ROCKS: Essay Review Questions for Test
1. In the rock cycle, igneous, metamorphic, and sedimentary
rocks can all become magma again. What step in the rock
cycle causes this to happen? Explain your answer.
The rocks must melt into magma and then they will cool and
form igneous rocks.
2. What is the relationship between an igneous rock’s texture
and where it was formed?
intrusive (underground) - cools slowly, coarse grained texture
(large crystals).
extrusively (above ground) - cools quickly, fine grained
texture (small crystals)
3. Why can water pass easily through sandstone but not
through shale?
The particles in sandstone are not as tightly compacted as the
particles in shale, so water can pass through the sandstone
easily.
4. Describe how a rock can form by evaporation. What type
of rock is it?
Chemical sedimentary rocks form when minerals are dissolved
in a solution and the solution evaporates. It will leave behind
crystals. (Ex: mineral deposits left behind when seas and
lakes evaporate)
5. How do the properties of a rock change when the rock
changes to metamorphic?
Everything about the rock will change - appearance, texture,
crystal structure, and mineral content because of the
tremendous heat and pressure.
6. What are the sources of heat that helps metamorphic
rocks form?
Tectonic plate movement can cause rock to be pushed down
into the heat of the mantle.
7. Use the information below about igneous rocks A-D to
classify each one as intrusive or extrusive and basaltic or
granitic. Fill in the chart with A, B, C, or D.
Rock A – dark-colored, large grains
Rock B – large crystals, high percentage of silica
Rock C – fine-grained texture, light–colored
Rock D – from Hawaiian volcano area, no visible crystals
Basaltic
Granitic
Extrusive
7. D
9. C
Intrusive
8. A
10. B
Basaltic – dark, little silica
Granitic – light, high silica
11. Describe the differences among detrital, chemical, and
organic rocks.
Detrital –bits and pieces of other rocks.
Chemical – minerals dissolve in a solution and crystallize
Organic – remains of plants and animals
12. What characteristics do geologists use to identify rocks?
Color, texture and determine its mineral composition.
13. Which would have large crystal, and igneous rock formed
form magma that cooled deep below the surface or an igneous
rock that cooled from lava on the surface? Explain why.
deep below the surface would have large crystals because the
magma cools slowly underground, so crystals grow very large
Use the diagram below to answer questions 14-16.
14. The letters in the boxes stand for the three major groups
of rocks. Identify those groups.
A – Igneous Rock
B – Sedimentary Rock
C – Metamorphic Rock
15. Describe how rock group C could change into rock group B.
A metamorphic rock could change into a sedimentary rock by
being weathered and eroded, then deposited in a new location,
then over time compaction and cementation forms a
sedimentary rock.
16. What forces drive this cycle?
Earth’s constructive and destructive forces drive the rock
cycle. These forces include: erosion, heat and pressure,
melting, and volcanic activity.
17. Name each diagram with the rock group it represents.
Metamorphic
Igneous
Sedimentary