7th Grade Unit 8: Natural Events that Change the Environment Lesson 2: Effects of Weathering and Erosional Deposition Vocabulary of Instruction: Video: Basics of Geology 1. Abrasion • Refers to the grinding away of rock by rock particles carried by water, ice, wind, or gravity. 2. Bioerosion • The process by which animals, through drilling, grazing, and burrowing, erode hard substances such as rocks and coral reefs. Crossbedded rippled burrowed sandstone. 3. Carbonation • Is a form of chemical weathering where carbonate and bicarbonate ions react with minerals that contain calcium, magnesium, potassium, and sodium. 4. Chemical Weathering • The process that breaks down rocks through chemical changes. 5. Climate • General pattern of weather conditions for a region over a long period time. Moist Climate Dry Climate 6. Deposition • Where the agents of erosion (water, wind, animals, etc.). lay down sediments. 7. Exfoliation • The breaking off of thin concentric shells, sheets, scales, plates, and so on, from a rock mass; measuring less than a centimeter to several meters in thickness, the loosened rock is spalled or fragmented, peeled, or stripped. 8. Gravitational Erosion • Caused by gravity and involves both large scale mass wasting and smaller scale erosion. Forms of gravitational erosion include avalanche, landslide, debris flow, mudflow, and sinkhole formation. 9. Hydrolysis • The chemical reaction of a compound with water. Hydrolysis is an important component of soil formation, and of chemical weathering. 10. Ice Wedging • Wedges of ice in rocks widen and deepen cracks. 11. Mass Movement • Any one of several processes that causes a down slope movement of sediment, soil, and rock material. 12. Mechanical Weathering • The type of weathering in which rocks is physically broken into smaller pieces. 13. Oxidation • Is when a substance reacts with oxygen to form a type of compound known as an oxide that contains at least one oxygen atom. 14. Thermal Expansion • Characteristic property of most solids and liquids which causes their volume to increase when they are heated. 15. Weathering • Physical, chemical, or biological breakdown of rocks and minerals into smaller sized particles.