PEO 3 - Weathering Flashcards
What is the LeChatlier Principle?
A system at equilibrium, if disturbed, reacts so as to regain equilibrium under the new conditions.
What are the major active agents of weathering?
Atmosphere, hydrosphere, biosphere
What is the most important factor in weathering?
Water.
Water has _____ capacity.
Solvent
Water can take apart any ____ bonded material, some things are easy to take apart (think salt) and some things are more difficult.
Iconically
Water has _____ heat.
Latent
___ cal/g - Vaporization/condensation
540
___ cal/g - Freezing/Melting
80
What are the two types of weathering?
Chemical and mechanical
What kind of weathering breaks rocks down into smaller pieces with greater surface area/volume?
Mechanical weathering
What determine the dominant types of weathering?
Temperature and annual precipitation
What is the result of water flow into cracks in rocks and between mineral grains as ice lenses form (they attract water from adjacent areas)?
Freeze/thaw
Form of mechanical weathering
What creates exfoliation domes; most common for granite and to a lesser extent marble?
Unloading (sheeting or exfoliation) (these names mean the same thing)
Form of mechanical weathering
_____/_____ volume change is a result of what?
Seasonal/Diurnal
Temperature or water content
Mechanical weathering
Crystal growth is related to which form of weathering?
Mechanical weathering
Biological activity is related to which form of weathering?
Mechanical weathering
What three variables is chemical weathering dependent upon?
Temperature, topographic relief, precipitation (humidity)
Chemical weathering is mostly caused by interactions with what?
Water (removal of cations in solution)
What environment is best for chemical weathering?
A warm, gently sloping environment. Tropical rainforests have a large amount of chemical weathering.
What type of weathering results in a loss of oxygen?
Oxidation
Chemical weathering
What type of weathering is most important for carbonates and reacts with acidic water?
Dissolution
Chemical weathering
Which have the most relative solubility? (Fe, K, Ca, Mg, Al, Si, Na)
Ca, Na, Mg
Which has the least soluble relative solubility?
(Fe, K, Ca, Mg, Al, Si, Na)
Al
What is the most important chemical weathering process where water is the agent for exchange of the metallic cations, cations are removed from the solution?
Hydrolysis
Chemical weathering
