6/12/20161 Weathering/Erosion Ms. Margolles

6/12/20162 Topics of Discussion Weathering Chemical & Mechanical weathering Mass movements Running water Glaciers wind

6/12/20163 Weathering Weathering is the breakdown of rock into smaller pieces by natural process. Exposure to air, water, and living things causes weathering.

6/12/20164 Two Types of Weathering: Mechanical weathering: Process that breaks down rock without changing the chemical composition. Chemical Weathering: Process that breakdown rocks and changes the composition; chemical changes occur as the rock is exposed to the environment.

6/12/20165 Mechanical Weathering Examples: Frost action Abrasion Is the physical wearing down of rocks as they rub or bounce against each other. This process is most common in windy areas, under glaciers, or in stream channels. Exfoliation is the peeling away of large sheets of loosened materials at the surface of a rock. Common in shale, slate, and mica Plants/animals/humans

6/12/20166 Chemical Weathering Examples: Oxidation occurs when oxygen interacts chemically with minerals. For example, when a nail rusts oxygen combines with the iron in the nail to form iron oxide. Hydration occurs when water interacts chemically with minerals. For example, when hornblende and feldspar unite with water they eventually form into clay. Carbonation occurs when carbon dioxide interacts chemically with minerals. When carbon dioxide is dissolved in water, it forms weak carbonic acid. Carbonic acid when it comes in contact with the surface of the earth dissolves large masses of limestone, creating caves and caverns. Other common terms associated with carbonation are sink holes, karst topography, stalactites and stalagmites.

6/12/20167 Damaged by Acid rain

6/12/20168 What are the products of weathering? Sediments: Rock fragments produced by weathering Sediments are named according to the size of the pieces Soil Soil is made of weathered rocks and humus (decayed organic material)

6/12/20169 EROSION Movement of rock material from one place to another. Weathering breaks down solid rock and erosion carries away the pieces.

6/12/ Mass Movements Caused from gravity Occur on steep slopes Increase with rain flow

6/12/ Slump (mass wasting) Steep slopes Slope: an elevated geological formation; Material underneath has weakened

6/12/ Creep Small sediments are pushed up during freezing and slide down when thaw Creep is the tendency of a solid material to slowly move or deform permanently under the influence of stresses Downhill creep, or commonly just creep, is the slow downward progression of rock and soil down a low grade slope

6/12/ Rock Slides (mass wasting) Large blocks of rock break loose from steep slopes

6/12/ Mud Flows (mass wasting) Add a strong statement that summarizes how you feel or think about this topic Summarize key points you want your audience to remember

6/12/ Deposition The processes by which transported sediments are dropped off in a new location As the agent of erosion slows down, more particles will be dropped off on the ground.