Lecture 17: Weathering and Mass Movements

Question 1

______ are processes that operate on or near the Earths surface (e.g. glaciation, coastal waves, river erosion)

Answer 1

Exogenic

Question 2

What is the energy that drives exogenic processes?

Answer 2

solar radiation

Question 3

______ are processes that operate in the subsurface but can influence the Earth surface (e.g. volcanic and seismic activity).

Answer 3

Endogeneic

Question 4

What is the energy that drives endogenic processes?

Answer 4

internal geothermal heat from radioactive decay elements, drives plate tectonics

Question 5

_____ is the set processes that act to break down materials (bedrock) at the surface and in the shallow subsurface.

Answer 5

Weathering

Question 6

_______ is produced from the partial fracturingand decomposition of bedrock.

Answer 6

Regolith

Question 7

What are the 3 types of weathering processes?

Answer 7

Physical, chemical, biological (organic)

Question 8

What are the three types of physical weathering processes?

Answer 8

Freeze-thaw (freezing of water in pores and openings in sediment and rock causes the formation of ice)

Salt crystal growth (Evaporation of highly saline water from pores and openings in rock or sediment can produce a supersaturated solution, from which salt crystals precipitate)

Pressure release (Expansion of rock that results from the removal of overlying sediments and rock (e.g. by erosion) or the removal of an overlying glacial ice mass)

Question 9

What are the 4 types of chemical weathering processes?

Answer 9

Solution, Carbonation, Hydrolysis, Oxidation

Question 10

True or False: in chemical reactions, several chemical reactions can occur, reactions are more effective at high temperature, low pH, and under moist conditions, materials that are produced are more stable than the original substances

Answer 10

True

Question 11

True or False: Physical weathering occurs in places where there is little soil and few plants to grow.

Answer 11

True

Question 12

_____ is a slow to very rapid downslope motion of soil, sediment and or rock from high to low elevation.

Answer 12

Mass movement

Question 13

What are the 3 functions of slope stability?

Answer 13

(i) the materials that comprise the slope,
(ii) the gradient of the slope, and
(iii) the moisture content of the materials.

Question 14

What are 5 types of mass movements?

Answer 14

Falls
Topples
Slides
Flows
Complex

Question 15

_____ motion is achieved by internal shearing within the flowing mass (similar to fluidflow).

Answer 15

Flow

Question 16

______failures display more than one type of motion. For example, large rockslides can behave like flows and spread across large areas (called a Rock Avalanche)

Answer 16

Complex

Question 17

_____ is the detachment and downslope motion of a mass of rock or sediment along a well defined failure surface. The failure surface may be a bedding plane, fault, fracture or other discontinuity, the surface may be a plane or curve

Answer 17

Slides

Question 18

____ are the forward rotation of a cohesive block of rock, failure occurs along well developed joints or bedding planes.

Answer 18

Topple

Question 19

_____ detachment of blocks from steep surfaces

Answer 19

Falls

Question 20

What are the 3 ways mass movement occurs?

Answer 20

(i) moisture (Rain or Snowmelt),
(ii) seismic shock, and
(iii) undercutting