Weathering, Soil, and Mass Wasting Flashcards

mass wasting process
Terms Definitions
Earth's External Processes
at the surface, responsible for transforming solid rock into sediment, process: weathering, mass wasting, erosion
weathering
the disintegration and decomposition of material at or near the surface, mechanical or chemical
mass wasting
the transfer of rock material downslope under the influence of gravity
erosion
the incorporation and transportation of material by a mobile agent, usually water, wind, or ice
mechanical weathering
breaking rock into smaller pieces through frost wedging, unloading, biological activity
Frost wedging
wet climate, cool water freezes, water will get into small cracks and freezes and expands,temp increases, water thaws, repeat, bust and move the rock, occurs in NE climate
chemical weathering
alters the internal structures of minerals by removing or adding elements, most important agent is water
rates of weathering
surface area increase advances weathering, important factors: rock characteristics, climate, and differential weathering
rates of weathering: rock characteristics
mineral composition, solubility, physical features such as joints
rates of weathering: climate
temperature and moisture, chemical weathering is the most effective in areas of warm temperatures and abundant moisture
rates of weathering: differential weathering
caused by variations in compositions, creates unusual and spectacular rock formations, west the wind is going to do the damage`
difference between chemical and physical weathering
chemical leaves odd shapes because of the way the acids eat away
joint-controlled weathering in igneous rock
crack because of force and frost wedging opens up the joints
soil
interface in earth's system, combination of mineral matter, water and air, final product of weathering
soil classification: texture
refers to the proportions of different particle sizes sand, silt, clay, loam
loam
a mixture of all three sizes of particles , best suited for plant life
soil classification: structure
soil particles clumped to give a soil its structure, helps determine a soils porosity and permeability, platy, prismatic, blocky, spheroidal
controls of soil formation
parent material, time, climate, plants and animals, slope
controls of soil: residual soil
parent material of the soil (bedrock)
controls of soil:transported soil
parent material has been carried from eleswhere and depositied ex: buying pot soil or water carrying sediments
control of soil: time
important in all geologic processes (nothing happens fast), amount of time to evolve varies for different soil
control of soil: climate
needs water
control of soil: plants and animals
organisms influence the soils physical and chemical properties and furnish organic matter to soil
control of soil: slope
steep slopes often have poorly developed soils because of water run off, the direction the slope is facing
soil profile
soil forming process operates from the surface downward
horizons
zones or layers of soil
soil profile: topsoil
organic matter and mineral matter
soil types
pedalfer, pedocal, and laterite
soil types: pedalfer ( 2 example)
alumunin, iron, best developed under the forest region (NW forest regions, Borreal forest
soil types: pedocal ( 2 example)
oxygen, calcium, dry grasslands (Africa and MW grain belt)
soil types: laterite
hot, wet, tropical climates, rain forest, intense chemical weathering
soil erosion
recycling of earths material, can cause reservoirs to fill with sediments
natural rates of soil erosion
soil characteristics, climate, slope, type of vegetation
secondary enrichment
concentrates metals into economical deposits
process of secondary enrichment
removing undesired material from decomposing rock leaving the desired materials behind, desired elements are carried to lower zones and deposited
mass wasting
the downslope movement of the rock, regolith, and soil under the direct influence of gravity, gravity is controlling force
mass wasting triggering factors
saturation of the material with water, over steeping of slopes, removal of anchoring vegetation, and ground vibrations from earthquakes
types of mass wasting process
the material involved: debris, mud, earth, or rock, the movement of the material: fall, slide, flow
types of mass wasting process
slump, rock slide, mud flow, earth flow, liquefaction, creep, solifluction
types of mass wasting process: slump
rapid movement along curved surface, occurs along over steepened slopes
types of mass wasting process: rock slide
rapid, blocks of bedrock move down a slope
types of mass wasting process: mud flow
rapid flow of debris with water, often confined to channels, serious problem in dry areas with heavy rains
lahar
debris flows composed mostly of volcanic materials
types of mass wasting process: earth flow
rapid, typically occur on hillside in humid regions, water saturate the soil
types of mass wasting process: liquefaction
a special type of earth flow sometime associated with earthquakes
types of mass wasting process: creep
slow movement of soil and regolith downhill, cause fences and utilty poles to tilt
types of mass wasting process: solifuction
slow movement in areas by permafrost, upper (active) soil layer becomes saturated and slowly flows over a frozen surface below
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