Geology Exam #2 A05

Which of the factors listed below does not influence the rate of chemical weathering?

Mass of rock available

In what way does the amount of mechanical weathering that has taken place influence the rate at which chemical weathering occurs?

Mechanical weathering increases the surface area exposed to chemical weathering.

In the silicate minerals there is a correlation between chemical weathering and Bowen's Reaction Series. What is the relationship?

Silicate minerals that form at the highest temperatures are most susceptible to chemical weathering.

In many older cemeteries you can often find headstones made of slate. In viewing these headstones today the lettering is as sharp and clear as the day it was cut. However many marble headstone inscriptions are illegible. What property of slate allows it to survive the test of time?

Clay minerals in the slate make it extremely resistant to weathering.

Of the following which is not an example of Earth's external processes and/or external process-driven phenomena?

Volcanoes

All modification of Earth's outer surface is initiated by which of the following processes?

Weathering

Of the responses provided which is the predominant source of energy for most external processes that operate on Earth?

The sun

Earth's surface is subjected to unusually high rates of weathering. The Moon and some of the inner planets of our solar system are also subject to surface weathering but at much slower rates. Which of the following statements most reasonably explains Earth's uniquely rapid weathering rates?

Earth has running water at the surface

Once weathering begins and particles are produced which factor is most influential in moving them around Earth's surface?

Gravity

Of the following types of mass wasting which tends to be the fastest moving and most destructive?

Rockslides

Which of the following examples of mass wasting is characterized by a crescent-shaped scarp or cliff at its head?

Slump

Which of the following types of mass wasting is extremely slow and occurs when saturated soil flows downslope?

Solidification

At a local landfill the liner beneath the trash was being repaired. In the process trash from the base of the slope was removed and piled on top of the landfill. After an unusually heavy rainfall the slope failed very quickly along a curved surface. Which of the following types of mass wasting best describes this slope failure?

Slump

During the eruption of Mount St. Helens on May 18 1980 snow and glacial ice on the mountain melted and rushed down the Toutle River. What is the name given to this specific type of mass wasting?

Lahar

What is the definition of physical weathering?

Mechanical processes break substances into smaller pieces.

Using the picture of the Entrada Sandstone in Figure 1 try to identify the evidence of physical and/or chemical weathering present.

Rusty color and fracturing

Which of the three images in Figure 2 would be most susceptible to chemical weathering and why?

C: physical weathering has created more surface area for chemical weathering to attack

Which of the following is an example of chemical weathering?

A car fender getting rusty

How does physical weathering cause chemical weathering to be more effective?

When a rock is physically broken into smaller pieces there is more surface area on which chemical weathering can occur.

Triggered by curved over steepened slopes

slump

Triggered by large amounts of water and steep slopes

Flow

Triggered by repeated freezing and thawing of soils on gentle slopes

Creep

Triggered by ice wedging or plant activity on steep slopes

Fall

Creep is _____.

Mass wasting by a gradual downhill movement of sediment, influenced by freeze-thaw or wet-dry cycles

Describe how a soil particle moves downhill during the freeze-thaw process.

During the freeze, a soil particle moves at a right angle away from the surface, and thawing causes the particle to fall back to a slightly lower level.

Why would trees be j-shaped?

The trunks become tilted in the downhill direction due to creep, but continue to grow toward the sun

Which of the following is associated with creep?

Slow and subtle movement of material

A _______ is a common result of creep.

Broken retaining wall