weathering the process by which materials on or near the earth’s surface break down and change
TRANSCRIPT
![Page 1: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/1.jpg)
WeatheringWeatheringThe process by which materials on or near the Earth’s surface break down and change.
![Page 2: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/2.jpg)
1. Mechanical / Physical 1. Mechanical / Physical WeatheringWeatheringRefers only to the physical breakdown of
matter (as opposed to chemical breakdown)◦Frost Wedging: Water expands in volume by
9%. As water infiltrates cracks in rock causes additional cracking due to freeze-thaw cycles
◦Pressure: pressure on underlying rock is consistent until erosion, or another process, removes matter. The reduction in pressure can cause elastic energy within underlying rock to be released. This looks likes widening cracks or fractures
![Page 3: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/3.jpg)
![Page 4: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/4.jpg)
![Page 5: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/5.jpg)
![Page 6: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/6.jpg)
1. Mechanical / Physical 1. Mechanical / Physical WeatheringWeatheringRefers only to the physical
breakdown of matter (as opposed to chemical breakdown)◦Exfoliation: As pressure cycles and
freeze-thaw cycles proceed, outer layers of rock can be stripped away in succession (like an onion)
![Page 7: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/7.jpg)
![Page 8: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/8.jpg)
1. Mechanical Weathering1. Mechanical WeatheringThe rate of physical weathering is
relatively high in cool climates. ◦Frost wedging / freeze-thaw cycles◦Cool climates are not ideal for
chemical reactions / dissolution
![Page 9: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/9.jpg)
Pylon of Ramses II, EgyptPylon of Ramses II, Egypt
Cleopatra’s Needle, New YorkCleopatra’s Needle, New York
![Page 10: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/10.jpg)
Surface Area versus Surface Area versus VolumeVolumeAs rocks break down into
fragments, they maintain the same volume, but increase their surface area.Side
LengthVolume Surface
Area
1 cm 1 cm3 6 cm2
2 cm 8 cm3 24 cm2
3 cm 27 cm3 54 cm2
![Page 11: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/11.jpg)
![Page 12: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/12.jpg)
![Page 13: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/13.jpg)
2. Chemical Weathering2. Chemical WeatheringProcess by which rocks and
minerals undergo changes in their composition and is dependent on a mineral’s chemical composition and temperature◦Oxidation: reaction with oxygen.
EX Iron and Oxygen = Iron Oxide (Hematite)
◦Water: able to dissolve minerals and rocks. Water may also act as a medium in which reactions can occur.
![Page 14: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/14.jpg)
![Page 15: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/15.jpg)
2. Chemical Weathering2. Chemical Weathering◦Carbon Dioxide: when CO2
(from living and decaying organic matter) reacts with water in the atmosphere it produces carbonic acid that falls to Earth as acid precipitation which then cuts through mineral and rock.
◦Acid Precipitation: Usually at pH 5.6 or below Carbon dioxide, Sulfur
dioxide
![Page 16: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/16.jpg)
![Page 17: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/17.jpg)
2. Chemical Weathering2. Chemical WeatheringRate of chemical weathering is
relatively high in climates with warm temperatures, abundant rainfall and lush vegetation.
Chemical weathering has the greatest effect at, and around the equator.
![Page 18: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/18.jpg)
![Page 19: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/19.jpg)
Transportation of Weathered Transportation of Weathered MaterialsMaterialsErosion:
◦The removal of weathered rock and soil from its original location.
◦Running water, glacier, wind, ocean currents, and waves.
◦When material ‘drops’ after being eroded it experiences deposition.
![Page 20: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/20.jpg)
Erosion by WaterErosion by WaterRill erosion: Running water cuts
small channels into the side of a slope.
Gully erosion: Rill erosion eventually becomes gully erosion as the channel widens.
![Page 21: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/21.jpg)
![Page 22: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/22.jpg)
![Page 23: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/23.jpg)
Glacial ErosionGlacial ErosionGlaciers account for < 10% of
Earth’s water, yet cover about 30% of Earth’s surface (due to expansion)
Scrape out large sections of Earth’s landscape
![Page 24: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/24.jpg)
Erosion by Wind and by Erosion by Wind and by Living ThingsLiving Things
???
![Page 25: Weathering The process by which materials on or near the Earth’s surface break down and change](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e3f5503460f94b2ffa5/html5/thumbnails/25.jpg)
Try thisTry this◦Complete Q: 1-5 on page 170◦Complete Q: 1-4 on page 175