- Slides: 16
Rocks, and More Rocks
Types of Rocks • Igneous rock Pumice – Forms when magma cools and hardens – Can form underground or above ground – Types of igneous rock: • • Granite Scoria Pumice Obsidian Scoria
Types of Rocks • Wind and water can break igneous rock into sediments. Igneous Rock Sediments Wind and Water Cementation Sedimentary Rock • When the sediments are cemented into a layer over time, igneous rock becomes sedimentary rock. • What causes the cementation?
Types of Rocks • Sedimentary Rock – Common types include chalk, limestone, and clay – Often contains fossils – Types of Sedimentary rocks • Clastic: made up of different rock fragments • Biogenic: contain materials from organisms such as corals • Precipitate: rocks formed when water evaporates such as halite (rock salt left behind after sea water evaporates)
Types of Rocks • Weathering and erosion will revert sedimentary rocks back to sediments. • Heat and pressure change sedimentary rock to metamorphic rock. Sediments Weathering and Erosion Sedimentary Rock Heat and Pressure Metamorphic Rock
Types of Rocks • Metamorphic Rock – Make up a large part of the Earth’s crust – Common examples include slate, shale, and mudstone – Can go through foliation, a process where the randomly distributed minerals in the rock become organized in a parallel manner – Foliation cause cleavage or breakage of the rock at weak cracks
Foliation The disorganized minerals become more organized.
Cleavage Weak areas are prone to breakage.
Types of Rocks • Very high heat melts metamorphic rock into magma. • Weathering and erosion will change metamorphic rock back to sediments. Sediments Weathering and Erosion Metamorphic Rock Magma Melting
Magma (molten rock) • A hot liquid made of melted minerals • Called lava when it appears on Earth’s surface, usually from volcanic vents • The temperature of magma can range from 650 to 1200 °C • Created by heating rock under extreme temperatures • Cooling magma creates igneous rock
Rock Cycle Igneous Rock Cooling Magma Melting What does melting What do do does heat What doand cooling Which rock becomes What the weathering and metamorphic rock compaction and pressure to do weathering and magma create? metamorphic rock melting of igneous erosion do create? cementation doall to sedimentary rock? erosion do to to this under heat and rock create? types of sediments? type of rock? pressure? Metamorphic Rock Heat and Pressure Weathering and Erosion Sediments Cementation Sedimentary Rock
Minerals • Rocks are made up of one or more types of minerals. • True minerals have the following characteristics: – Solid – Have a crystal structure – Inorganic and naturally occuring – Defined chemical composition
Minerals • Ways to classify minerals: – Hardness: how hard the material is – Luster: how the surface interacts with light – Metallic: metallic qualities such as reflectivity – Color: what color the material is – Magnetism: the rock’s ability to attract other metals – Fluorescence: appearance under UV light
Erosion • Erosion is the movement of particles by wind, water, ice, or gravity. • Erosion is a natural process that can be increased by human land use. • Steep slopes, lack of vegetation, and land use can increase the rate of erosion. • How does erosion differ from weathering?
Erosion • Types of erosion include: – Gravity erosion – Water erosion – Shoreline erosion – Ice erosion – Wind erosion • Can you explain what occurs in each of these types of erosion?