🕯 external earth processes 🍀

weathering

The breaking down of rocks and other materials on the Earth's surface.

weathering, erosion, sedimentation, and mass wasting

are essential parts of the rock cycle because they transfer solid rocks into sediments

mountains

weathered and eroded

lakes

have been filled with sediments

plains

have been formed

weathering

a slow but continuous process affecting all substances exposed to the atmosphere

mechanical weathering

occurs when rocks break into pieces without changing their chemical composition

chemical weathering

occurs when the chemical composition of the rock is changed due to the action of other substances

mechanical weathering

causes rocks to be broken into smaller pieces

mechanical weathering

this type of weathering does not change the chemical composition of the rock is changed due to the action of other substances

temperature, frost action, abrasion, and the action of living things

agents of mechanical weathering

temperature

rocks break because of the changes in temperature. during the day, the earth's surface is heated by the sun. as the surface of the rock is heated, it expands but it remains cool inside

drops

during the night, when the temperature ___, the surface of the rock is cooled and the rock contracts

exfoliation

the repeated changes in temperature causes the surface of the rock to peel off, this type of breaking off is called ___

frost action

a unique property of water that it expands when it freezes.

frost action

occurs when water seeps into the small cracks of rock layers

frost action

when air temperature drops below the freezing point of water, the water within the cracks expands

frost action

as the water expands, it exerts pressure to the surrounding rocks that causes it to break

abrasion

this is the wearing off of rocks by solid particles causes abrasion of the rocks leading to unusual rock formations of the Earth's surface

running water

causes abrasion as it carries other rock particles

rock particles

scrape the rocks in the riverbed causing the rocks to become rounded and smooth

action of living things

plants, animals, and even humans can cause mechanical weathering

plant roots

try to push through the underground rocks to get their needed nutrients

roots

as they mature, the ___ grow bigger and longer and exert pressure on the rocks causing them to break

burrowing animals

there are ____ that build tunnel into the rocks to create a space where they live

rocks to break

the construction of roads, dams, power plants, and other types of groundwork by humans cause?

chemical weathering

changes the mineral content and the chemical composition of rocks

minerals

as chemical changes occur, __ may either be added or removed from the rocks

water, oxygen, carbon dioxide, sulfuric acid, and acids from plants and animals

chemical changes

water

almost all chemicals

weathering

is due to the action of weathering

water

can dissolve most of the minerals present in rocks

water

can form acids when it combines with some of the gases in the air

water

it can also combine with minerals to form a different kind of mineral

water

feldspar + water = ?

oxygen

combines with other substances to form entirely new substances

iron-bearing rocks

when ___ are exposed to the surface, their physical properties and chemical composition may change

rust

iron + oxygen in the air = ?

rust

the rocks become brittle and break easily

carbon dioxide + rain water

a weak solution of carbonic acid

sulfur oxides

are produced when fossil fuels are burned

sulfuric acid

sulfur oxides + rain water = ?

sulfuric acid

stronger than carbonic acid. easily corrodes rocks, metals, and other materials

acids and chemicals from organisms

organism such as plants can also cause chemical weathering, they produce acids and other chemicals that dissolve some minerals in the rocks

soil formation

the weathering of rocks on the earth's surface results in rock formation

weathered rocks

smaller pieces

smaller pieces

are further broken down into soil

soil

is very important to living organisms

plants

depend on soil for food, nutrients, and minerals

plants

holds water that the plants need

animals

depend on soil indirectly by eating the plants, or eating other animals that eat plants

residual oil

soil remains on top of its parent rock or the rock from which it was formed

residual oil

has the same composition as the parent rock

wind, water, glaciers, waves

what moved the soil

transported soil

soil that is moved by wind, water, glaciers, waves

bedrock

the parent rock beneath the residual and transported soils

soil

the product of weathering, is carried away by erosion to other places

erosion

the process by which soil and weathered rocks are transported from one place to another

eroded rocks and soils

are deposited in other places

deposition or sedimentation

process through which sediments are transported to another location

wind

the most active agent of erosion in desserts, open fields, and beaches

wind

in these places, loose materials are abundant and can be easily picked up and carried by the wind

speed

the amount of rock and soil that can be blown away by the wind depends on its ___

the faster the wind blows

the more particles it can carry

as the speed of the wind decreases

the particles that it can no longer carry are deposited as dunes and loess

dunes

are mounds that are built by wind consisting of loose sands

loess

is the deposit of fine sand and silt

loess

light in color and without visible layer

loess

it may be several meters thick and can form a nearly vertical cliff

loess deposits

are very fertile

waves

constantly erode and shape the shoreline

shoreline

is where the body of water and land meet

waves

carry large amounts of sand, rock, particles and shells

waves

these solid particles are then deposited in other parts of the shoreline

shape of the shoreline

is always changing and deposits form beaches, sand bars, and spits

beaches

consist of fine sand or large pebbles that are carried by waves to the shores of seas and lakes

sandbars

Are submerged or partly exposed ridge of sand or coarse sediment that is built by waves offshore from a beach

spits

are elongated ridge of sand that stretches from the land to the mouth of a nearby boy

running water

one of the major agents of erosion

running water

has a greater impact on the earth's surface

runoff

the rainwater that flows on the surface and flows to the rivers and streams

stream or river

can carry large amount of sediments

sediments are deposited

when the flow of rivers and streams slow down ->

large sediments

usually settle on the riverbed while smaller ones are deposited along river banks forming oxbow lakes, alluvial fans, deltas, flood plains, and levees

oxbow lake

is a U-shaped body of water that forms when a wide meander from the main stem of a river is cut off, creating a free-standing body of water.

alluvial fan

is a fan-shaped deposit of gravel, sand, and even smaller pieces of sediments, such as silt, formed when the stream flow suddenly slows down

delta

a landform created by the deposition of sediments carried by a river as the stream flows to a lake or an ocean

flood plain

is a flat area of land close to a river or stream

flood plain

stretches from the banks of the river extending toward the outer edges of a valley

levee

a natural wall that blocks the water created by the deposit of large particles

levee

may be used to increased available land for habitation or divert a body of water, so the fertile soil of a river or seabed may be used for agriculture

levee

prevents rivers from flooding cities during storm surges

levee

if it breaks, water may be released and flooding may occur

glaciers

erode surfaces through abrasion

glaciers

moves along a valley, it carries with it rock debris, such as large boulders and smaller particles

moraine

is the accumulation of dirt and rocks that have fallen onto the glacier surface or have been pushed along by the glacier as it moves

dirt and rocks

can range in size from powdery silt to large rocks and boulders

drumlin

is an elongated hill with the shape of an inverted spoon or half-buried egg, which is formed by glacial ice acting on underlying unconsolidated sediments or ground moraine

meltwater deposits

are sediments carried and deposited along the meltwater streams, which are formed when glaciers start to melt

iceberg deposits

Are rocks and sediments that are picked up from land and deposited on the ocean floor by melting icebergs