Vocab Notes

1. Vocab Notes Weathering and Erosion

2. Chemical Weathering • Rocks broken down by reacting with gases, water, and solutions • Chemical reactions break down the bonds holding rocks together, causing them to fall apart • Happens in almost all rock types • Smaller rocks = more surface area=more susceptible • More water and warmer temps= better for this weathering • http://library.thinkquest.org/20035/chemical.htm • http://facstaff.gpc.edu/~pgore/geology/geo101/weather.htm • http://www.kidsgeo.com/geology-for-kids/0067-chemical-weathering.php • Ex: rust on metal in soil, soil becomes red- brown to red. (oxidation)

3. Mechanical Weathering • is the process by which rocks are gradually broken into smaller pieces down without changing their chemical composition • Only shape and size changed • http://library.thinkquest.org/20035/chemical.htm • Ex: stream grinding at the bank Root wedging fracture in granite

4. Surface Area A rock that has been broken up has more surface area and can therefore be weathered more quickly • How much exposed area a surface has

5. Exfoliation • Rock peeling off in sheets rather than weathering grain by grain • Can be in paper thin sheets or large slabs • http://geology.about.com/library/bl/images/blexfoliation.htm Ex: Yosemite Valley, CA Exfoliating in thick slabs.

6. Frost Wedging • Type of mechanical weathering caused by the repeated freeze/thaw cycle of water • http://estes.on-line.com/rmnp/articles/frstwdg.html Process • Rainwater falls into the joints (cracks) • Temp cools w/ night • Water becomes ice and expands • Pressure put on joints • If it is too much, the joint will expand • After several freeze and thaws, the joint cracks

7. Atmospheric Carbonic Acid • Forms when carbon dioxide combines with water in the atmosphere • Falls as precipitation • Reacts with minerals to dissolve rocks • Can also react with element in minerals • Forms clay materials • Ex) limestone caverns formed when the acid dissolves the calcite in limestone rocks

8. Oxidation • Chemical reaction of oxygen with other substances • Ex) Iron in rocks and minerals readily combines w/ oxygen forming minerals with oxidized form of iron • Ex) green copper penny, freshly cut apple turning brown, rust

9. Acid Precipitation • Caused by oxidation of sulfur dioxide and nitrogen oxides released by human activities • Process • Sulfur dioxide from burning of fossil fuels & nitrogen oxides from motor-vehicle exhaust • Gases combine with oxygen and water in the atmosphere • Forms sulfuric and nitric acids • Gets into water system and falls as acid rain • Effects • Soil health – wipes out some microbes and essential nutrients and minerals • organisms ph levels • Weathering of buildings and statues • Speeds up natural weathering

10. Erosion • The removal and transport of weathered material • Ex) running water carries weathered materials, glaciers carve out an area and take materials elsewhere (gravity helps both processes) • Also wind and organisms http://facstaff.gpc.edu/~pgore/Earth&Space/erosion.html (good site)

11. Deposition • Materials being dropped in another location • Final stage of erosional process • Ex) rivers emptying into large body of water and depositing sediments = delta • Ocean currents repeatedly pick up and deposit sand along a shoreline

12. Gully Erosion http://www.iirr.org/saem/page84-92.htm • Removal of soil by running water along deep and wide channels • Ex) can be more than 3m deep. Can present major problems to farms

13. http://www.ipm.iastate.edu/ipm/icm/2001/5-21-2001/preventeros.htmlhttp://www.ipm.iastate.edu/ipm/icm/2001/5-21-2001/preventeros.html Rill Erosion • Erosion by running water in small channels on the side of a slope • Can form gully erosion • Repairing • Tillage, however it makes looser • Discing • Preventing • Terraces • Contour farming • Keep high level of residue (reduces soil detachment)

14. www.ga.nrcs.usda.gov/technical/soils/red.html Residual Soil • Soil located above its parent material • It was made there and hasn’t been moved from there • EX) Kentucky’s bluegrass soil, Georgia’s red soils

15. Soil • Process • Bedrock weathered into smaller pieces • Continue weathering • Organisms like bacteria, fungi,and insects begin to live in the weathered materials • Organisms die, decay, and add nutrients to create soil • Supports variety of life • Processes continue. Soil texture and water holding abilities improve • Soil- the loose covering of broken rock particles and decaying organic matter, humus, overlying the bedrock of Earth’s surface.

16. Soil Horizon • A distinct layer, or zone, within a soil profile • Three major horizons: A, B, and C • A- most developed, humus • B- subsoils enriched with clay materials, zone of accumulation, may be red (iron oxides) • C- weathered parent material and rock

17. Soil Profile • Vertical sequence of soil layers • Poorly developed soils show little distinction between layers, or not even have all layers • C is just above bedrock

18. Transported Soil • Soil that has been moved to a location away from its parent bedrock • Agents of erosion transport material (like wind, running water, glaciers) • Ex) streams and rivers transport and deposit much material, especially during times of flooding This river transports material

19. Land Use

20. Land Use