Name: _____________________________
Period: _____ Date: _________________
ACTIVITY: Rocks and Minerals
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 cam mostly from the shells or body
part of living things, the rocks would b classified as organic sedimentary rocks. If the sediments
were produced from elements that were dissolved the water buy late 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 evaporates. 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 chart of common sedimentary rocks summarizes the characteristics of the primary types
of sedimentary rocks.
Common Sedimentary Rocks
Sedimentary Rock Type
Particle Size or Composition
Rock Name
Organic Sedimentary Rocks
Formed from the remains of living things
such as plants and animals
Mostly shells
Limestone
Mostly plant remains
Coal
(bituminous)
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)
Sediment particles too small to be
seen with unaided eye
If the mineral material that come our
of solution is:
Calcite
Dolomite
Halite
Gypsum
Limestone
Dolomite
Rock Salt
Gypsum
Boulder-sized (greater than 256mm)
Cobble-sized (64 to 256 mm)
Pebble-sized (2 to 64mm)
Sand-sized (0.06 to 2 mm)
Clay-sized (less than 0.06mm)
Conglomerate
Conglomerate
Conglomerate
Sandstone
Shale
Refer to the chart to complete the following Data Table and answer the questions.
1. Fill in the sedimentary rock types and sedimentary rocks described 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 sandsized.
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.
_________________________________________________________________
_________________________________________________________________
_________________________________________________________________
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? ___________________________
Adapted from Prentice Hall, Inc.
58
Chapter 13