APES soil formation

reading check 229-250

soil

minerals from rocks + organic matter from decomposing organisms

soil erosion

soil is worn away and carried away from water/wind

3 types of rock

1. igneous

2. sedimentary

3. metamorphic

igenous rock

• formed by magma/heat

2 types of rock

• basaltic rock: dark colored, high in iron magnesium, calcium, dominant rock in the oceanic rock

• granitic rock: light colored, contains feldspar, mica, and quartz. dominant rock in continental crust, it can form sand.

Sedimentary rock

• formed by loose pieces of rock get buried and squeezed together until they become solid rock. (sediments)

• fossil record

metamorphic rock

• formed by existing rock that was changed because of heat and pressure

rock cycle

• rocks changing from one type to another over a very long time.

cycle:

MAGMA
⬇ cools + hardens
🪨 IGNEOUS ROCK
⬇ weathering + erosion
🏖 SEDIMENT
⬇ pressure/compression
🪨 SEDIMENTARY ROCK
⬇ heat + pressure
🔥 METAMORPHIC ROCK
⬇ melting
🔥 MAGMA
⬆ And the cycle starts again!

• does not follow the same cycle everytime.

weathering

the natural breakdown or dissolving of rocks and minerals on Earth's surface by water, air, ice, and living things

physical weathering

physically broken apart, but its chemical makeup stays the same.

chemical weathering

chemically changed or dissolved.

acid percipitation/rain

rain, snow, or other precipitation that contains unusually high amounts of acids.

erosion

The physical removal of rock fragments from a landscape or ecosystem.

5 properties that determine soil properties

1. parent material - the underlying rock the soil comes from

2. climate - temperature, humidity

3. topography - the slope and shape of the land

4. organisms - plants, animals, bacteria, fungi

5. time - how long soil has been developing

soil horizons

• O - organic matter. dead leaves, twigs, animals, humus ( very decomposed organic matter)

• A - topsoil, organic matter + minerals, lots of nutrients, important for plant growth

• E - leaching layer, leaching removes minerals from this layer, not always present, found in some acidic soils

• B - sub soil, metals

• C - least weathered layer, very similar to parent material

soil minerals

3 clay, = smallest

2 slit = medium

1 sand = largest

the bigger the particle, higher the porosity

porosity = amt of air between soil particles.

sand

• large, loose particles

• high permeability ( water can move through )

• lower water holding capacity, drains easily

• roots can move around

clay

• tiny, tight particles

• low permeability

• low water holding capacity

• roots can move through easily as well

slit

in between clay n sand