Lesson 5 - Weathering,soil, & Mass Wasting Flashcards
What are earths three external process?
Weathering
Mass wasting
Erosion
What is the disintegration and decomposition of material at or near the surface?
Weathering
What is the transfer of rock material downslope under the influence of gravity?
Mass wasting
What is the incorporation and transportation of material by a mobile agent , usually water, wind, or ice?
Erosion
What are the two kinds of weathering?
Mechanical
Chemical
What is mechanical weathering?
Breaking rocks into smaller pieces?
What is chemical weathering?
Altering the internal structures of minerals by removing or adding elements
What are the four processes of mechanical weathering?
Frost wedging
Unloading
Biological activity
What is the most important agent in chemical weathering?
Water
(Chemical weathering) what does the oxygen dissolved in water do?
Oxidizes material
(Chemical weathering) What does carbon dioxide dissolved in water do?
Forms carbonic acid and alters the material
What does the weathering of potassium feldspars produce?
Clay materials
Soluble salt (potassium bicarbonate)
Silica in solutions
What remains substantially unaltered during the chemical weathering of granite?
Quartz
What is produced when silicate materials are weathered?
Soluble sodium, calcium, potassium, and magnesium products
Insoluble iron
Clay materials
How can chemical weathering also produce physical changes?
Spheroidal weathering
How does mechanical weathering aid chemical weathering ?
By increasing the surface area
What are important factors of weathering rates?
Rock characteristics
Climate
What two rock characteristics are factors in the rate of weathering?
Mineral composition and solubility
Physical features
What mineral composition dissolved in weakly acidic solutions?
Marble (calcite)
In what order do silicate minerals weather in?
The order of their crystallization
What physical features example os a factor of weathering rate?
Joints
What are the two most crucial factors of climate that influence the rate of weathering?
Temperature
Moisture
What climate is chemical weathering most effective?
Warm temperatures
Abundant moisture
What is differential weathering caused by?
Variations in compositions
What is created by differential weathering?
Unusual and spectacular rock formations and landforms
Freeze wedging is caused by the repeated freeze-thaw.
Frost wedging
The removal of great weights of rock or ice that lie on the surface. This may happen through rising temperatures that melt ice sheets; erosion by wind, water or ice; or tectonic uplift.
Unloading weathering
The weakening and subsequent disintegration of rock by plants, animals and microbes. Growing plant roots can exert stress or pressure on rock
Biological activity weathering
What occurs in the most well-consolidated, lithified, and highly competent rocks, such as sandstone, limestone, quartzite, and granite
Joint
A fracture dividing rock into two sections that moved away from each other.
Joint
A characteristic weathering form in massive rocks, granite, dolerite, basalt, and even some sedimentary types such as silicified sandstones, results in the production of spheroidal boulders of unweathered rock, around which are to be observed layers or flakes of disintegrated material.
Spheroidal weathering
What is an interface in the earth system?
Soil
What combines to make soil?
Mineral matter
Water
Air
What is rock and mineral fragments called?
Regolith
What portion of soil supports the growth of plants?
Regolith
What does the texture of souls refer to?
Proportions of different particle sizes
What are the parts of soil textures and how large are they?
Sand (large)
Silt
Clay (small)
What particle in soil has the best texture suited for plant life?
Loam
How does soil get its structure?
Soil particles clump together
What are the four soil structures?
Platt
Prismatic
Blocky
Spheroidal
What are the 5 most important factors that control soil formation?
Parent material Time Climate Plants and animals Slope
When parent material is the bedrock?
residual soil
When parent material has been carried form elsewhere and deposited?
Transported soil
What is important in all geologic processes ?
Time
How does the time relate to different soils evolving?
The time to evolve varies on different soils
What furnishes organic matter to soil?
Plants and animals
What influence does organisms have on soil?
They influence soils physical and chemical properties
What kind of soil do steep slopes have ?
Poorly developed soils
What is a flat to undulating upland surface?
Optimum (angle)
What is orientation?
Direction the slope is facing
What two things does the orientation of soil influence?
Soil temperature
Soil moisture
How do the soil forming processes operate?
Surface downward
What do soil scientists call zones or layers of soil?
Horizons
What is The composition of O horizons?
Organic matter
What is The composition of A horizons?
Organic and mineral matter
What is The composition of E horizons?
Little organic matter
What is The composition of B horizons?
Zone of accumulation
What is The composition of C horizons?
Partially altered parent material
What is the name of O and A horizons together?
Topsoil
What layers are topsoil?
O and A
What is the name of horizons O, A, E, B together
Solum
“True Soil”
What horizons are in solum or “true soil”
O, A, E, B
True or false: there are hundreds of soil types worldwide.
True
What about re the three very generic soil types?
Pedalfer
Pedocal
Laterite
What soil type has an accumulation of iron oxides and Al-rich clays in the B horizon?
Pedalfer
What soil type is in hot, wet, tropical climates?
Laterite
What soil type is best developed under forest vegetation?
Pedalfer
What soil type is associated with drier grasslands?
Pedocal
What soil type has intense chemical weathering?
Laterite
What soil type accumulates calcium carbonate?
Pedocal
Thin, flat plates of soil usually found in compacted soil?
Platy
Vertical columns of soil that might be a number of cm long usually doing in lower horizons?
Prismatic
Irregular blocks
Blocky
Consists of circular peds or granules that are usually separated from each other in a loosely packed arrangement.
Spherical
What is the recycling of earths materials?
Soil erosion
What does natural rates of erosion depend on? (4)
Soil characteristics
Climate
Slope
Type of vegetation
What two things can soil erosion and sedimentation cause?
Reservoirs to fill with sediment
Contamination by pesticides and fertilizers
What is the process of weathering creating ore deposits?
Secondary enrichment
What is secondary enrichment?
Concentrated metals into economical deposits
Secondary enrichment can take place by removing ________ from _______, which leaves the _____ behind
Undesired material
Decomposing rock
Desired elements
Secondary enrichment can take place from the _______ being carried to _____________ and deposited
Desired elements
Lower zones
What are two examples of secondary enrichment?
Bauxite (principle ore of aluminum)
Any copper and silver deposits