Name: ____________________________ Block: _______________ Date: ________________
Classifying Common Sedimentary Rocks
Sedimentary rocks may be classified into three groups based on what they are made of
and how they were formed. If the sediments that make up the rocks came mostly from the shells
or body parts of living things, the rocks would be classified as organic sedimentary rocks. If the
sediments were produced from elements that were dissolved in water but later came out of
solution, the rocks would be classified as chemical sedimentary rocks. When elements come out
of solution, the elements are said to have precipitated and the process is called chemical
precipitation. Chemical sedimentary rocks are also called evaporites. If the sediments were
formed from particles that were weathered from other rocks, the rocks are called clastic
sedimentary rocks. Clastic sedimentary rocks are classified on the basis of the size of the
sediment particles that the rock is made of.
The char of common sedimentary rocks summarizes the characteristics of the primary
types of sedimentary rocks.
COMMON SEDIMENTARY ROCKS
Sedimentary Rock Type
Particle Size or Composition
Organic Sedimentary Rocks
Formed from the remains of living
mostly shells
things such as plants and animals
mostly plant remains
Chemical Sedimentary Rocks
Formed when elements that were
dissolved in water come out of
solution
Clastic Sedimentary Rocks
Formed when the particles that are
weathered from other rocks are
cemented together to form a new
rock (also called fragmental rocks)
Rock Name
Limestone
Coal
(bituminous)
Sediment particles too small to be
seen with the unaided eye
If the mineral material that comes
out of solution is
calcite
dolomite
halite
gypum
boulder-sized (greater than 256 mm)
cobble-sized (64 to 256 mm)
pebble-sized (2 to 64 mm)
sand-sized (0.06 to 2 mm)
clay-sized (less than 0.06 mm)
Limestone
Dolomite
Rock Salt
Gypsum
Conglomerate
Sandstone
Shale
Refer to the chart on the front to complete the following data table and answer the questions.
1. Fill in the sedimentary rock types and sedimentary rock name based on the description
provided in the data table.
DATA TABLE
Description
Sedimentary Rock Type
Rock Name
a. The sediment particles are formed by
chemical precipitation and are too small to see
with an unaided eye.
b. The sediment particles are mixtures of sizes
that range between 3.0 and 20.0 mm.
c. The sediment particles are pieces of shells
d. The sediment particles are sand-sized.
e. The sediment particles are mostly parts of
plants.
2. a. What sedimentary rock can be formed in two different ways? ________________________
b. Describe the two ways that this rock can form. ____________________________________
____________________________________________________________________________
____________________________________________________________________________
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3. What is the only sedimentary rock type that can be formed from things that were once alive?
______________________________________________________________________________
4. Table salt used to season foods is made of the mineral halite. What sedimentary rock is also
made of halite? _________________________________________________________________
5. How are clastic sedimentary rocks formed? ________________________________________
____________________________________________________________________________
6. Which three sizes of rock fragments produce conglomerate rocks? ______________________
____________________________________________________________________________
7. What size of particles produces shale? ____________________________________________
8. Sedimentary rocks are classified into three groups based upon:
a. __________________________________________________________________________
b. __________________________________________________________________________
9. What are organic sedimentary rocks? _____________________________________________
______________________________________________________________________________
10. What are chemical sedimentary rocks? __________________________________________
_____________________________________________________________________________