Download Multiple Choice: Read each item below and choose the best answer

Geology Part 2 Test- Study Guide Key
Test Date: December 11, 2015
1.) Minerals
A. What characteristics must all minerals have to be
classified a mineral?
Is it nonliving (inorganic) material? Is it a solid? Does it
have a crystalline structure? Is it formed in nature?
Does it have the same composition throughout?
B. How do you identify an unknown mineral?
Color (not best choice), Luster (metallic or nonmetallic),
Streak color, Hardness, Break (cleavage or fracture), and
other special properties.
C. What is Moh’s Scale? What do the numbers on the scale
mean?
Determines the hardness of a mineral as an identification
tool.
The numbers represent the level of hardness, as
compared to other minerals, when scratched. A mineral
can scratch any other mineral beneath it, but not above
it.
2. Rocks
A. What are the three classifications of rocks?
Igneous, Sedimentary, and Metamorphic
How is each rock type formed? Sedimentary rocks form
from rock and mineral fragments forming layers, then
compacting and cementing (Weathering, Erosion,
Deposition, Compacting, Cementing, and Time).
Igneous Rocks are formed from magma (intrusive) or lava
(extrusive) that cools and hardens.
Metamorphic rocks are created from rocks that have
changed through heat and pressure.
B. What are some characteristics and examples of each
rock type?
Igneous- granite, basalt, obsidian (fine or coarse
grained/small or large crystals depending on how fast the
magma/lava cooled/ Sometimes porous.
Metamorphic- Marble , quartzite, slate, gneiss (foliated
bands)
Sedimentary –sandstone, conglomerate, shale (mineral
fragments are cemented together, minerals crystallize
out of a solution to give fine grains, can have organic
material. LAYERS! You can feel the sediments – gritty.)
C. What are the stages of the rock cycle?
Know page 92-93 in book. Rock cycle can go in any order.
Any rock can change properties over time to become
another class of rock. Rock cycle includes melting,
cooling, weathering, deposition, compaction and
cementation, pressure, etc.
3. Weathering, Erosion, and Deposition:
A. What is mechanical and chemical weathering?
Mechanical—physically breaks rock into smaller pieces
Chemical—chemically changes the minerals that make up
the rock
B. What are agents of mechanical and chemical weathering?
Examples:
abrasion- ___mechanical (Wind, water, gravity)
ice wedging-___mechanical (Ice)
rust-____chemical (Air)
limestone cave formation- ______chemical (Acids in
Ground Water)
lichens- _____chemical (Acids in Living Things)
C. What are weathering, erosion and deposition?
Weathering: breaking down of rock particles
Erosion: movement or transporting
Deposition: dropping or depositing
D. What type of climate is associated with mechanical
weathering?
Cold, wet climates (think ice wedging and potholes in roads)
4. Fossils
A. In which rock type would you find fossils? sedimentary
B. What is the difference between an index and trace
fossil?
Index fossils: Fossil remains of an extinct, short-lived
organism that geologists use to begin a new geological time
period or used to date the layers of rock (indicator).
Trace fossils: imprints of an organism (ex. footprints)
C. What can fossils teach about the earth’s history?
Environmental changes, how an organism lived and died,
dating of rock layers, what life was like during a certain
time period.
D. What is the principle of superposition?
The law that states the top layer of undisturbed
sedimentary rock will be younger than the bottom layers of
rock.
5. Soil
A. What is soil? A loose mixture of rock fragments, organic
material, water, and air that can support the growth of
vegetation. It is mostly made of weathered rock.
B. What are the different layers of soil? (Text page 290)
A – Topsoil – nutrient rich
E – Leaching layer – minerals leach out of this layer with water
as it passes thru
B – Subsoil – mineral rich – sand and clay
C – Regolith – no organic material reaches this layer, broken
pieces of bedrock
R – Bedrock – solid rock
D. How do humans positively and negatively affect soil
erosion? Negatively: Poor farming practices, less trees being
planted, construction, etc…
Positively: Replanting of trees, silt fences, better farming
practices (terracing, etc…)