Download Sedimentary Rocks

Sedimentary Rocks
Sedimentary Rocks are #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
created from the EROSION
and DEPOSITION of other
rocks.
Formation of Sedimentary Rocks

5 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 Rock
Youngest Layers
Oldest Layers
Sedimentary Rocks are the ONLY
rocks that contain FOSSILS!!
There are 3 main types of Sedimentary Rocks
1. Clastic Sedimentary Rocks
Rocks that break down under forces of
nature - WIND and WATER!!
 Made of pieces of other rocks

Examples of Clastic Sedimentary Rock
 Conglomerate
Examples of Clastic Sedimentary Rock
 Shale

Made up of clay sediments
2. Chemical Sedimentary Rocks
Water dissolves the minerals and they come
out of the solution (precipitate)
 The mineral crystals grow together to make
the rock

Examples of Chemical Sedimentary Rock
Rock Salt (Halite)
When water in ocean water
evaporates, leaving salt crystals behind
Examples of Chemical Sedimentary Rock

Limestone
◦ MOST COMMON
◦ Found in caves
◦ Forms when calcium
carbonate precipitates from
a solution
3. Bioclastic Sedimentary Rock

Made of things that were once living
◦ Plant materials
◦ Shells
Examples of Bioclastic Sedimentary Rock

Coal – made of plant remains

Coquina – made of shells
Know how to read this for the TEST!!
Identify the bioclastic sedimentary rock with the varied grain size.
Coal
Identify the clastic sedimentary rock with the clay grain size.
Shale
Identify the crystalline sedimentary rock with halite composition.
Rock Salt