EARTH SCI | Erosion and Transportation, and Deposition and Depositional Land

Erosion

transportation of weather sediments by agents of erosion and to different places

Agents of Erosion

water, glacier, wind

Water as an Agent of Erosion

primary agent of erosion on earth due to the water cycle

Types of Water Erosion

• splash erosion

• sheet erosion

• gully erosion

• valley erosion

• bank erosion

• coastline erosion

• seaside cliff erosion

Splash Erosion

rain drops cause tiny particles of soil to be detached and moved out, this happens when water removes the topsoil from land

Sheet Erosion

raindrops break apart the soil structure and move downslope as water flows over land as sheet

Gully Erosion

after a heavy rain, water flows in narrow channels, eroding gullies into great depth

Valley Erosion

continuous flow of water alongside land and downward movement deepens a valley

Bank Erosion

continuous flow of water wears out stones along the bank of streams and rivers, can be prevented through sacks or riprap stones

Coastline Erosion

waves from the ocean and seas crash onto shorelines and break down rocks into pebbles and reduce the pebbles into sand.

Seaside Cliff Erosion

ocean waves battering seaside cliffs bore holes that may become caves

Glacier as Agent of Erosion

some rocks are embedded in the ice scrape across bedrock, cutting deep, parallel grooves and scratches called glacial striations, glaciers can erode land through plucking and abrasion

Plucking

fractured bedrocks are incorporated into the ice

Abrasion

ice and its load of rock fragments slide over a bedrock

Wind as an Agent of Erosion

• Strong wind wears away soft rocks, also polishes rocks, and cliffs until they are smooth, it erodes materials until nothing is left

• wind blows away silt and sand, leaving the pebbles and cobbles as a continuous cover of stones called desert pavement

• best in deserts and arid regions

Factors of Transportation

• Particle weight

• Size

• Shape

• Surface configuration

• Medium type

• Resistance of particles
  to be detached

Types of Transportation

solution, suspension, traction, saltation

Solution

dissolved and carried by water

Suspension

carried by a medium (air, water or ice)

Traction

rolling, sliding, and shuffling along eroded surface

Saltation

move from the surface to the medium in a quick repeated cycles

Deposition

aggradation or accumulation of weathered sediments to create different landforms

Type of Water-Based Landforms

• Alluvial fan

• Delta

• Flood Plain

• Levee

Alluvial fan

when stream velocity decreases, stream deposits the sediments it carries, forming a this fan-shaped mound

Delta

a stream also slows abruptly where it enters the still water of a lake or ocean, the sediment settles out to form this nearly flat land form

Flood Plain

during a flood, the stream overflows onto this low-lying adjacent land

Levees

a wall built along the bank of a stream to prevent rising water from spilling put of the stream channel onto the flood plain

Types of Glacial Landforms

• glacial till

• esker

• drumlins

• kame

• kettle

• outwash plain

Glacial Till

unsorted rock deposited underneath or near the glacier’s margin and often compacted by the weight of overriding ice

Moraines

layers or ridges of till, examples include lateral, medial, terminal, and supraglacial

Esker

long, snakelike ridge formed as the channel deposit of a stream that flowed within or beneath a melting glacier

Drumlins

elongate hills, usually occurring in clusters formed when a glacier flows over and reshapes a mound of till

Kame

a small mound or ridge of stratified drift, deposited by a stream that flows on top of, within, or beneath a glacier

Kettle

a small depression formed by a block of stagnant ice, many fill with water to become a kettle lake

Outwash Plain

a broad, gently-sloping surface formed when outwash spreads onto a wide valley or plain beyond a glacier

Wind Erosion Landforms

• loess

• sand dunes

Loess

blanket of silt carried by wind in suspension and deposited over broad areas

Sand Dunes

deposits of coarse materials in the shape of hills or ridges