Weathering, Karst Landscapes, & Mass Movement Flashcards

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1
Q

What is denudation?

A

the process in which landforms are worn away and rearranged

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2
Q

What is weathering?

A

the breakdown of rocks

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3
Q

What is mass movement?

A

the movement of surface material

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4
Q

What is erosion?

A

the transportation of material to different locations

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5
Q

What is slope?

A

any inclined surface

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6
Q

How does the weathering of rock on a slope effect material?

A

loosens material for erosion

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7
Q

What three forces must be overcome before the movement of material can occur?

A
  • frictional resistance
  • inertia
  • cohesion
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8
Q

What is the angle of repose (4)?

A
  • the maximum incline at which material can remain at rest before gravity begins to pull it downslope
  • normal angle 33-37 degrees
  • smaller particles have a more shallow angle
  • larger particles have a steeper angle
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9
Q

What is the difference between a stable and unstable slope?

A
  • stable: the strength of the slope exceeds the force of gravity
  • unstable: the strength of the slope does not exceed the force of gravity
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10
Q

What is the difference between bedrock and regolith?

A
  • bedrock: the parent rock from which regolith and soil develop
  • regolith: unconsolidated rocky material covering the bedrock
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11
Q

What is physical weathering and what does it do?

A
  • breaks down rock without chemical alteration

- creates cracks which facilitate chemical weathering

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12
Q

What are the three types of physical weathering?

A
  • frost action: water gets between cracks in the rock and expands, breaking it apart
  • salt crystal growth: moisture inside the rock evaporates, leaving dissolved mineral solts behind which crystallize, grow, and break the rock apart
  • pressure release jointing: plutons created below the surface respond to a decrease in pressure above the surface by breaking into sheets
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13
Q

What are the four types of chemical weathering?

A
  • hydration: water permeates rock and becomes part of the chemical composition of the rock; rock breaks apart when water evaporates
  • hydrolosis: chemical reaction occurs when water permeates rock
  • oxidation: certain metallic elements in the rock combine with oxygen to form oxides
  • carbonation: occurs when water vapor dissolves carbon dioxide, forming carbonic acid, which dissolves many minerals; made worse by human activity
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14
Q

What is differential weathering?

A

process in which rock formations weather at different rates

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15
Q

What are the five factors that influence weathering?

A
  • rock composition and structure
  • climate
  • slope orientation
  • subsurface water
  • vegetation
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16
Q

How does rock composition and structure influence weathering (3)?

A
  • rock characteristics
  • mineral composition
  • presence of joints
17
Q

How does climate influence weathering (3)?

A
  • warm/wet climates cause chemical weathering to occur faster
  • high latitude climates likely to experience frost action
  • the same rock type in different climates experiences different rates of weathering
18
Q

How does slope orientation influence weathering (3)?

A
  • north/south facing impacts sunlight
  • north-facing slopes cooler and wetter; more vegetation
  • south-facing slopes warmer and drier; less vegetation
19
Q

How does subsurface water influence weathering (2)?

A
  • height of water table

- movement/percolation of water

20
Q

How does vegetation influence weather?

A

can prevent weathering (shields regolith/bedrock from water) or promote weathering (releases organic acids and roots break rock apart)

21
Q

What is mass movement?

A

the movement of any surface material downslope

22
Q

What are the three characteristics of mass movement?

A
  • moisture
  • particle size
  • speed
23
Q

What is the significance of slope (3)?

A
  • mass movement only occurs on sloped surfaces
  • mass movement only occurs when slope exceeds angle of repose
  • different materials result in higher/lower likelihood of mass movement
24
Q

What are the the two mechanisms that trigger mass movement?

A
  • water: as saturation increases, mass movement increases

- geomorphic threshold: the failure point of a slope

25
Q

What are the four types of mass movement?

A
  • falls/avalanches: rockfalls and debris avalanches; fastest type; no moisture
  • landslides: sudden, cohesive mass movement of regolith and bedrock; faster type; no moisture
  • flows: earthflows, mudflows, and debris flows; slower type; moisture
  • creep: the persistent and gradual downward movement of soil; slowest type; moisture
26
Q

What is karst topography and what does it look like (4)?

A
  • common in areas with limestone rock: calcium carbonate dissolves in water
  • irregular, pitted surface
  • poor surface drainage and cavern formation
  • originated from Krs Plateau in Slovenia
27
Q

Where are karst formations located in the U.S. (4)?

A
  • central Florida
  • central Texas
  • Shenandoah, Virginia
  • Mammoth Cave, Kentucky
28
Q

What are the four conditions required for karst topography to form?

A
  • limestone rock which contains at least 8% calcium carbonate
  • joint pattern: cracks which allow water to drain inward
  • zone of air between ground surface and water table
  • vegetation to supply organic acids to enhance dissolving process
29
Q

What are the three features of karst landscapes?

A
  • sinkholes: circular depressions
  • limestone towers: blocks of limestone resistant to erosion
  • caverns: caves formed within limestone rock
30
Q

What are seven features which can occur in caverns?

A
  • column
  • drip curtain
  • rock fall
  • sinkhole
  • solution pipe
  • stalactites (ceiling)
  • stalagmites (ground)