Lithosphere - Part 2

Frost Action

Mechanical Weathering - Break off small grains to large boulders when water expands and freezes in rock pores.

Granual Disintegration

As water evaporates, crystals grow from the materials dissolved in water which force apart mineral grains.

Mechanical Weathering

When a rock breaks down into progressively smaller fragments without being altered by chemicals.

Oxydation

Metallic elements combine with oxygen to form oxides, like iron oxide (rust).heC

Chemical Weathering

When some or all the minerals in the rock are charged or decaying by agents like water, oxygen, carbon, and other organic acids.

Biological Weathering

Tree roots can exert pressure on rock.

Bacteria, algae, fungi, and lichen can chemically alter minerals.

Factors that influence weathering:

Faster weathering:

• More moisture

• More heat

• Cold (frost action)

• The minerals that make up the rock.

Igneous Rock

Forms from the cooling and crystallization of the earth’s crust.

Extrusive Igneous Rock

Formed from lava on the Earth’s surface. Cools fast = fine grain or no crystals

Intrusive Igneous Rock

Forms from magma beneath the Earths surface (intrusive)

Cools slowly → big crystals

More pressure = darker

Less pressure = lighter

Lava

Molten rock on Earth’s surface

Magma

Molten rock under Earth’s surface

Sediment

Mineral grains broken down from rock

Sedimentary Rock

Pressure from the weight or material deposited compacts and cements sediments into sedimentary rock.

Metamorphic Rock

Rocks go through intense pressure and temperature changes without having to melt. Rock is now stronger and more resistant to weathering.

O horizon

humus, workable, good porosity

A horizon

topsoil, lots of nutrients and organic material

E horizon

Extras from the topsoil leached out

B horizon (subsoil)

Accumulation of leached materials (subsoil)

R horizon

Regolith, partly broken down parent material