Unit 3 Exam - Land and Soil formation

Core

Solid central part of the Earth’s layers

Mantle

Thick layer of elastic rock, part of the Earth’s layers

Crust

Least dense and outermost of Earth’s layers

Continental Crust

Thicker part of the crust, less dense, granite

Oceanic Crust

Thinner part of the crust, more dense, basaltic rock

Lithosphere

Solid crust and upper mantle, includes tectonic plates

Asthenosphere

Layer of rock that can flow in convection currents

Plate tectonics

2-15 cm of movement per year of large plates of lithosphere

Convergent

Type of plate boundary where plates move towards each other

Divergent

Type of plate boundary where plates move away from each other

Oceanic-oceanic

Type of convergent plate movement, denser plate subducts, forms trenches and volcanic islands

Oceanic-continental

Type of convergent plate movement, denser plate subducts, forms trenches and volcanoes on land

Subduction

Term for when a denser plate goes underneath another plate, moves towards Earth’s center and melts

Continental-continental

Type of convergent plate movement, less dense crust buckles and moves up, forms mountains

Oceanic

Type of divergent plate movement, heat from convection drives plates apart, mid-ocean ridge

Continental

Divergent plate movement, heat from convection drives apart, forms rift valley on land

Transform

Plates rub against one another, causes faults and earthquakes

Earthquakes

Due to movement at plate boundaries and faults, stick together due to friction between plates, when plates overcome force and move stored energy is released

Tsunamis

Caused by earthquakes, volcanic eruptions, and large coastal landslides displace large volumes of water

Reserves

The known quantity of a resources that can be economically recovered

Ore

Rock that contains a concentration of a mineral that can be profitably mined and the mineral extracted

High grade ore

Ore with a higher concentration of mineral, requires less effort and resources, less waste and pollution

Low grade ore

Mined after better resources are depleted, lower concentration of mineral, more resources to process, more waste and pollution

Strip Mining

The removal of strips of soil and rock to expose ore

Open-pit mining

A mining technique that uses a large visible pit or hole in the ground

Mountaintop Removal

A mining technique in which the entire top of a mountain is removed with explosives

Subsurface Mining

Used to get to deeper target resources. More expensive, dangerous. May collapse, fires and explosions, black lung

Mining Spoils

Unwanted waste materials created during the process of removing ore from rock

Waste Rock

Rock and soil that is embedded within the ore, removed in order to get to ore

Overburden

Rock and soil that sits above the ore

Tailings

Byproducts of removing compounds from ore, waste rock, water, trace amounts of metals, additives (chemicals)

Heavy Metals

Found in mine tailings, arsenic and mercury, extremely harmful to environment, acid drainage, suspended particles in water

Soil particles airborne

Due to the removal of soil and vegetation, disrupts habitats, removes surface features →increased erosion

Reclamation

Returning land to its original state, covering tailings with rock and soil, hydro-seeding, vegetation, only barely works

Soil

A system consisting of disintegrated rock, organic matter, water, gasses, nutrients, microorganisms. Medium for plant growth, breaks down organic matter, recycles nutrients, habitat, filters water

50

What percent of soil is mineral matter

5

What percent of soil is organic matter

45

What percent of soil is pore space (½ air ½ water)

Physical Weathering

Mechanical breakdown of rocks and minerals, expansion of water as it freezes, water flowing over rocks, wind blowing rock particles

Chemical Weathering

Breakdown of rock and minerals by chemical reactions or dissolving, acid precipitation

Acid precipitation

Precipitation high in sulfuric acid and nitric acid

Biological Weathering

Breakdown of rock by living organisms, growing plant roots, microbial activity, burrowing animals

Parent material, climate, topography, organisms, time

Weathering and the accumulation of organic matter are influenced by

Parent Material

Factor of soil composition, its composition influences soil formation

Climate

Factor of soil composition, weather, moist areas accelerate weathering

Topography

Factor of soil composition, hills and valleys affect exposure to sun, wind, water, and influence soil movement

Organisms

Factor of soil composition, plants and decomposers adding organic matter

Time

Factor of soil composition, soil formation can take centuries, decades, and millennia. Soil is renewable at a very slow rate

Soil Horizon

The movement and sorting of soil particles creates distinct layers

Soil Profile

The entire cross-section of soil

Leaching

Minerals dissolved or suspended in water can be transported downward in this process

OAEBC

Layers of the soil, top to bottom

O Layer

Layer of soil with organic matter, in various stages of decomposition

A Layer

Layer of soil, Topsoil, Zone of overlying organic material mixed w/ underlying mineral material

E Layer

Layer of soil with zone of leaching of metals and nutrients; occurs in some soils beneath either O or A layer

B Layer

Layer of subsoil, zone of accumulation of metals and nutrients

C Layer

Layer of subsoil, least weathered portion of the soil profile, similar to parent material

Clay

Smallest soil particles, less than 0.002 mm in diameter

Sand

Largest soil particles, between 0.05 and 2mm in diameter

Silt

Particles in between clay and sand

Loam

Soil with an even mixture of each particle type

Soil Triangle

Used to determine soil texture based on relative abundance of sand, silt, and clay

Soil Porosity

Ability to store water, measure of open spaces or pores

Porosity

Number of spaces between particles, smaller the grain size the higher the levels

Soil Permeability

Ability of water and gases to flow through the soil. Sand drains quickly due to large loosely packed particles, clay drains slowly

Water Holding Capacity

The amount of water that a given soil can hold for crop use, controlled by texture and organic matter content, small particles→large SA, more water, organic matter = affinity for water, leaks less nutrients

Soil Fertility

Soils of intermediate pH best, too acidic or alkaline→bad, must be able to provide nutrients, medium to hold water, lots of organic matter, structure for rooting

Erosion

Removal of material from one place and its transport to another by wind or water

Deposition

Eroded material is left at a new location

Desertification

A land degradation when more than 10% of productivity is lost, caused by wind and water erosion, destroys land and burys houses