Weathering and Erosion Flashcards

Flashcards covering key concepts from a lecture on weathering and erosion, including types of weathering, factors affecting weathering rates, erosion processes, and human impact.

What human activities have moved more sediment in recent years than running water?

Road-building, livestock overgrazing, deforestation, construction projects, mining and urbanization, and poor farming methods.

What do many scientists believe significant human activity on Earth has created?

A new part of geologic time called the Anthropocene.

What is abrasion?

Abrasion is physical weathering that occurs when rock particles grind against rock.

What is the chemical and physical breakdown of rocks at or near Earth's surface called?

Weathering

What is chemical weathering?

The breakdown of rock through a change in mineral or chemical composition.

What is physical weathering?

The breakdown of rock into smaller pieces without chemical change.

How does frost action break up rocks?

Water trapped in cracks freezes and expands, enlarging the cracks. After many cycles of freezing and thawing, the rock crumbles.

How does decreased pressure lead to physical weathering?

When the pressure on rocks is reduced, the rocks expand and crack.

How does particle size affect the rate of weathering?

Smaller rock particles have a greater surface area per unit volume exposed to weathering, therefore weathering is faster.

How does mineral composition affect the rate of weathering?

Different minerals have different physical and chemical properties which affects the rate of weathering.

In what type of climate is chemical weathering most pronounced?

Warm, moist climates.

What are the components of soil?

A mixture of rock particles and organic matter on Earth's surface that supports rooted plants.

What is humus?

A part of soil that serves as a source of plant nutrients and is formed by dead leaves and remains of other living things.

What is the difference between chemical and physical weathering?

Chemical weathering alters the composition of minerals, and physical weathering does not.

What is the driving force for most types of erosion?

Gravity

What is mass movement?

When gravity acts largely on its own by pulling rocks and sediments downhill.

What is running water erosion?

Running water erosion is often considered the most common natural agent of erosion on Earth's solid surface.

What is a stream?

A smaller stream that flows into a larger stream is called a tributary.

What are the three factors that are most important in determining the average velocity of a stream?

The gradient, or slope of the stream. The discharge, or volume of water in the stream. The stream channel shape.

What is a finger lake?

Finger lakes are bodies of water in U-shaped valleys carved by glaciers often partly dammed at one end by a pile of glacially-deposited sediments.

What are the two main aspects to wind erosion?

Deflation and sandblasting or abrasion

What is a glacier?

A naturally formed mass of ice and snow that moves downhill on land under the influence of gravity.

What do wave and current erosion create?

Unique landscape features where lake or ocean waters meet land.