2ND QUARTER ESCI: EXOGENIC ROCESSES

WEATHERING

is the physical disintegration or chemical alteration of rocks at or near the Earth’s surface.

MECHANICAL, CHEMICAL, BIOLOGICAL WEATHERING

What are the three types of weathering?

MECHANICAL WEATHERING

rocks are broken down into smaller pieces without changing their

composition (doesn’t change what they’re made of)

CHEMICAL WEATHERING

rocks break down as their minerals change in composition (they become different substances)

BIOLOGICAL WEATHERING

– is the disintegration or decay of rocks and minerals caused by chemical or physical agents of organisms.

EXFOLIATION, ICE WEDGING/FROST ACTION, TEMPERATURE CHANGES, SALT WEDGING, ABRASION

What are the 5 types of mechanical weathering?

EXFOLIATION

soil and rock is removed (glaciers or uplifting), exposing rock found deep underground

EXFOLIATION

This releases the pressure causing thesurface of the rock to expand and eventually crack

ICE WEDGING/FROST ACTION

water enters small cracks in the rock. When it freezes, it expands and forces the crack to open more. The process repeats over again until the rock breaks apart.

TEMPERATURE CHANGES

Daily (diurnal) and seasonal temperature changes affect certain minerals and facilitates the mechanical weathering of bedrock. Warmer temperature may cause some minerals to expand, cooler temperatures cause them to contract.

SALT WEDGING

Similar to frost wedging. Growth of salt crystals breaks rocks apart; Most effective in coastal environments and semi-arid environments.

ABRASION

it is the action of rocks sediments grinding against each other and the wearing away of exposed surafces.

PLANT ROOTS

The deep roots of tress often break apart rocks

LICHEN & MOSS

These low to the ground plants can grow on rocks and eventually break them apart

CHELATION

Organisms such as lichen and moss produce acids that breakdown rocks

PLANTS, HUMANS, ANIMALS

What are the three types of biological weathering?

HYDROLYSIS

water (hydro) reacts with minerals such as feldspar and form clay

HYDRATION

This is when minerals in the rock absorb water and expand< creating stress which causes the disintegration of rocks.

OXIDATION

oxygen reacts with some minerals, especially those containing iron (magnetite) to form rust (called iron oxide) This occurs faster

with water!

New deposits: white-yellow

Weathered deposits: reddish-brown

Oxidative weathering of mineral deposits: New deposits are _____, weathered deposits are ______

CARBONIC ACID

Carbon dioxide (CO2) dissolves in water to form this acid; ca cause minerals to dissolve, especially those containing calcite

GNARLED ROCK

A formation of limestone chemically weathere by acid rain

EROSION

moving of rock material from one place to a new location

DETACHMENT OF PARTICLAS

LIFTING THEM

TRANSPORTING THEM

What are the three processes that must take place in erosion?

Flowing water

Wind

Waves

The three gents of erosion are?

MASS WASTING

It is a rapid form of erosion that works under the influence of gravity in combination with other erosional agents.

ROCK FALLS

It occurs when rock becomes dislodge because its change in potential energy becomes too great to maintain, and the potential energy becomes kinetic energy which cause the rock fragment to fall, restoring equilimbrium.

DEBRIS AND MUDFLOWS

Are mass wasting events that form when heavy rainfalls producw large amounts of runoff that transport eroded soils, sedminets and plant debris down slope where the flows eventually spread out across valley bottoms.

SLUMP

Fairly common form of mass wasting where the rock or soil collapses, breaks off from the hill slope, rotates slightly and slumps downhill.

CREEP

It is the slowest mass wasting process that invloves a very gradual downhill movement of soil, bedrock, and weathered rock fragments.

DEPOSITION

laying down of sediment that has been transported by a medium such as wind, and water.