Weathering

Question 1

The expansive force of accumulation of crystal growth of salt after evaporation of sea water enlarges cracks and pore spaces within the rock. Which type of weathering was explained?

Answer 1

Mechanical weathering

Question 2

Which is responsible for the formation of rust when specific element dissolved in water reacts with iron present in rocks?

Answer 2

Oxidation

Question 3

Unloading refers to the removal of the overlying burden of rock therefore allowing the intrusive igneous rocks to expand. Which will result from this process of weathering?

Answer 3

Sheeting

Question 4

Mechanical and chemical weathering reinforce each other and work simultaneously in nature. Which of the following processes shows how chemical weathering aids mechanical weathering?

Answer 4

Spheroidal weathering

Question 5

Weathering occurs when rocks are mechanically fragmented and/or chemically altered. Which of the following is a process involving mechanical weathering?

#Oxidation
#Exfoliation
#Carbonation
#Hydration

Answer 5

Exfoliation

Question 6

Which is NOT a process involved in mechanical weathering?

#Frost wedging 
#Salt crustal growth  
#Exfoliation and sheeting 
#Oxidation

Answer 6

Oxidation

Question 7

Which of the following refers to the removal of overlying burden of rocks which reduces the confining pressure and causes rock to expand more separate from the rock body?

Answer 7

Unloading

Question 8

Which is the primary force of weathering?

Answer 8

Water

Question 9

Which occurs when water moves into empty pores or spaces of rock by capillary action,
evaporates and leave salt crystals?

Answer 9

Salt Crystal Growth

Question 10

Which is an example of a biological activity that results to weathering?

Answer 10

Burrowing

Question 11

The physical and chemical processes that break down rock on earth’s surface.

Answer 11

Weathering

Question 12

Functions of Weathering?

Answer 12

▪ Gives rock lower strength and greater permeability, rendering it more susceptible to mass wasting and erosion;
▪ Produces minor landforms in soluble rock (especially limestone)
▪ Releases minerals in solution (e.g. iron oxides, silica, carbonates, etc)
▪ First step in soil formation

Question 13

Two Types of Weathering

Answer 13

Mechanical and Chemical Weathering

Question 14

Mechanical Weathering (aka Physical Weathering)

Answer 14

• Physical Change had occurred
• Surface Area had increased
• Rocks were cut into smaller pieces

Question 15

Main Sources of Mechanical Weathering

Answer 15

• Water
• Gravity
• Wind
• Waves

Question 16

Explain Chemical Weathering

Answer 16

• Chemical change occurs changing the chemical composition of a particular rock.
• The products of chemical weathering will remain essentially unchanged as long as they remain in an environment similar to the one in which they formed.

Question 17

Different Types of Mechanical Weathering

Answer 17

• Frost Wedging
• Salt Crystal Growth
• Sheeting
• Biological Activity

Question 18

Explain Frost Wedging

Answer 18

Frost wedging occurs when the water freezes expanding its self up to 9 percent.

• the water goes inside the crevices of the rocks and freezes therefore breaking the rock.

Question 19

Explain Salt Crystal Growth

Answer 19

When the sea sprays to the pore spaces of the rocks. Over time, the water evaporates leaving the salt alone. As these crystals grow bigger, they weaken the rock by pushing apart surrounding grains or enlarging tiny rocks.

Question 20

Where does SCG occur commonly?

Answer 20

Rocky Shorelines and Arid Regions

Question 21

Explain Sheeting and the connection between Unloading

Answer 21

• A massive igneous rock is formed deep within the surface where the confining pressure is great.
• Erosion removes the surface revealing the igneous rock (Unloading).
• Joints form parallel to the surface then continues to break down causing slabs to separate and fall off.
• Exfoliation and Sheeting happen as a result of sheeting

Question 22

Explain Biological Activity under MW

Answer 22

• The activities of organisms, including plants, burrowing animals, and humans can cause weathering. Plant roots in search of minerals and water grow into fractures, and as the roots grow, they wedge the rock apart.
• Plants and Animals also contribute to this type of weathering.

Question 23

Different types of Chemical Weathering

Answer 23

• Hydrolysis
• Carbonation
• Oxidation
• Hydration

Question 24

What type of CW happens when water changes the chemical composition of the rock?

Answer 24

Hydrolysis

Question 25

How does Hydrolysis happen?

Answer 25

When Hydrogen ions replace some ions making them less resistant to weathering.

Question 26

Explain Carbonation

Answer 26

• CO2 combined with H2O will create H2CO3 (Carbonic Acid), the acid ionizes to form a very reactive Hydrogen Ion and bicarbonate ion.
• The Carbonic Acid decomposes many rocks rocks and produce products that are water soluble.

Question 27

Stalactites are known for what CW?

Answer 27

Carbonation

Question 28

What is Oxidation?

Answer 28

When H2O is oxidized by O2, this will produce FeO2 with the color yellow to reddish brown.

Question 29

How is Hydration different from Carbonation?

Answer 29

Carbonation occurs when CO2 mix with H2O while Hydration occurs when H2O is absorbed into the mineral source. For instance, if rock rich with potassium feldspar is exposed in water, dissolution will turn this mineral to clay.

Question 30

What things affect the rate of weathering?

Answer 30

• Rock Characteristics
• Climate
• Differential Weathering

Question 31

Explain Spheroidal weathering

Answer 31

• Process of producing rocks with spherical shape through both chemical and mechanical weathering. It shows how chemical weathering aids mechanical weathering by weakening the rocks from the inside, making it more susceptible to physical attack.
• Water comes to the rock (Hydrolysis), Various factors attack the rock (MW) making them spheroidal rocks.