PEO 3 Lecture Cards

Question 1

What specific kind of weathering causes the formation of a bare rock dome (such as Looking Glass Rock in the Blue Ridge Mountains of North Carolina, Caesar’s Head in South Carolina, or Halfdome in Yosemite National Park)?
And what types of rock usually occurs at those types of locations, as mentioned above?

Answer 1

Unloading (Also accepted: Sheeting and exfoliation). Granite.

Question 2

How many calories would it take to transform two grams of ice at -18C to water vapor at 104C?

Answer 2

9 + 80 + 100 + 540 + 2
731 per gram.
1467 calories.

Question 3

What type of mechanical weathering results from the volume increase (expansion) as water crystallizes to ice?

Answer 3

Frost expansion, when ice fills cracks and causes pressure, resulting in breakage.

Question 4

Where is the greatest amount of chemical weathering likely to occur?

Answer 4

In a wet tropical environment.

Question 5

At 0C, what % of molecules in liquid water are bonded?

Answer 5

80%

Question 6

Describe the arrangement (or draw a labeled drawing) of water molecules in ice?

Answer 6

Water is bonded hexagonally.

Question 7

Draw and fully label a visual drawing (cartoon) of a water molecule.

Answer 7

Two hydrogen atoms.
One oxygen atom.
105 degrees between the hydrogens.

Question 8

Which of these elements in crustal rocks is the least soluble? (Na, Ca, K, Fe, Al, Si, Mg)

Answer 8

Al

Question 9

Which type of chemical weathering is a dominant one affecting limestones?

Answer 9

Dissolution

Question 10

Which specific type of terrigenous sediment and/or sedimentary rocks represents the majority of such rocks?

Answer 10

Clay, shale, and mudstone are accepted answers.

Question 11

Gibbsite (bauzite) is the final hydrolysis weathering product of feldspar in hot wet climates. What resource do we get from bauxite?

Answer 11

Aluminum

Question 12

What is the form of chemical weathering in which the hydrogen in water in exchanged for metallic cations in minerals called?

Answer 12

Hydrolysis

Question 13

Which of the following is the least resistant to the effects of weathering? (quartz, amphibole, biotite, Na-feldspar, pyroxene)

Answer 13

Pyroxene

Question 14

Many of the ions produced by weathering and removed in solution in water may be reconstituted to form which type of sedimentary rock?

Answer 14

Limestone

Question 15

Name one of the three major categories of sedimentary rocks.

Answer 15

Accepted answers: Terrigenous, chamical, biogenic

Question 16

Name one of the environmental variables that influence the amount and rate of chemical weathering that will occur at a given locality.

Answer 16

One such answer is the slope/degree or incline/decline of a given location

Question 17

What aspect of water gives it such great solubility (dissolving) capacity? Explain.

Answer 17

It’s polar nature with 2- (oxygen) on one side and 2+ (hydrogen) on the other, allowing it to break ionic bonds easily.

Question 18

What aspect of water gives it its great thermal capacity?

Answer 18

Latent heat.

Question 19

Which type of chemical weathering is a dominant one affecting most metals?

Answer 19

Oxidation

Question 20

What dangerous and damaging byproduct results from oxidation of sulfide ores?

Answer 20

Sulfuric acid mine draining (H2SO4)

Question 21

What size material can be started into motion at the lowest threshold velocity?

Answer 21

Fine sand

Question 22

If the discharge of a river greatly increases, and the velocity rises slightly, what happens to the cross-sectional area, and what type of event occurs?

Answer 22

It increases, doubles the velocity, and then flooding occurs.

Question 23

How is sediment carried if a river is flower at a velocity greater than the settling velocity of the sediment?

Answer 23

The sediment is being suspended and carried.

Question 24

What is the term for the type of transport in which particles roll or slide along the bed of the river channel?

Answer 24

Partial suspension

Question 25

What is the river discharge formula?

Answer 25

Q = va

Question 26

A braided stream is one that recieves more sediment than the annual discharge can carry away. In what type of environment are such rivers most commonly developed?

Answer 26

In glacier regions

Question 27

True or False - The greatest velocity in a river is at the surface along the inside of a meander bend.

Answer 27

False.

Question 28

What is a sandy deposit on the inside of a river meander bend called?

Answer 28

Point bar

Question 29

Which river on Earth has the greatest annual discharge.

Answer 29

Amazon river

Question 30

With regard to a river, what does the term capacity refer to? (be precise)

Answer 30

The maximum amount of sediment a river could carry.

Question 31

Explain how incised river meanders form.

Answer 31

It begins as a mature river with a flat terrain, then tectonic uplift takes place.

Question 32

In what way does urbanization of a drainage area affect the timing and height of a river flood after a heavy rain event?

Answer 32

Flood occurs sooner and higher (flood is also shorter in duration).

Question 33

True or False - A highly meandering river is a relatively young river.

Answer 33

False.

Question 34

What happens to sediment being carried by a river when the flow velocity falls below the threshold and settling velocities of that size material?

Answer 34

They can no longer be suspended, and so they are deposited.

Question 35

Is a river with many nick points a young stream or an old stream?

Answer 35

Young stream

Question 36

Name a slow type of mass wasting.

Answer 36

Slump, solifluction, earth fall, rock fall

Question 37

If a river’s base level is raised, what happens to the competence of that river?

Answer 37

It decreases (Competence = The maximum size of particles that can be transported).

Question 38

The problems encountered when building the bridge from the Charleston Peninsula to James Island were the result of the Ashley River’s base level having been much _____ in the geologically recent past.

Answer 38

Lower

Question 39

Which type of mass wasting is the most dangerous and deadly?

Answer 39

Mudflow (Lahar, mud flow, debris flow– must be flow not slide).

Question 40

True or False - If the base level of a river rises, the river will erode (cut) a deeper channel.

Answer 40

False.

Question 41

Which would be the better purchase, a piece of property at the elevation of the 5-year flood recurrence interval, or one at the 25-year recurrence interval?

Answer 41

25-year recurrence interbal, though the flooding may be more sevre than the 5-year.