Section L - Weathering and Mass Wasting

What is geomorphology?

the study of the processes shaping earth’s surfaces and the landforms and deposits they produce

What is landform? (+ examples)

• specific natural physical features of the earth’s surface

  • mountains, valleys, hills, skull rock

what are landscapes?

• encompass the visible features of the area

  • view of San Andreas fault and valley from lookout in Joshua Tree

What is denudation?

disintegration (wearing away) and overall lowering of continental surfaces

Denudation involes which 3 activities?

• weathering

• mass wasting

• erosion

  • gravity, wind, water, ice, etc

The walls of Grand Canyon of the Colorado River are a result of the forces of _ and _

• weathering

• mass wasting

What is weathering (4)

• breakdown of rock in-situ (‘in place’)

  • physical, chemical, biological

What is mass wasting

• gravity, short distance

  • slop process

What is erosion?

• removal/ transportation

  • running water, glaciers, wind, coastal waves

What are the geomorphological agents? (5)

• gravity

• water

• glaciers

• wind

• waves

Weathering destroys _ and _ into smaller pieces

• bedrock

• fragments

Any exposed bedrock is _

weathered

What are joints?

• openings (typically microscopic) in surface allow weathering agents to transfer deeper into rock

  • water, air, plant root

Why are joints important?

Colder/ drier climates tend to have:

more physical weathering

Warmer/ wetter climates tend to have:

more chemical weathering

What is differential weathering?

some rocks are more resistant to weathering

What rock is more resistant to physical weathering?

limestone

What has variation in the cementing materials, leading to unusual landform where the rock weathers at different rates?

sandstone

What is caprock?

more resistant rock over less resistant rock

Mechanical (physical) weathering is: (3)

• physical disintegration of rock

• no change in its chemical composition

• increases surface area for chemical weathering

Type of physical weathering:

frost wedging/ shattering/ action

What is frost wedging? (4)

• process of freezing and thawing action of water

• ice wedges downward in openings

• ice melts and water falls farther into larger opening

• process repeats

What happens to water from the frost wedging process at 4-0 degrees C

water expands 9%

What is talus slope (scree)?

a pile of weathered rock that accumulates close to the mountain wall through numerous small rocks falls