Geology: Exogenic Processes

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Questions and Answers

Which of the following is a human activity that contributes to physical weathering?

Oxidation of iron-rich rocks

Carbonation of rocks

Digging and quarrying (correct)

Burrowing by animals

What is hydrolysis in the context of chemical weathering?

Dissolving minerals in carbonic acid

The movement of rock particles through erosion

Rusting of iron-rich minerals in rocks

Breaking down rocks by acidic water to form clay (correct)

Which process involves oxygen reacting with minerals to cause weathering?

Hydrolysis

Dissolution

Oxidation (correct)

Carbonation

What role does running water play in erosion?

It transports sediment effectively based on water volume. (C) Signup and view all the answers

Which of the following can result from carbonation weathering?

Formation of limestone pavements (C) Signup and view all the answers

Which animals are known to cause physical weathering by burrowing?

Rats and rabbits (C) Signup and view all the answers

What is the primary agent of erosion among the listed options?

Water (D) Signup and view all the answers

What is a result of the process of erosion?

Movement of rock particles away from their source. (B) Signup and view all the answers

What is the primary difference between physical weathering and chemical weathering?

Physical weathering involves disintegration, while chemical weathering involves decomposition. (C) Signup and view all the answers

Which of the following is NOT a factor that causes physical weathering?

Chemical reactions (C) Signup and view all the answers

How does frost wedging contribute to physical weathering?

By causing ice to expand within rock fractures, breaking them apart. (D) Signup and view all the answers

What role does organic activity play in physical weathering?

It contributes to the breakdown of rocks through root penetration. (C) Signup and view all the answers

Which statement best describes the process of abrasion in the context of physical weathering?

Rocks are worn down by the impact and friction from other materials. (B) Signup and view all the answers

What effect does thermal and pressure change have on rocks?

It can cause rocks to crumble and break into fragments. (D) Signup and view all the answers

What is the main result of the agents of weathering, erosion, and deposition?

They transform types of rocks in the Earth's crust. (B) Signup and view all the answers

How does temperature variation contribute to physical weathering?

By causing repetitive expansion and contraction of rocks. (B) Signup and view all the answers

What is the primary force that causes mass movement in slope areas?

Earth's gravitational force (D) Signup and view all the answers

Which type of mass wasting involves the slow downhill flow of soil?

Solifluction (B) Signup and view all the answers

What distinguishes debris flow from other types of mass wasting?

It contains a mixture of loose mud, sand, soil, rock, water, and air. (D) Signup and view all the answers

Which type of mass wasting is characterized by rapid sliding of coherent materials along a curved surface?

Slump (D) Signup and view all the answers

What process is involved in the erosion caused by glaciers?

Carving out deep valleys (D) Signup and view all the answers

In which scenario would a mudflow likely occur?

After continuous heavy rain (D) Signup and view all the answers

What is the defining characteristic of soil creep?

It is a slow, gradual movement of soil downhill. (B) Signup and view all the answers

Which type of erosion is described as carrying dust, sand, and volcanic ash from one location to another?

Wind erosion (C) Signup and view all the answers

Study Notes

Exogenic Processes

Exogenic processes modify the Earth's surface, causing degradation and sculpting the landscape.
Key types include weathering, erosion, mass movement (mass wasting), deposition, and sedimentation.

Weathering

Weathering involves the disintegration (physical) and decomposition (chemical) of rocks.
Types of weathering are classified into physical and chemical categories.

Physical Weathering

Rocks break into smaller pieces without changing composition through physical weathering.
Factors causing physical weathering:
- Thermal and Pressure Change: Rock expands when heated and contracts when cooled, leading to crumbling.
- Temperature: High temperatures cause expansion, while freezing can also fracture rocks.
- Frost Wedging: Water enters cracks in rocks, freezes, and expands, causing further breakage.
- Abrasion: Friction and impact from moving particles like sand and silt shape rocks by wearing down sharp edges.
- Organic Activity: Plant roots can penetrate cracks and expand, leading to rock breakage.
- Human Activities: Actions such as digging, quarrying, and deforestation contribute to physical changes in rocks.
- Burrowing Animals: Animals like rats and rabbits excavate ground, altering soil and rock structures.

Chemical Weathering

Causes decomposition of rocks through chemical reactions altering rock-forming minerals.
Factors causing chemical weathering:
- Dissolution: Rock minerals dissolve in water, altering structure.
- Hydrolysis: Acidic water breaks down minerals into clay and soluble salts.
- Carbonation: Carbon dioxide combines with water to form carbonic acid, leading to weathering of limestone and formation of stalactites.
- Oxidation: Oxygen and water react with minerals (e.g., iron-rich rocks), causing rusting and surface decomposition.

Erosion

Involves the movement of rock particles by agents such as wind, water, ice, and gravity.
Agents of erosion: Water, wind, ice, and gravity significantly impact landscape alteration.
Running Water: The most powerful erosive force, reshaping landscapes by transporting sediments during heavy rains and floods.
Wind: Carries sand and dust, particularly in arid regions, forming dunes and landscapes via erosion.
Ice: Glaciers erode landscapes by picking up and transporting materials as they move.

Mass Movement

Involves the downhill movement of soil and rock debris influenced by gravity.
Types of mass wasting processes include slump, solifluction, earthflow, mudflow, debris slide, debris flow, rock flow, and soil creep.
Slump: Sliding of cohesive materials along a curved surface.
Solifluction: Slow downhill flow of saturated soil.
Earthflow: Viscous flow of fine-grained materials saturated with water.
Mudflow: Rapid movement of mud down slopes.
Debris Slide: Chaotic movement of mixed materials down slopes.
Debris Flow: Loose materials traveling downhill under gravity.
Rock Fall: Detachment of rocks from steep cliffs.
Soil Creep: Gradual, slow movement of soil over time.

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Description

This quiz covers the concepts of weathering, erosion, and deposition as exogenic processes. You will learn how these processes occur and identify the agents responsible for them. Test your understanding of how these forces shape and transform Earth's crust.