Sedimentary Rocks

Sands, gravel, and conglomerates

-Oh my!

Where can I find a sedimentary rock?

Cover approximately 75% of our (continental) surface

Examples:

Sandstone

Conglomerate

Shale

Halite

Formation

Weathering

Erosion/Transportation

Deposition

Compaction

Lithification

Weathering

Weathering- the breakdown of rocks; disintegration of rock

Chemical

CO2 + H2O H2CO3

carbon dioxide + water carbonic acid

H2CO3 + CaCO3 Ca(HCO3)2

carbonic acid + calcium carbonate calcium bicarbonate

Mechanical

Temperature (freeze/thaw, thermal expansion)

Pressure release

Other (crystal growth, organic activity,etc.)

Erosion & Transportation

Erosion- the movement of rocks or weathered products

Agents of Erosion

Wind

Water

Ice

Gravity

Size and shape of clasts relate to transportation

Large and angular

Small and rounded

Deposition

Sediments are deposited or dropped when their transportation no longer has the energy to move the mass.

Compaction

Pore spaces are reduced when sediments are compacted, or pressed together

Lithification

During lithification loose sediments are cemented together to form a sedimentary rock.

The ExceptionsWhen it’s not a Clastic Sedimentary Rock

Organic Sedimentary Rocks:

Chalk

Limestone

Coal

Precipitate Sedimentary Rocks:

Halite (salt)

Gypsum

Name the sedimentary rock!