Weathering Flashcards
What is weathering?
Processes of change of rocks, minerals, soils
What are the types of weathering on
Earth? Give an example of each.
Physical-Water expanding in the cracks of a rock
Chemical-Caves or rusting
Biological-roots growing and breaking a rock
What types of weathering occur on
Earth’s moon?
Physical
Does weathering occur on Mars? Give an
example.
Yes; ventifacts in Gusev Crater
What type of weathering produced Meteor
Crater?
Physical?
What are ventifacts?
Rock that has been physically shaped by the wind and sand
What features of basaltic flows indicate
weathering? Which type?
columnar basalts ; cracking ?
What is the importance for weathering of
rock fragments?
What is a freeze-thaw cycle? Where does
freeze-thaw weathering occur?
Freezing and thawing of water inside of mountains generating 2000 psi. Pikes Peak, CO
What is a pluton? What happens during
the “unroofing” of a pluton?
Any crystallized mass of magma underground ; The surface has to be weathered away
What is the “geopressure gradient”? What
is the “pressure” at a depth of about 15
km?
change of pressure with depth ; aproximately 4,000 psi per km of depth ; 60,000
What are the three major categories of
weathering products?
Which chemically reactive compounds in
Earth’s atmosphere are important
because they drive chemical weathering
processes?
O2, H2O, CO2 > atmospheric gases
What is oxidation weathering? Give an
example.
Dissolved iron combining in streams with oxygen
What is hydrolysis? Give an example.
Water breaking the bonds of an atom apart ; dissolving ; mixing salt in water
What is carbonic acid? What feature
makes it an acidic compound?
When H2O picks up a CO2 and becomes H2CO3. Carbonic acid is rain
What is the pH of natural rain?
5.5
Is a sample of river water with a pH of 6.5
more or less acidic than a sample of
rainwater with a pH of 7?
more acidic
How much less acidic is a sample of well
water with a pH of 6.5 more compared to
a sample of rainwater with a pH of 5.5?
1/10
How much more acidic is a sample of well
water with a pH of 3.5 more compared to
a sample of rainwater with a pH of 5.5?
100 x
How does the pH of groundwater
compare to the pH of rainfall? Explain.
pH of groundwater is lower than pH of rainwater
What effect does groundwater have on
the mineral CaCO3 (and the rock
limestone)? Explain.
It weathers the rock and creates caves.
What conditions are required for forming
caves in limestone?
Hydration and carbonation
Why, and how, do sinkholes form?
When a caves roof collapses into the cave because it can no longer support itself.
How does the chemical weathering of
rock affect the concentration of CO2 in
the atmosphere?
If the chemical weathering of rock “uses
up (removes)” CO2 from the atmosphere,
where does the CO2 eventually go?
What mineral is a major source of clay by
chemical weathering?
Feldspar
What is the most, and second-most,
abundant mineral, in the sand of Alabama
beaches? Where does most of this sand
come from? How does it get to the
beach?
Quartz, Feldspar. Mount Cheaha. Wind and erosion.
What is the most abundant silicate
mineral in Earth’s crust? 2nd most
abundant?
feldspar ; quartz
Why is the ocean “salty”? Where does the
“salt” come from? What is “salt”, anyway?
- Chemically reactive water
- Dissolution of continental rock
- Transport of ions to oceans
- Evaporation of oceans leaving ions behind in the sea
What is soil? Why is it important to
mankind?
Weathered rock and minerals capable of supporting plant life. It allows us to grow food.
What major factors affect the formation of
soil?
Parent material, biota, climate, topography, and time
How do temperature and rainfall,
important factors of climate, each control
the rate of soil formation?
Warm weather encourages plant growth and rainfall causes leeching as well as dissolving some minerals.
What are soil horizons? In what order do
soil horizons form? What are the
characteristics and properties of these
soil horizons?
is a layer parallel to the soil surface, whose physical characteristics differ from the layers above and beneath.
What are the names and characteristics
of the three major types of soils?
Heavy soil-Large component of clay ; heavy, sticky, and many fine particles
Medium soil-containst nutrients essential for plants, and holds water well
Light soil-drain quickly do not hold water ; sandy
What happens during the “salinization” of
soil? Does salinization increase or
decrease agricultural production?
From poorly drained lands with high evaporation rate.
decrease agriculture
What methods have been developed to
successfully farm in areas of salinized
soil? Explain.
