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Day 2
When someone says a rock has fine grains
or coarse grains, what are they talking
about?
Grains are the particles that make up a
rock. The words fine and coarse refer to
the size of the grains. Fine grains are
small, and coarse grains are larger.
What is molten rock?
Molten rock is melted rock.
Daily Warm-Up Exercises
1
Trilobite Hunter, Part 2
Introduction to the Grand Canyon
Earth History, Investigation 8
2
Return to Trilobite Hunter
Are igneous rocks good for finding
trilobite fossils?
granite
pumice
No, because they are made of molten rock,
which is much too hot to preserve organisms.
3
Return to Trilobite Hunter
We are now going to look at a second type of
rock, called metamorphic. We’ll find out if
metamorphic rocks are good for finding fossils.
These rocks are found in some of the deepest
layers of the Grand Canyon.
4
Compare Rock Types
Contrasting Case Activity 1, Part 2
Earth History, Investigation 8
Compare Rock Types
5
List Observable Features
Metamorphic #1
Metamorphic #18
List the features you
can observe about the
two metamorphic rock
samples.
Compare Rock Types
6
Which is Which?
1
18
Can you figure out
which rock is
schist and which
is quartzite?
Compare Rock Types
7
What’s the Same? What’s Different?
1
18
Identify similarities
and differences and
write them in the
Venn diagram.
Compare Rock Types
8
Metamorphic
Schist Only
Both Schist & Quartzite
Quartzite Only
Fairly shiny
Rough
Dull and hard
Medium to coarse
grain size
Made of minerals
Fine grain size
Crystals are flat and
arranged in layers
Formed when a rock
changes due to heat and/or
pressure
Grains appear to be
fused together
Formed from slate, a
metamorphic rock
Formed deep beneath
Earth’s surface
Compare Rock Types
Formed from
sandstone, a
sedimentary rock
9
Return to Trilobite Hunter
Are metamorphic rocks good for finding
trilobite fossils?
schist
quartzite
Not very good because the heat and/or pressure
will usually destroy any fossils contained in the
original rock.
10
Return to Trilobite Hunter
Let’s look at one more type of rock,
sedimentary. We’ll find out if sedimentary rocks
are good for finding trilobite fossils.
11
List Observable Features
Sedimentary #7
List the features you can
observe about the two
sedimentary rock samples.
Sedimentary #8
Compare Rock Types
12
Which is Which?
7
8
Can you figure out
which rock is shale
and which is
sandstone?
Compare Rock Types
13
What’s the Same? What’s Different?
7
8
Identify similarities
and differences and
write them in the
Venn diagram.
Compare Rock Types
14
Sedimentary
Shale Only
Both Shale &
Sandstone
Sandstone Only
Smooth
Dull and hard
Very fine grain size
Grains are arranged in
layers
Formed from particles
of silt or clay
Rough
May contain fossils
Made of minerals
Formed when something
gets compacted and
cemented together
Medium to coarse
grain size
Formed from grains
of sand
May form on or below
Earth’s surface
Compare Rock Types
15