Chapter 3-3
Sedimentary Rocks
1. Define sediment: small solid pieces of material that come from rocks or living things
2. Define sedimentary rock: a type of rock that forms when particles from other rocks or
the remains of plants and animals are pressed and cemented together.
Sedimentary rock forms through the processes listed below. Describe each process.
1. EROSION: wind or water loosen fragments of rock and carry them away
2. DEPOSITION: as wind and water slow or stop, sediments settle out
3. COMPACTION: thick layers of sediments build up and press down on the layers
beneath them
4. CEMENTATION: minerals in the sediment dissolve in water and fill in the spaces
between the particles cementing the particles together
There are three major categories of sedimentary rock. Complete the table below
SEDIMENTARY ROCKS
ROCK TYPE
CLASTIC
DESCRIPTION
Rock fragments are squeezed and
cemented together. Particles range
from microscopic to boulder size.
EXAMPLES (EXPLAIN FORMATION)
SHALE: tiny particle of clay layer
and are squeezed together. Forms
smooth, flat rock. Water cannot pass
through
SANDSTONE: sand is compacted and
cemented together. May contain
small holes which absorb water.
CONGLOMERATE OR BRECCIA: Mix
of large and small rock fragments.
Conglomerate=rounded
Breccia= sharp edges
ROCK TYPE
ORGANIC
DESCRIPTION
Remains of plants and animals are
deposited in thick layers
EXAMPLES (EXPLAIN FORMATION)
COAL: remains of plants that build
up into layers
LIMESTONE: Shells of animals pile
up as sediment on the ocean floor.
Pressure compacts lower layers.
Some shells dissolve and the calcite
combines with water to form a
cement.
Chalk is a form of limestone
CHEMICAL
LIMESTONE: Calcite dissolves in
water and forms a solution. When
water evaporates it forms limestone.
ROCK SALT: Forms when sea water
evaporates, leaving salt behind.
How and why are sedimentary rocks used? Sedimentary rocks are soft enough to be cut into
blocks or slabs that are used in buildings.
Limestone is also important in the smelting process.