Sedimentary Sedimentary RocksRocks

Sedimentary Rocks Sedimentary Rocks are #1are #1

Earth’s crust was made of IGNEOUS rocks

But 75% of the rocks on the Earth’s crust are SEDIMENTARY!

Why?

Sedimentary rocks are Sedimentary rocks are created from the created from the EROSIONEROSION and and DEPOSITIONDEPOSITION of other of other rocks.rocks.

Formation of Sedimentary Formation of Sedimentary RocksRocks5 steps

◦ 1. Weathering – any process that breaks rocks into smaller pieces (sediment)

◦ 2. Erosion – the process of removing the sediments (wind, water, etc.)

◦ 3. Deposition – the dropping of sediments◦ 4. Compaction – squeezing layers of

sediments together◦ 5. Cementation – when dissolved minerals

seep into the tiny spaces between the sediments, cementing them into a solid rock

Strata = Layering of Strata = Layering of RockRock

Youngest Layers

Oldest Layers

Sedimentary Rocks are the Sedimentary Rocks are the ONLYONLY rocks that contain rocks that contain FOSSILSFOSSILS!!!!

There are 3 main types of There are 3 main types of Sedimentary RocksSedimentary Rocks

1. 1. Clastic Sedimentary Clastic Sedimentary RocksRocks

Rocks that break down under forces of nature - WIND and WATER!!

Made of pieces of other rocks

Examples of Clastic Examples of Clastic Sedimentary RockSedimentary Rock

Conglomerate

ShaleMade up of clay sediments

Examples of Clastic Examples of Clastic Sedimentary RockSedimentary Rock

2. 2. Chemical Sedimentary Chemical Sedimentary RocksRocksWater dissolves the minerals and

they come out of the solution (precipitate)

The mineral crystals grow together to make the rock

Examples of Chemical Sedimentary Examples of Chemical Sedimentary RockRock

Rock Salt (Halite)When water in ocean water

evaporates, leaving salt crystals behind

Limestone◦MOST COMMON ◦Found in caves◦Forms when calcium carbonate precipitates from a solution

Examples of Chemical Sedimentary Examples of Chemical Sedimentary RockRock

Made of things that were once living◦Plant materials◦Shells

3. 3. Bioclastic Sedimentary Bioclastic Sedimentary RockRock

Coal – made of plant remains

Coquina – made of shells

Examples of Bioclastic Sedimentary Examples of Bioclastic Sedimentary RockRock

Know how to read this for the Know how to read this for the TEST!!TEST!!

Identify the bioclastic sedimentary rock with the varied grain size.Coa

lIdentify the clastic sedimentary rock with the clay grain size.

Identify the crystalline sedimentary rock with halite composition.

Shale

Rock Salt

Identify the following Identify the following rocksrocksClastic with very fine grainCrystalline with dolomite

compositionBioclastic with carbon

composition and plants remainsClastic with rounded fragments

Write the characteristics of Write the characteristics of the following rocksthe following rocksBrecciaSiltstoneRock gypsumLime stone