G11 Earth Science (Midterms).pdf

Earth Science  Bioturbation Midterms | 11 STEM Classification of Sedimentary Rocks ___________________________________________ 1. Detrital...

Earth Science  Bioturbation Midterms | 11 STEM Classification of Sedimentary Rocks ___________________________________________ 1. Detrital - derived from rock fragments Rocks Examples:  It is a fundamental component of the geosphere.  Conglomerates & Breccias  Sandstones  It is naturally occurring solid material consisting of one or  Siltstones more minerals.  Claystone Rock Cycle 2. Chemical - formed from precipitation of solutions rich in mineral components  It shows how each of the three principal types of rocks (sedimentary, metamorphic, and igneous) can evolve Examples: into either of the two other types of rock, or even into  Carbonate-based (CO3) like Limestone, Chalk, Travertine other rocks of its own type.  Silica-based (SiO4)  Halite  It transforms rocks from one type to another depending on the temperature and pressure where these transformations occur. Metamorphic Rocks Sedimentary Rocks  Rocks that are subjected to heat and pressure.  It is formed when rocky material experiences intense heat  Sediments that are compacted and cemented. and pressure in the crust of the earth.  It is composed of geologically reworked materials, formed  Most metamorphism, the process of forming by the accumulation and consolidation of mineral and metamorphic rocks, occurs at depths of between about 10 particulate matter deposited by the action of water or, and 30 km (about 6 to 18 mil). less frequently, wind or glacial ice.  Through the metamorphic process, both igneous and sedimentary rocks can change into metamorphic rocks,  Weathering and erosion, which break down rocks and and a metamorphic rock can change into another type of create sediments, occur at or near the earth’s surface. metamorphic rock.  Heat and pressure do not change the chemical makeup of Formation of Sedimentary Rocks the parent rocks but they do change the mineral structure 1. Weathering and physical properties of those rocks. - processes of physical disintegration (breakdown) and chemical decomposition (decay) of solid rock materials at or Formation of Metamorphic Rocks near the earth’s surface A. Heat - the most important factor contributing to metamorphism 2. Erosion - “eat away” Examples: - removal of rock and soil material by natural processes,  Underground magma (contact metamorphism) principally running water, glaciers, waves, and wind  Produces by radioactive decay within the earth  Friction between bodies (plate tectonics) 3. Transport - movement of sediments from one place to another B. Pressure - dependent on the energy of the medium/agent - causes the rocks to compress into a smaller, denser form 4. Deposition 1. Confining Pressure - settling of sediments in an area before being lithified to - constant/uniform pressure on a rock body form sedimentary rocks 2. Differential Pressure Diagenesis - dominance of a particular direction with respect to  Compaction pressure  Cementation  Recrystallization Lithostatic  The magma from which they form often intrudes  It is what rocks that are buried deep beneath many layers into the neighboring rock. of rock experience.  In Greek, “lithos” means rock; “statikos” means in place. 2. Extrusive/Volcanic Rocks - rocks formed at the surface of the earth C. Chemically-active Fluids - water or fluids (under intense heat and pressure) dissolves  The magma has extruded, or erupted, through a and assists in ion transfer to add or remove mineral volcano or fissure. components B. Classification by Composition Classification of Metamorphic Rocks 1. Plutonic rocks have mineral grains that are easy to identify 1. Foliated using the naked eye or hands lens (phaneritic texture). - subjected to differential pressure 2. Volcanic rocks are too finely grained to identify the chemical composition (aphanitic texture). Examples:  Slate  Felsic (rich in silicon)  Phyllite  Mafic (rich in magnesium and iron, but low in silicon)  Schist  Ultramafic (very low in silicon)  Gneiss  Intermediate (composition between felsic and mafic) 2. Non-foliated - similar to igneous rocks - classified according to composition Igneous Rocks  Rocks that are melted and then cool.  These are rocks formed from a molten or partly molten material called magma. Magma  It forms underground when rock that was once solid melts. Economic Important of Igneous Rocks  Overlying rock presses down on the magma, and the less  Many types of igneous rocks are used as building stone, dense magma rises through cracks in the rocks. facing stone, and decorative material, such as that used  Melting of common rock-forming minerals is around 600- for tabletops, cutting boards, and carved figures. 1100 Celsius.  Igneous rocks may also contain many important ores as accessory or trace minerals. Crystallization/Cooling  Kimberlites, formed from magmas from deep within the  It is the process that transforms magma into solid igneous earth, are the primary source of diamonds. rock.  Newly formed igneous rocks are also hot and can be an important source of geothermal energy. Lava  It is the magma that reaches Earth’s surface. Minerals  It loses heat to the atmosphere or ocean very quickly and  It is naturally occurring, inorganic, solid with definite therefore solidifies very rapidly, forming very small chemical composition, and ordered internal/crystalline crystals or glass. structure. Igneous Rock Formation Naturally Occurring The magmas that form igneous rock are hot, chemical soups containing a complex mixture of many different elements.  It should be made by natural process without the aid of any organism, found in nature, forms underground, and Types of Igneous Rocks not made by humans. A. Classification by Depth of Formation 1. Intrusive/Plutonic Rocks Inorganic - rocks formed within the earth  The mineral cannot come from things that were once living. Solid  It is something that is uniform in appearance and is in solid state of matter. Definite Chemical Composition  It possess uniformity in its chemical composition. Polymorphs - minerals that share common chemical composition Ordered Internal/Crystalline Structure  It has elemental components arranged in an ordered fashion and is a repeating pattern of mineral’s particles that line up when the form. Crystals - a beautiful planar faces that are often associated by cut or polished gems Different Crystal Systems  Cubic (Magnetite)  Hexagonal (Quartz)  Tetragonal (Rutile)  Orthorhombic (Sulfur)  Monoclinic (Azurite)  Triclinic (Microcline)