Weathering Part 2 Ch. 8

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 statements is associated with chemical weathering?

Chemical weathering changes the chemical composition of the rock.

__________ is when various geologic materials exposed to the same environmental conditions will weather differently depending on their composition.

Differential weather

Which of the following factors does NOT affect the rate of chemical weathering?

Erosion

Which of the following statements regarding weathering and erosion is NOT true?

Erosion and weathering have the same definition and can be used interchangeably.

All of the following are factors that affect rates of weathering except for ________.

Geologic age of earth materials

The major determining factor for the chemical break down of rocks is their chemical composition. For example, granite and basalt are both igneous rocks with different chemical composition and structure and, therefore, different weathering rates. Rocks with minerals that crystallize late in Bowen's reaction series, like granite, are usually more resistant to chemical weathering than those with minerals that crystallize early, like basalt.Besides chemical composition, a secondary factor that affects the rate of weathering in such rocks is the amount of cracks/fractures present.Rank the rocks in order of the rate of chemical weathering they would experience, assuming they are all located in the same warm wet climate.Rank from slowest to fastest.

Granite, with very few or no cracks -> Granite, with abundant cracks-> Basalt with few to no cracks-> Basalt with abundant vesicles (holes)

Which of the following locations will weather a block of marble the most quickly?

Honolulu, Hawaii

What is the definition of physical weathering?

Mechanical processes break substances into smaller pieces.

Read the following descriptions of several different environments. Based on the information given, sort each environment into the correct bin for an environment that would experience predominantly mechanical weathering or predominantly chemical weathering.Drag the appropriate items into their respective bins.

Mechanical weathering would predominate: A cold wet environment at high elevation, in which freezing and thawing is common. A cold dry environment experiencing uplift, in which material is being removed by erosion from an underlying pluton/intrusive igneous rock. Chemical weathering would predominate. A hot environment with many short but intense rainstorms. A hot humid climate with heavy precipitation that occurs all year. A warm wet environment with above-average yearly rainfall and several stormy seasons each year.

Under similar warm, moist climatic conditions, why would basalt and gabbro generally have higher chemical weathering rates than rhyolite and granite?

The ferromagnesian minerals in the gabbro and basalt are subject to oxidation and chemical breakdown. Submit

Both tombstones in Figure 1 are from the same cemetery and were erected within four years of each other. Why is the younger marble tombstone more weathered than the older granite tombstone?

The quartz and feldspars in the granite are more resistant to weathering than the calcite in the marble.

During the late Cretaceous, the Bisti Badlands were home to numerous animals including turtles, crocodiles, and even dinosaurs. What type of environment were they living in?

They were living along rivers and deltas on the edge of an inland sea.

Which of the following climates will have the highest rate of weathering?

Warm, wet climates

What two factors speed up rates of chemical reaction and weathering in rocks and soils?

What two factors speed up rates of chemical reaction and weathering in rocks and soils? Warm temperatures, very moist

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.

Which of the following is an example of chemical weathering?

a car fender getting rusty

Clay minerals formed from gabbro or diorite bedrock illustrate which kind of weathering?

chemical

A hoodoo with a cap rock of sandstone and shale below is an example of __________.

differential weathering

Features like rock ledges in badlands or rock fins standing above adjacent valleys are all examples of ________.

differential weathering

Chemical weathering rates are highest in ________.

hot and wet climates

Limestone and marble weather faster than granite because ________.

limestone and marble can be dissolved by weak acids in rain

One important relationship between chemical and mechanical weathering is ________.

mechanical weathering can produce smaller pieces of rock that have more surface area for chemical weathering to work on.

The finely divided, red, brown, and yellow soil-coloring minerals originate by what process?

precipitation of iron oxides during the chemical weathering process

Which of the following is most resistant to both chemical and physical weathering?

quartz

Which one of the following is NOT an example of a mechanical weathering process?

reactions that occur when rain mixes with carbon dioxide to form carbonic acid

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

rust-colored sandstone