Weathering and Erosion

Weathering  The processes that break down rock into smaller pieces.

Sediment  Small pieces of rock Examples of Sediment:  Gravel  Sand  Silt  Clay

Mechanical Weathering  Occurs when rocks are broken down by physical processes. The rocks get smaller, but do not change chemical makeup.

Types of Mechanical Weathering  Plants and animals – Examples: tree roots and burrowing animals

Types of Mechanical Weathering  Ice wedging – water gets between the cracks in the rocks, freezes and breaks them apart. Example: cracks in sidewalks

Chemical Weathering  Occurs when chemical reactions dissolve minerals in rocks or change them into different minerals.

Types of Chemical Weathering  Natural acids – break down rocks. Examples: caves; feldspar turns into clay Examples: caves; feldspar turns into clay

Types of Chemical Weathering Plant acids- acids are released from plants and dissolve rock over time. Ex: Lichen

Types of Chemical Weathering Oxidation - Metallic minerals exposed to water and oxygen over time. Example: rust Oxidation - Metallic minerals exposed to water and oxygen over time. Example: rust

Erosion The movement of sediment from one place to another. The movement of sediment from one place to another. Forces of Erosion: wind, water, ice, gravity

Deposition  The laying down of sediment by water, wind, glaciers or gravity  Examples: river delta, glaciers

Forces of Erosion  Mass movement (mass wasting) - erosion from gravity moving sediment down a slope

Types of Mass Movement  Slump – when a section of material slips down a slope and breaks off.

Types of Mass Movement  Rockfall – pieces of rock fall and cause other rocks to fall. Usually happens in the winter. the winter.

Types of Mass Movement  Rock slide- rocks slide down a slope at once. Usually happens after heavy rain or during earthquakes

Types of Mass Movement  Mudflow (mudslide)- rain mixes with soil to form mud, slides downhill

Types of Mass Movement  Creep- when sediment slowly shifts, trees and other objects lean forward

Wind  the less vegetation, the greater wind can affect erosion.

Glaciers  as a glacier moves, sediment moves with it causing erosion

Water  rivers and oceans can cause erosion

Animals  Humans and other animals can impact erosion.

 Glue these notes in your journal.  Be sure to label table of contents  Write a 1 paragraph summary of weathering and erosion