08 Weathering, Erosion, and Landscapes Free Online FlashCards

How do weathering, erosion, and deposition differ?

Weathering breaks down or changes rock in place; erosion removes and transports material; deposition is when transported material settles.

What happens during mechanical weathering?

Mechanical weathering breaks rock into smaller pieces without changing its minerals. Freezing water expanding in cracks is one example.

What is regolith?

Regolith is loose material formed from weathered rock. When it contains organic matter and supports plant growth, it is part of soil.

What is the difference between stream competence and capacity?

Competence is the largest particle a stream can move; capacity is the total amount of sediment it can carry.

How does an alluvial fan form?

An alluvial fan forms when a river leaves a steep, confined mountain valley and deposits sediment across flatter ground.

What happens to sediment as moving water slows?

As flow slows, larger grains tend to settle before finer particles.

How do deflation and abrasion differ?

Deflation lifts or removes loose particles. Abrasion occurs when windblown sand grains strike and wear rock.

What is loess?

Loess is a deposit of windblown silt.

How can a valley glacier reshape a river valley?

Valley glaciers can widen and deepen river valleys, changing their V-shaped profiles into broad U-shaped valleys.

What are till and moraines?

Till is a mixture of sediment sizes deposited by melting ice. A moraine is a ridge of glacial sediment.

What is mass wasting, and what can destabilize a slope?

Mass wasting is the downslope movement of material under gravity. Rain or snowmelt can saturate and destabilize a slope; stream erosion can undercut its base.

What is a debris flow, and why is it hazardous?

A debris flow is a fast-moving mixture of water and sediment, sometimes including boulders. It can bury or damage places in its path.