weathering and mass movement

hydrolysis

A form of chemical weathering where there is a chemical reaction of a substance with water.

oxidation

A form of chemical weathering where there is a chemical reaction of an iron bearing substance with oxygen.

glacier

A large mass of moving ice and snow on land

river

A large, flowing body of water that usually empties into a sea or ocean.

soil horizon

A layer of soil that differs in color and texture from layers above and below it

soil

A loose mixture of rock fragments, organic material, water, and air that can support the growth of vegetation

parent rock

A rock that becomes something else -- in this case, soil.

windbreak

A row of trees planted to block the wind and prevent soil erosion.

slump

A type of mass movement that occurs when a mass of material moves down a curved slope

surface area

Although pieces of rock continue to get smaller each time a rock breaks apart, *more surface is exposed and surface area increases*. Surface area refers to the amount of the material exposed.

beach

An area of wave-washed sediment along a coast.

mass movement

Any one of several processes by which gravity moves sediment downhill.

living things that live in soil

Bacteria, fungus, earthworms, moles, and ants

abrasion

Bumping and breaking up of rocks as the collide. Rocks become *smaller, rounder and smoother.*

soil properties

Can be observed (such as soil profile, composition, texture or particle size), or measured, (such as permeability and pH).

carbonation

Carbonic acid in rain causes minerals to dissolve. Ex. marble gravestones.

particle size

Classified by size ranging from coarse sand to very fine sand to silt, and finally to clay

soil formation factors

Climate, parent material, organisms, slope, time

organic

Comes from a living thing

inorganic

Comes from a non-living thing

desertification

Degradation of land, especially in semiarid areas, primarily because of human actions like excessive crop planting, animal grazing, and tree cutting.

texture

Depends on the size of individual soil particles and is determined by the proportions of particle sizes that make up the soil

soil composition

Describes how soil is a mixture of rock particles, minerals, decayed organic material, air, and water

differential Weathering

Different parts of a rock weather at different rates

permeability

How freely water flows through open spaces between soil particles

sand dune

Large deposits of sand dropped when the wind stopped blowing. The location of one can shift frequently.

sand

Largest soil particle.

silt

Medium soil particle

soil erosion

Movement of soil components, especially topsoil, from one place to another, usually by wind, flowing water, or both. This natural process can be greatly accelerated by human activities that remove vegetation from soil.

agents of erosion

Natural forces include: moving water, glaciers, waves, wind and gravity.

frost wedging

Occurs in climates with freezing and thawing temperatures; water gets into cracks and creases of rock. Water expands when it freezes and causes cracks in rocks to get bigger and break apart. Ex: pot holes.

chemical weathering

Occurs on the surface of rocks and changes the composition of the material. This causes rocks to weaken and makes it easier for them to break apart (physical weathering). Dominates in warm moist climates.

rockfall

Occurs when rocks or rock fragments fall freely through the air

pores

Open spaces between the soil particles that allow water to flow through

frost action

Physical weathering when melt water seeps into rock, freezes, expands, and breaks a rock.

water erosion

Process that moves WAVES to shape the land creating new land forms

wind erosion

Process that uses WIND to move sand to create new land forms

mudflow

Quickly moving downhill flow of soil and rock fragments containing a large amount of water

acid rain

Rain polluted with emissions from fossil fuels (oil, coal, & natural gas).

deflation

Removal of loose material from Earth's surface by wind.

Onion Skin

Rock expands in heat during day and contracts when cool at night. Constant process causes outer rock to 'peel' off

physical (echanical) weathering

Rocks are broken up into fragments; does not change the composition of the rock but it does create more *surface area*. The dominant climate condition for this type of weathering is cold and moist.

rockslide

Rocks do not fall freely, but slide down a slope

root action

Roots grow into and under rocks and pry them apart causing cracks to get bigger. Ex: cracks in the sidewalk.

earthflow

Slow-moving downslope movement of water-saturated, clay-rich sediment, most characteristic of humid regions

clay

Smallest soil particle.

gravel

Soil particles that are larger than 2 mm

loam

Soil that is an even mix of sand, silt, and clay. Loam is the best for growing crops.

soil profile

Soils form in layers, or horizons, and all the layers make up this

exfoliation

Surface of the rock "peels" off. Unloading - caused by uplift and exposure of rock that was once deep underground and decreases pressure on rocks.

weathering

The breaking down of rock into smaller and smaller pieces by wind, water and ice.

gravity

The force that pulls rock and other materials downhill

abrasion

The grinding away of rock by other rock particles carried in water, ice, or wind

soil horizon

The layer of soil that differs in color and texture from the layers above or below it.

deforestation

The loss of forest cover in a region that results from the trees in a forest being destroyed faster than they can grow back.

rate of weathering

The most important factors that determine the rate at which weathering occurs are the type of rock and the climate. Rocks that are permeable have tiny connected holes in them, so materials can weather them down at a fast rate ( water seeps through)

porosity

The percentage of the total volume of a rock or sediment that consists of open spaces.

erosion

The process by natural forces of moving rock and soil from one place to another

deposition

The process where agents of erosion deposit, or lay down, sediment. It changes the shape of the land.

avalanche

The rapid movement of snow and ice down the side of a mountain.

humus

The remains of dead plants and animals found in the soil.

creep

The very slow downhill movement of rock and soil.

loess

Thick deposits of windblown dust.

A Horizon

Topsoil. Contains lots of humus and micro-organisms.

hydration

Water weakens the rock and the rock crumbles. Ex: feldspar becomes clay.

triggers of mass movement

Water, oversteeped slopes, earthquakes, removal of vegetation

sediment

Weathered pieces of rock, soil, and/or remains of dead plants and animals

landslide

a slide of a large mass of dirt and rock down a mountain or cliff

C Horizon

a soil horizon; made up of larger pieces of rock that have not undergone much weathering

biological weathering

any weathering that's caused by the activities of living organisms.

mechanical weathering

breaking down of rocks by physical forces, like pressure, ice wedging, freezing and thawing

mass erosion

downhill movement of weathered materials due to the gravity (landslides,mudflows,earthflow and creep.

C horizon

horizon made of rock fragments on top of unweatered bedrock

regolith

layer of weathered rock fragents covering much of the earths surface

slide

mass movement that occurs when a block of material moves suddenly along a flat, inclined surface

flows

mass movements of material containing a large amount of water, which move downslope as a thick fluid

major soil components

mineral matter, humus, water, and air

most important factors of soil formation

parent material, time, climate, organisms, and slope

angular rock

rocks that are not smooth - usually formed from gravity/ mechanical weathering

soil texture

size of soil particles; sand, silt, clay (largest to smallest).

oversteepened slope

slope with steepness that exceeds the stable angle

residual soil

soil that forms on bedrock

transported soil

soil that forms on unconsolidated deposits from which its parent material was moved from another location by gravity, water, wind, or ice

bedrock

solid unweathered rock lying beneath surface deposits of soil

B horizon

subsoil; contains fine clay particles washed out of the A horizon

biological activity

the activities of organisms, including plants, burrowing animals, and humans that can cause mechanical and chemical weathering

water

the most important agent of chemical weathering

differential weathering

the process in which different parts of a rock mass weather at different rates

parent material

the starting material of soil consisting of rock or sediment that is subject to weathering

A horizon

topsoil horizon that is generally gray to black, contains the remains of living things (humus)