Oceanography Chapter 10

What is the difference between weathering and erosion?

Weathering = breakdown of rock in place; Erosion = movement/transport of weathered material.

What is mechanical (physical) weathering?

The physical breakdown of rock into smaller pieces without changing its composition.

What is chemical weathering?

The breakdown of rock through chemical reactions that change mineral composition.

What is pressure-release fracturing?

Cracking as overlying rock is removed and pressure decreases.

What is frost wedging?

Water freezes in cracks, expands, and breaks the rock apart.

What is abrasion?

Rocks grind against each other, wearing down surfaces.

What is thermal expansion/contraction?

Repeated heating and cooling causes rock to expand and crack.

What is dissolution, and what does it often form?

Acidic water dissolves rock (especially limestone), forming caves.

What is hydrolysis?

Reaction with water; feldspar → clay, while quartz resists weathering.

What is oxidation?

Reaction with oxygen, causing “rusting” of iron-bearing minerals.

Give two examples of mechanical and chemical weathering working together.

Salt cracking and exfoliation

Why are many beaches made of quartz grains?

Quartz is highly resistant to chemical weathering.

What is regolith vs. soil?

Regolith = loose rock and mineral fragments; Soil = uppermost layer of regolith with organic matter, water, and gas.

What are the components of soil?

Mineral grains (clay, silt, sand, fragments), organic matter, water, and gas.

What are litter and humus?

Litter = freshly fallen organic material; Humus = decayed organic matter.

List the soil horizons (O, A, B, C) in order.

O = organic, A = topsoil, B = subsoil, C = partially weathered parent material.

Name five factors that influence soil formation.

Parent rock, climate, vegetation, slope/aspect, and time.

What is erosion?

The transport of weathered material by gravity, water, wind, or glaciers.

What is mass wasting? What factors cause it?

Downslope movement due to gravity; caused by steep slopes, rock type/orientation, loose material, vegetation loss, earthquakes, or volcanoes.

Name and distinguish the three main types of landslides.

• Flows: particles move independently (creep, debris flow, mudflow).

• Slides: material moves as a coherent mass (slump, rockslide).

• Falls: free fall from cliffs or steep slopes.

Name a form of physical weathering

frost wedging: when water enters cracks in rock, freezes, expands, and splits the rock apart