Earth Science - Exogenic Processes (Chapter 7.1-Weathering)

transport

Involves processes by which sediments are moved along from the source to where they are deposited.

Sun's energy

It is energy responsible for exogenic processes, which slowly and steadily tears the landforms down.

Earth's internal heat

It is heat that is much less powerful that of the Sun, and forms the mountains

limestone

It is weathered through dissolution.

Calcite (CaCO3)

it dissloves rapidlyn in acidic water like rainwater

tidal flats

flat, marshy, sandy or muddy areas exposed at low tide and under water at high tide (where most sediment load are deposited)

Solution

movement of soluble minerals (salts).

meander

part of river where deposition occurs

Dissolution

the breaking up or dissolving of something into parts; disintegration. It happens in minerals which are dissolved in water.

Glacial Erosion

the process by which glaciers cut, carve or scratch the earth's surface

frost wedging

the repeated thawing and freezing of water in the cracks of rocks

River bends

where erosion occurs in the river

Saltation

Small pebbles and stones are bounced along the river bed. (Bouncing of sand grains as they are picked-up, carried along and dropped repeatedly.)

Thermal expansion

An increase in the size of a substance when the temperature is increased. When a rock is exposed to high temperature, its outer layer expands due to baking.

biological weathering

Any weathering caused by the activities of living organisms

Hydrolysis

Breaking down complex molecules (polymers) by the chemical addition of water(like digestion). Water reacts with the minerals and breaks them down. It occurs faster in slightly acidic water.

Halite (NaCl)

Compound that dissolves rapidly in pure water

Warm and wet climate

Type of climate good for both chemical and mechanical/physical weathering. Chemical reactions occur at a faster rate.

V-shaped valley

Valleys eroded due to fast flowing water often found in upland areas

biological weathering

Weathering that occurs in roots of plants, when fungi and lichens secrete organic acids that dissolve minerals and the nutrients are taken by these organisms.

Wind erosion

When the wind picks up dirt and dust and moves it from one place to another. It commonly occurs in flat, bare areas or dry, sandy, and loose soils.

Oxidation

A chemical change in which a substance combines with oxygen, oxygen reacts with minerals forming oxides.

Hydration

A chemical weathering process involving water that is added to a mineral, which initiates swelling and stress within the rock, mechanically forcing grains apart as the constituents expand.

Hydration

A chemical weathering process when water is absorbed into the crystal structure of the mineral, causing it to expand.

exfoliation

A mechanical weathering process which removes protuding overlying layers and esposing the weathered down dome of the underlying layers.

exogenic processes

Forces generally originating in the atmosphere that, aided by gravity, shape Earth's surface; erosion by running water, glaciers, wind, and waves are examples It is also driven by solar energy.

Tidal currents

Horizontal flow accompanying the rise and fall of tides

root wedging

In this type of physical weathering, the roots of a plant (typically a tree) wedge into a crack in a rock and, as the plant growns, splits the rock.

Water

Most common erosion agent.

Suspension

Movement of fine particles like silt and clay.

salt wedging

Rock disintegration caused by the crystallization of salts from evaporating water. It usually happens in deserts and along coastal areas.

longshore drift

The movement of water and sediment down a beach caused by waves coming in to shore at an angle. It is the mechanism that transports river sediments along the shoreline.

Weathering

The on-site breaking down of rocks and other materials on the Earth's surface and its eventual transformation into sediments.

Mechanical weathering

The physical disintegration of rock, resulting in smaller fragments without changing its internal composition.

Chemical Weathering

The process in which rock is broken down by changes in its chemical makeup

traction

The rolling or dragging of boulders(large grains) and pebbles along the river bed, aided by the push of smaller grains.

Erosion

The separation and removal of weathered and unweathered rocks and soil from its substrate due to gravity or transporting agents like wind, ice or water.

U-shaped valley

The shape of a valley formed by the erosion of a glacier

exfoliation

Through this, intrusive rocks such as granite usually split into onion like sheets parallel to the surface.