Sedimentary RockStudents will be able toDescribe how rocks are formedClassify the sedimentary typesList uses for this rock type

Changing Earth’s Surface

1. WeatheringPhysical breaking of rock

2. Mass WastingFalling due to gravity

3. ErosionRemoval by mobile agents (water, wind, ice…)

Weathering

Frost Wedging

Water expands 9% when frozen

Repeated cycles will break apart rocks

Weathering

Unloading

When pressure is released by exposure

Rock cracks in sheets when it expands

Weathering

Biological

Damage caused by roots and animals

Weathering

Chemical

Acid rain, pollution, …

Mass Wasting

Spheroidal

Erosion

Loss of material

usually loose soil

Sedimentary Rock

5% of Earth’s outer crust

High Value

Contains major energy resources

Contains fossil record

Formation

Compaction

Weight of material on top presses into rock

Cementation

Minerals enter spaces between to harden

Types

Clastic

Rock fragments squeezed together

Organic

Formed from remains of living things

Chemical

Formed from chemical during evaporation

Clastic

Shale

50% of all sedimentary rock

Made from tiny pieces of clay

Black due to abundant carbon (living)

Formed in oxygen poor area (swamp)

“prevents decay”

Sandstone

20% of all sedimentary rock

Small grains (wind or river)

Conglomerate

Large particles

Steep slopes or fast streams

Organic

Limestone

10% of all sedimentary rock

Mostly calcite

Skeletons of coral reefs

Accumulation of shells

Caves from minerals above

Coal

Many plant parts

Low oxygen formation (swamp)

High heat and pressure to solidify

Major source of US electrical energy

Chemical

Evaporites

Seawater and salt flats evaporate

Quiz

Homework

• Describe how sedimentary rocks are made