61 terms

Unit Four Test Review - Weathering


Terms in this set (...)

What part of the water cycle is not affected by gravity?
Name the four processes of the water cycle.
Precipitation, Transpiration, Evaporation, and Condensation
What is the source of energy for the Water Cycle?
The sun
What are the two types of weathering?
Mechanical and Chemical
What is Mechanical Weathering?
A process where rocks break down into smaller pieces by a physical means.
What is Chemical Weathering?
The process by which rock is broken down because of chemical interactions with the environment.
How do waves and water mechanically weather rocks?
Waves break and weather shorelines
How does wind mechanically weather rocks?
Wind blows sand and silt against exposed rocks
How does ice wedging mechanically weather rocks?
Rocks break because water expands when it freezes.
How does gravity mechanically weather rocks?
Landslides and avalanches expose new surfaces for further weathering and falling rocks break up other rocks.
How does root wedging mechanically weather rocks?
Plants send out roots for nutrients. These roots can move into smaller spaces and cracks. They eventually grow and can slit the rock apart.
How does animal burrowing mechanical weather rocks?
Animals dig holes and expose new rocks to the effects of weathering. The holes allow water and other weathering agents to reach the rock layer.
What is abrasion?
The collision of rocks results in breaking and weathering away of rock.
What is exfoliation?
Rock breaks into curved sheets that peel away from underlying rock.
Over time, what happens to a rock as it weathers?
Its edges go from angular to rounded.
In ice wedging, why do the cracks in the rock get wider?
Ice expands when it freezes.
What is hydrolysis?
Chemical weathering by water. A chemical reaction between water and minerals in a rock forms new rocks.
What is oxidation?
Elements combine with oxygen in chemical process.
An example is rust.
What is carbonation?
Carbonation is when a compound is changed into a carbonate compound.
Carbon dioxide dissolves in water to form carbonic acid. Carbonic acid breaks down compounds chemically.
What is acid precipitation?
Compounds that combine with water in the atmosphere to produce weak acids and fall to Earth.
What is Differential Weathering?
Softer, less resistant rocks wear away at a faster rate than more weather resistant rocks.
What kind of climate has the most weathering?
Wet, hot climate
What kind of climate has the least amount of weathering?
Dry, cold climate
How does surface area increase weathering?
More Surface area = more exposure and greater rate of weathering.
How does mechanical weathering make chemical weather go faster?
Mechanical weathering makes chemical weathering faster by breaking rock into smaller pieces and exposing more surface area.
What is soil?
A mixture of minerals, water, gases, and remains of dead organisms
What is regolith?
Layer of weathered rock fragments.
What is bedrock?
Solid un-weathered rock that lies beneath soil and regolith.
Describe some characteristics of sand
- Largest of the three types of particles.
- Size between 2 and 0.06 mm.
- Feels gritty.
- Porous - water runs quickly through sand.
- Doesn't hold nutrients.
- Particles do not stick together.
Describe some characteristics of silt
- Medium sized particles.
- Size between 0.06 and 0.002 mm.
- Feels soapy or silky.
- Doesn't hold easily together.
- Holds water better than sand.
- Can become difficult to drain.
- Holds nutrients and makes fertile soil.
Describe some characteristics of clay
- Smallest of the soil particles.
- Size less than .002 mm.
- Feels smooth and sticky when wet when wet.
- Very little space between particles - non porous.
- Particles stick together easily.
- Holds water well that it can easily become waterlogged.
Name the top three horizons in soil and describe them.
O Horizon - includes humus - dark, organic material from decayed remains plants/animals - is not always present in soil.
A Horizon - topsoil - mixture of organic materials, living organisms and small rock particles - source of leached materials.
B Horizon - subsoil - minerals leached from topsoil, clay, some humus - larger rock particles with organic matter and inorganic compounds.
What do the characteristics of soil depend on?
They depend on the parent rock - rock from which the soil was weathered . A good example is Georgia Red Clay which came from iron rich rocks.
What is the soil type best for gardens and growing plants?
Soils that are best for gardens and growing plants are loams. Loams are a fertile soil of clay and sand containing humus.
Be able to read the soil triangle. What soil types is 20% clay, 60% silt, and 20% sand?
Silt loam is the soil type.
What is groundwater?
Water under the surface of the ground.
How is groundwater transported below Earth's surface?
Through cracks and spaces/pores between rock particles.
What is Infiltration?
When the water enters the soil surface after falling from the atmosphere.
What is percolation?
The downward movement of water from the land surface into soil or porous rock.
What is Porosity?
The percent of rock or sediment that consists of open space is porosity.
What are two factors that porosity depends on?
Porosity depends on the number and size of pores in soil.
How does the porosity of sand, silt and clay differ?
Sand is the most porous with the biggest pores. Clay is the least porous with the smallest pore space. Silt is somewhere in between.
What is permeability?
The ease with which water passes through a porous material is permeability.
What are the two factors that affect permeability?
Factors affecting permeability include how large the pores in the substance are and how well the particles fit together.
What is the relationship between POROSITY and PARTICLE SIZE?
As particle size INCREASES, porosity INCREASES.
What is the rock that seems to weather most often?
What is the difference between a cave and a cavern?
A cave is a natural opening, usually in rocks, that is large enough for human entry and a cavern is multiple caves.
Stalactites, Stalagmites, and columns are all cave formations that contain what material?
Dissolved calcite drippings
What causes a sinkhole?
A cave or cavern collapses, filling with sediment from the surface.
Why does Karst Topography form?
It is caused by chemical weathering of limestone by groundwater.
What types of weather, chemical or mechanical, is coastal weathering?
Mechanical Weathering
What cuts into coastal headlands to form arches, stacks, and caves.
Waves (wave action)
What type of weathering forms Karst landforms?
Chemical Weathering - carbonation
Is groundwater on top of the ground or under the ground?
Groundwater is water beneath Earth's surface - it infiltrates the surface and then percolates through spaces/pores in rock and sediment.
What is an aquifer?
An aquifer is a body of rock that stores underground water and allows it to flow.
What pulls water into the ground?
Gravity pulls water down - fills pores in rock - until it hits impermeable rock.
What is the difference between the saturated zone and the unsaturated zone?
The unsaturated zone is the zone between water table and surface and the Saturated zone is the level where pore space is completely filled with water below the unsaturated zone.
What is the difference between a confined aquifer and an unconfined aquifer?
In unconfined aquifers, water infiltrates easily from surface.
In confined aquifers, water is trapped by impermeable rock or clay between layers of rock.
What do we use the water in aquifers for?
Aquifers provide water for drinking, cooking, cleaning, agriculture, and industrial Uses
How is an aquifer recharged?
An aquifer is recharged by infiltration of precipitation.
What type of material is NOT permeable to water?
Rock and pure clay