9: Weathering and Mass Wasting Flashcards
(23 cards)
overall effect of the disintegration, wearing away, and removal of rock material.
occurs due to the interaction of three types of activities—weathering, mass wasting, and erosion.
Denudation
primarily responsible for producing variations in
the Earth’s ever-changing topography.
weathering, mass wasting, and erosion
cause rock to break down into smaller particles and to
decompose chemically at the Earth’s surface
weathering processes
breaking down of rock into smaller components by atmospheric
and biotic agents
Weathering
involves the relatively short-distance downslope movement of
broken rock material under the direct influence of gravity
Mass wasting
consists of the removal, transportation, and eventual deposition of
fragmented rock material over wider areas and sometimes to greater distances as
compared to mass wasting by an erosional agent.
Erosion
disintegration of rock into smaller fragments of the
same mineral composition by processes such as frost action, salt-crystal growth,
and unloading.
Physical weathering
decomposition of rock resulting from
mineral alteration processes such as hydrolysis, oxidation, and acid solution
Chemical weathering
weathered material covering the underlying bedrock
source of sediment carried by wind, water, and glacial ice, and the parent material for soil development.
regolith
one of the most important physical weathering processes in cold
climates.
occurs when water freezes in joints in the rock, and the expansion of
the water during repeated freezing forces the joints to enlarge
Frost action
operates extensively in dry climates and is the result of the growth of
salt crystals in rock pores.
Groundwater moves to the surface through capillary
action and evaporates, leaving the salts behind producing grain by grain breakup of sandstone
Salt crystal
weathering
form of physical weathering that occurs when the
removal of overlying layers causes the rock to expand, cracking in layers parallel to
the surface that break away from the rock in sheets
Unloading
occur when rocks are subject to intense heating and
cooling and through the growth of plant roots that can wedge rocks apart
Physical weathering
The chemical weathering processes of _____ change rock
minerals into clay minerals and oxides
hydrolysis and oxidation
most commonly due to the work of weak solutions of carbonic acid dissolving certain rocks, particularly
limestone and marble
Acid action
spontaneous downhill movement of soil, regolith, and rock on
slopes under the influence of gravity
Mass wasting
more susceptible to
mass wasting than bedrock.
Regolith and soil
gradual downhill movement of particles as they are rearranged by
wetting and drying, freezing, and thawing and other processes.
Soil creep
Water-saturated
regolith can move quickly down a slope in an ____
earthflow
develop when intense rains fall on exposed soil surfaces
Mudflows and debris
floods
A large mass
of bedrock which breaks free from a slope can slide rapidly downhill as a ____
landslide
can be induced both by natural processes
and by human activities
Earthflows, mudslides, and landslides
Human activities that extract mineral
resources involve ___ of the land surface.
scarification