks are composed of particles or fragments rather than interlocking crystals. They are produced by explosive volcanism.Igneous Rock Composition- Felsico Rocks have a high portion of light colored silicates  Quartz and feldspars Granite and rhyolite-only texture different. Coarse grain vs. finegrain- Intermediateo Rocks have moderate portions of light and dark silicate Diorite and andesite- Magico Have a higher proportion of dark colored silicates  Amphiboles, pyroxenes, and calcium rich plagioclase feldspars- Ultramafico Very high proportions of Fe-Mg rich silicated and are green because of high amounts of olivineInsert Chart from pictureBowen’s Reaction Series- Bowen’s Reaction Series provides visual representation of the order in which minerals crystallize from a magma of average