Weathering, Erosion, and Deposition

Weathering is...

the breaking up of rock into smaller pieces

Erosion is...

the movement of sediment from place to place by wind, water, ice, or gravity

Deposition is...

the process by which sediments are re-deposited in new locations

what are the two types of weathering?

mechanical and chemical

mechanical weathering is...

when rocks are broken apart by a physical force

chemical weathering is...

weathering that changes the makeup of rocks and minerals

Abrasion

(mechanical) long scratches and grooves gouged into the bedrock as a glacier passes

Ice Wedging

(mechanical) freezing water in the cracks of rocks expands causing rocks to be weakened and fractured

Uploading - exfoliation

(mechanical) the expanding of high pressure rock when exposed to a lower pressure, causing the rocks to expand, and the zone of weakness open up as joints

Organic activity - root wedging

(mechanical) when roots grow or animals dig holes, rocks split apart

Gravitational impact

(mechanical) occurs when gravity pulls soil or ice (glaciers) down a slope, includes landslides

Mass wasting

(mechanical) the transfer of sediments downhill due to gravity

Glaciers carry

boulders along their underside

where is chemical weathering common?

locations that have a lot of water and w/ warm temps

Oxidation

(chemical) when rocks that have metals are combined w/ oxygen and rusts

Hydrolysis

(chemical) reaction where a molecule within the rock is cleaved into two parts by the addition of a molecule of water

Dissolution

(chemical) when slightly acidic water reacts with rock

Dissolution (Carbonation)

(chemical) carbonic acid is formed w/ carbon dioxide and water combine, weak acid can chemically weaken rock

Dissolution (Sulfuric acid)

(chemical) sulfurous gas (given off by volcanoes and factories) can react with water to form sulfuric acid

Plant acids

(chemical) some mosses & lichens produce weak acids that seep into rock and react with the minerals that hold them together causing rock to chemically weather

hydration

(chemical) involves the attachment of H+ and OH-ions to the atoms and molecules of a mineral

factors that influence the rate of weathering

amount of surface area, climate, temp., availability of water

warm temps and abundant moisture lead to...

rapid weathering

zone of accumulation

the area where a glacier forms

zone of wastage

beyond the zone of accumulation where all of the snow from the previous winter melts

valley or alpine glaciers

type of glacier that originates from mountain glaciers and moves down valleys

ice cap

mini ice sheets, covering less than 50,000 k

glacial trough

U-shaped glacial valley

cirque

bowl shaped depression w/ steep sides @ the head of a glacier

horn

A pointed, mountain peak, typically pyramidal in shape, bounded by the walls of three or more

arete

a thin, crest of rock left after two adjacent glaciers have worn a steep ridge into the rock

calving

process by which a block of a glacier breaks off and falls into the sea to form an iceberg

fjord

A long narrow inlet from the sea between steep cliffs or hills

stratified drift

sorted sediments laid down by glaciers

till

unsorted sediments laid down by glaciers

drift

term for all sediments of glacial origin

lateral moraine

moraine that forms along the side of a glacier

medial moraine

when two advancing valley glaciers come together to form a single ice stream in the middle of the glacier

terminal moraine

farthest advance of a glacier

end moraine

ridge of till piled up along the front edge of a glacier.

a solution (dissolution) cave requires

soluble bedrock and abundant groundwater

stalactite

deposit that hangs like an icicle from the roof of a cave

speleothems

term for all cave formations & decorations

formula for caverns in Central TX

H2 CO3