GEOLOGY
Geologists
1. Study the materials that make up the earth
and the processes that shape its surface
and interior.
2. Study the history of the Earth
3. Different types of geologists
a. Seismologists – study earthquakes
b. Volcanologists – study volcanoes
c. Mineralogists – study minerals
Topography
A. Definition - The shape of the land
1. Elevation – the height above sea level of a
point on Earth’s surface
2. Relief – the difference in elevation between
the highest and lowest parts of an area
3. Landform – a feature of topography such as a
hill or a valley formed by the process that shapes
Earth’s surface
a. Plain
b. Mountain
c. Mountain Range
d. Plateau
B. Longitude and Latitude
1. Longitude – the distance in degrees east or west of
the prime meridian
2. Latitude – the distance in degrees north or south of
the equator
C. Topographic Maps
Definition - is a map showing the surface features of an
area shown from above
1. Contour Line – connects point of equal
elevation
2. Contour Interval – change in elevation from
contour line to contour line
3. Index Contours – labels with the elevation in
round units
Minerals
A. Properties of Minerals
1. Naturally Occurring – found naturally, not
man made
2. Inorganic – the material was never living
3. Solid – definite volume and shape
4. Definite Chemical Composition – minerals
always contain the same elements, in the same
proportion!
5. Crystal Shape - particles in the mineral line up
in a specific order that repeats.
These properties make up the definition of a
mineral!
B. Identifying Minerals
1. Inspection
a. Color – not a reliable, impurities and
weathering can cause a change in color
b. Luster - the way a mineral reflects light. The
shine or lack of shine that a mineral possess.
1. Metallic – shines like a metal
2. Non-metallic - (glassy, waxy, dull, oily,
earthy, pearly)
2. Physical Tests
a. Streak - color of a powder left by a mineral
when rubbed on an unglazed tile.
b. Hardness - the resistance of a mineral to
being scratched
1. Compared to/using the Moh’s Hardness Scale
1. Talc – softest
2. Gypsum
3. Calcite
4. Fluorite
5. Apatite
6. Feldspar
7. Quartz
8. Topaz
9. Corundum
10. Diamond – hardest
“The guys can find any food quickly to chow down”
c. Cleavage - a minerals ability to split easily
along flat surfaces; it cleaves
d. Fracture - the way a mineral looks when it
breaks apart in an irregular way
e. Density – mass divided by volume; density
of a mineral doesn’t change no matter size of
mineral!
f. Specific Gravity - the ratio of the mass of a
substance to the mass of an equal volume of
water
SG = AW/LOSS
Loss = AW - WW
Example: A mineral has an air weight of 30
grams and a water weight of 20 grams. What is
the specific gravity of that mineral?
Loss = AW - WW
Loss = 30g – 20 g
Loss = 10 grams
SG = AW/LOSS
SG = 30g/10g
SG = ???????
What units???????
SG = 3
There are no units for
specific gravity! The
grams cancel!
C.
Mineral Formation
1. Crystallization of melted materials
2. Crystallization of materials dissolved in water
a. Hot water solutions – minerals dissolve in
hot water underground that is heated by
magma, the water begins to cool and the
minerals crystallize
b. Evaporation – when solutions on Earth’s
surface evaporate leaving minerals behind
D. Minerals and Magma
1. The rate at which magma cools, the
amount of gas, and the chemical
composition affect crystal size
2. The slower magma cools the larger
the crystals…the faster the magma
cools the smaller the crystals.
E.
Mineral Resources
1. Minerals are used for many everyday items
a. Talc – baby powder and makeup
b. Gypsum – building materials
c. Gold, Silver, Copper – jewelry and dental
procedures
2. Minerals are very important and they can
be depleted, so we must use them wisely
and recycle when possible.
A. Definition
Rocks
1. An element or combination of two or more minerals or
substances.
B. Three types of rocks
2. Igneous Rocks
a. Formed from the cooling and hardening of hot
molten material. Three classifications:
1. The slower the cooling, the larger the
crystal (mineral) grains – coarse-grained
2. The faster the cooling, the smaller the
crystal (mineral) grains – fine-grained
3. Cooling that is immediate forms no crystal
grains (sometimes holes) - glassy
Rocks continued…
b. Examples of igneous rocks
1. Granite – INTRUSIVE (formed by solidifying
underground)/Coarse-grained
2. Obsidian – EXTRUSIVE (formed by extreme
rapid cooling above ground)/ Glassy
3. Pumice – EXTRUSIVE (formed by extreme
rapid cooling above ground, holes)/ Glassy
4. Basalt – EXTRUSIVE (formed by rapid
cooling above ground)/Fine-grained
2. Sedimentary Rocks
a. Rocks formed from the erosion of existing rocks
and then the compaction and cementation of
sediment particles
1. Sediments – consists of rock fragments, plant
or animal remains, chemicals or minerals
Rocks continued…
2. Three classifications of sedimentary rocks:



Clastic – made of sediment from other rocks
Organic – made from sediment of living things
(plants and animals)
Chemical – made from the evaporation of water or
the precipitate of a certain mineral
b. Examples
1.
2.
3.
4.
5.
Conglomerate - clastic
Sandstone - clastic
Shale – clastic
Shell limestone – organic
Compact limestone - chemical
Rocks continued…
3. Metamorphic Rocks
a. Existing rock that undergoes some sort of
physical/chemical change
1. The change is usually due to extreme
heat and pressure deep within the Earth
2. Textures of metamorphic rocks
 Foliated – with layers or bands
 Unfoliated – NO layers or
bands/grains are randomly scattered
Rocks continued…
4. Examples of metamorphic rocks
1. Marble – unfoliated
2. Quartzite – unfoliated
3. Slate – foliated
4. Gneiss – foliated
5. Schist - foliated
4. The Rock Cycle
a. Summarizes the formation and breakdown of igneous,
sedimentary and metamorphic rock