Geology12345
Terms
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- Rocks exposed at Earth’s surface are ______ __________ by water, air, temperature variations and other factors
- constantly changed
- ____________ is the group of destructive processes that change physical and chemical character of rocks at or near Earth’s surface
- Weathering
- ________ is physical removal of rock particles from the point of weathering by water, ice, or wind
- Erosion
- ___________ is the movement of eroded particles by water, ice, or wind
- Transportation
- ______________ •The mechanical and chemical breakdown, dissolution, and alteration of Earth materials at the Earth’s surface •Occurs because minerals formed at higher T and P and different chemical conditions are unstable at low T and P and in th
- Weathering
- Weathering products: _______, _______, _______,_______, and _______.
- ⬢Sediments ⬢Soils ⬢Salts in solution (seawater) ⬢Nutrients for plant growth ⬢Economically valuable deposits
- types of weathering: _________ __________ –Physical disintegration –Frost action, pressure-release fracturing, plant growth, burrowing animals, salt wedging, thermal cycling
- Mechanical weathering
- types of weathering: ___________ ________ –Decomposition of rock from exposure to atmospheric gases (oxygen, water vapor and carbon dioxide) –New chemical compounds (minerals) form –Rate increased by increased rock surface area from mechanical w
- Chemical weathering
- mechanical weathering: ________ __________ –Water expands as it freezes to ice –Creates stress in cracks in rock
- Frost Action
- mechanical weathering: ________ ________ -Crystals growing in cracks create stress
- Salt Crystal Growth
- mechanical weathering: ________ _________ –Large temperature changes fracture rocks by repeated expansion and contraction
- Thermal cycling
- mechanical weathering: ___________ __________ –Rocks which formed at higher pressure within the Earth expand slightly as they near the Earth’s surface (upon removal of overlying materials by erosion) –Causes the formation of Sheet Joints, cracks
- Pressure release
- mechanical weathering: ________ _________ –Growing roots widen fractures
- Plant growth
- chemical weathering: _________ –The addition of oxygen from atmosphere to minerals •Example: Iron + Oxygen = rust (hematite) –Iron oxides are common result •Soil and sedimentary rocks often stained with iron oxides
- oxidation
- chemical weathering: ___________ –Dissolving of minerals by natural acids (naturally formed corrosive liquids) –Hydrogen cations from acids replace other cations in minerals –Carbonic acid forms from atmospheric CO2 dissolved in water –Sulfur
- solution
- __________ •Layers of loose, solid particles from: –Weathering and erosion of preexisting rocks –Chemical precipitation from solution
- Sediment
- _______ •Sediment that contains abundant organic material and supports plant growth –Common soil constituents: •Clay minerals •Quartz •Iron & Aluminum Oxides •Water •Organic matter
- Soil
- ___________- weathering of underlying rock
- Residual soil
- ____________- brought in from elsewhere –Floodplain deposits, etc. –Wind-transported sediment is called loess
- Transported soil