Classwork
Name ______________________________________________
Block ______
Sedimentary Rock Lab
Step I – Sketch
All sedimentary rocks come from sediments. Some sedimentary rocks are
called clastic because they are made of rock fragments. These fragments can be
as small as microscopic clay particles or as large as boulders. The type of rock
that forms is the result of the sorting of sediments that occurs when sediments
are eroded and deposited elsewhere.
Look at the diagram on page 127. Copy the diagram below. Be sure to
include the following labels: conglomerate, sandstone, shale, sand/gravel, sand,
silt/clay, an arrow to show the flow of the river, and an arrow to show the
direction of sorting from largest particle size to smallest particle size.
Classwork
Step II – Shake It Up!
Obtain a cylinder filled with water, sand, pebbles, and silt.
1. Make a prediction, what order will the sediments fall to the bottom
of the cylinder?
1st2nd3rdShake the cylinder by turning it gently upside down and then right side
up.
2. Which sediment was the first to settle? Why?
Pebbles because they are heavier
3. Which sediment was the last to settle? Why?
Sand because it is light
4. Imagine this cylinder was actually a moving stream, which sediment
will stay suspended longer in the stream, floating along with the
current?
Sand
5. Continue to imagine the cylinder as a stream, which sediment will
roll along the bottom of the river as the current moves it?
Pebbles
6. What will happen to the shape of these large pieces if the water
continues to move them?
Rounded
7. What has to occur in order for sediments to settle out of a moving
river? (hint: the sediments began to settle in the cylinder once we
stopped shaking it)
River has to lose energy when it meets a larger body of water.
Classwork
Step III – Read and Answer Chapter 6, Section 3
1. According to the sorting of sediments diagram, what types of sediments
make up conglomerates?
Sand and gravel
2. According to the sorting diagram, which sediments consist of the smallest
particles?
Silt/Clay
3. According to the sorting diagram, how would the texture of conglomerates
compare to that of shales?
Conglomerates would be rough and shale would be smooth.
4. From where a stream runs into a lake and out to the middle of that lake,
in what order would you most likely find the three basic types of clastic
sedimentary rock?
When a stream loses energy, sediments are deposited. Gravel, pebbles & sand
5. What is cementation?
When minerals fill the spaces between sand grains , pebbles or other rock
particles, they bind the fragments together
6. What does it mean to say that the minerals precipitate?
When minerals precipitate out of solution
Chemical action – ions combining to form new minerals
7. What happens during evaporation? How do minerals form during this
process?
A solution with dissolved minerals evaporates leaving behind the minerals.
8. How do organic limestones form?
Certain organisms produce carbonate shells or other support structures such as
coral. When the organisms die, their calcium rich remains pile up on the ocean
floor and the sedimentary rock is formed from these deposits.
9. Which process formed the rock salt flat in the photograph on page 129?
Chemical process - evaporation
10.Which sedimentary rock has an organic form as well as a chemical form?
Limestone
Classwork
Step IV – Identify
Fill in the chart using the rock samples and your book. If there is more
than one blank, then you are looking for more than one sample. You should
consider the following samples:
31, 32, 33, 37, 39, 40, 41, 42, 45, 48, 50, 51, 52, 54, 55, 56, 59, 63, 64, 68, 69
Sedimentary Rocks
Clastic
Chemical
Organic
Conglomerates - Sand
and round gravel
cemented together,
sediment size varied
a.__31__________
b.__32__________
c.__33__________
Sandstones – Sand-sized
grains compacted and
cemented together
a.__39__________
b.__41__________
c.__42__________
Rock salt – rock form of
halite, reddish to tan in
color (formed from
evaporation)
a.__63_________
Coal – black, made from
fossilized plant material
a.__69________
Rock gypsum – rock
form of gypsum, pink to
tan on color, powered
sugar appearance
(formed from
precipitation)
a.__64__________
Dolomite – pink to tan
color, crystal visible on
surface (formed from
evaporation)
a. __59_______
Fossil limestone – pieces
of shells cemented
together
a.__54_________
b.__55_________
c.__56_________
Chemical limestone –
light in color, very dense
a. __52______
Coquina – pieces of
shells compacted
together (very little other
material)
a. __40_________
Shales and claystone–
clay-sized grains invisible
to the naked eye
a.__45___________
b.__48___________
c.__50___________
d.__51___________
Breccia – light-color,
sand and irregular
pebble fragments
a.__37__________
Chalk – white, used to
write on slate
a.__68__________