Review 4 Weathering Erosion and Deposition Weathering Breakdown
Review 4 Weathering, Erosion, and Deposition
Weathering- Breakdown of rocks into particles called Sediment Weathering occurs when rocks are exposed to: 1. Atmosphere 2. Hydrosphere 3. Living things
TYPES OF WEATHERING 1. Physical - Breakdown of rock into smaller pieces without chemical change. EXAMPLES: a) Root Action: Plant roots grow through cracks and break the rock.
b) Frost Action water freezes and expands in cracks. As this happens over and over again the rock breaks. c) Exfoliation: surface of the rock “peels” off.
d) Abrasion: When rocks or sediments rub against another rock ex: sandblasting
2. Chemical - Breakdown of rock by chemical action that results in a change in mineral composition EXAMPLES: a) Oxidation - When elements the rock react with O 2 (oxygen) Fe (iron) + O 2 (oxygen) = | Fe 2 O 2 (iron oxide or rust) in
b) HYDRATION- When elements in the rock react with H 2 O (water- the “universal dissolver”) Feldspar (common mineral) + H 2 O = Clay = fine particles that are usually wet
c) CARBONATION- When elements are dissolved by acid rain. Carbon Dioxide + Water = Carbonic Acid or Sulfur Dioxide + Water = Sulfuric acid Example: Marble grave stone dissolved by acid rain
PRODUCTS OF WEATHERING Weathering results in four types of sediment: 1. Solid sediment - sand pebbles. 2. Colloids clay sized particles (small sediment) 3. Ions - Particles dissolved in water (salty oceans) 4. Soil - a mixture of sediment and organic matter
O=dark organic layer A= topsoil, highly weathered rock mixed with organically rich material B=Subsoil, less organic material and weathered rock C-weathered rock and parent material D- Bedrock base.
Deposition • I. Deposition is the process by which sediments are RELEASED, SETTLED FROM, or DROPPED from an erosional system.
II. Factors that Affect Rate of D • A. Size • 1. Larger sediments will settle FASTER. [Think of the ESRT! Bigger sediments are harder to carry. ]
What is erosion?
- Slides: 20
