Geology
Chapter 11 Guide
Name __________________________________________
Period __________
Read Section 11.1 and answer the following questions. READ THE SECTIONS – don’t just find the
answers and fill in the blanks.
11.1 – Mineral Resources
1. About how many minerals have been identified? ___________________________
2. When we run out of a mineral, will it be replaced by natural processes in our lifetimes? ____________
Formation of Ores
3. In what form are most minerals found in the earth’s crust? ______________________________________
4. What is an “ore”? ______________________________________________________________________
5. Describe how ores form in cooling magma. __________________________________________________
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6. How do ores form from contact metamorphism? ______________________________________________
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7. What is a “vein”? ______________________________________________________________________
8. What is a “lode”? ______________________________________________________________________
9. How does moving water help form ore deposits? ______________________________________________
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10. Name some minerals found in “placer deposits”. _____________________________________________
Uses of Mineral Resources
11. Read this paragraph and look at the table on p. 197. What are FIVE of the many uses of mineral
resources? ______________________________________________________________________________
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Mineral Conservation
12. What are two ways we might conserve minerals? ____________________________________________
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29. [NOT IN BOOK] What kinds of mineral resources do you think are mined in Minnesota? There’s one
major one (see sample of the ore on front table), but several other less well known ones. Take a guess.
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Geology
Section 11.2 Guide
Name __________________________________________
Period __________
Read Section 11.2 and answer the following questions. READ THE SECTIONS – don’t just find the
answers and fill in the blanks.
11.2 Fossil Fuels
13. What is a fossil fuel? ___________________________________________________________________
14. *** KNOW THIS ***What are the three main fossil fuels? __________________________________
15. Where does the energy in fossil fuels come from originally? ____________________________________
Coal
16. How is coal formed? ___________________________________________________________________
18. What kind of rock is anthracite coal (igneous, sedimentary, or metamorphic)? _____________________
Why do you say this? _____________________________________________________________________
Petroleum and Natural Gas
19. What do we usually call “petroleum”? ____________________________
20. How are petroleum and natural gas formed? ________________________________________________
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21. What kind of rock is petroleum usually found in? ____________________________________________
Why this type of rock? ____________________________________________________________________
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Uses of Fossil Fuels
22. Look at the graphs on p. 201. What is the main use of coal? ____________________________________
23. What are the main uses of petroleum products? ______________________________________________
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24. What is a “petrochemical”? ______________________________________________________________
25. Are fossil fuels “renewable”? _______ Why or why not? ______________________________________
_______________________________________________________________________________________
26. Which of the main fossil fuels is most common? _____________________________________________
27. About how long will our coal supplies last? ____________________________
28. What are some of the environmental problems associated with use of fossil fuels? Name at least three.
(read the entire section on p. 201)
_______________________________________________________________________________________
_______________________________________________________________________________________
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Mining in Minnesota
What's mined in Minnesota?
Map of minerals mined in Minnesota. Are any minerals mined in the county where you
live? Which ones?
Minnesota is the largest producer of iron ore and taconite in the United States. Even
though nearly all of the high grade natural iron ore in Minnesota has already been mined, advances in
technology have found a use for lower grade iron ore, called taconite. The taconite is crushed, processed into
hard, marble-sized pellets, and shipped to steel mills. The taconite pellets are melted in blast furnaces and
then blown with oxygen to make steel. Minnesota currently has seven operating taconite plants which make
the pellets. About 44 million tons of taconite pellets were shipped from the state in 1996. That's enough to
fill over 500,000 railroad cars! In the past, iron ore was mined on three iron ranges - the Cuyuna, Mesabi
and Vermilion - and also in Fillmore County in southeastern Minnesota. Today, only the Mesabi Range still
has iron ore/taconite mining taking place.
Clay is mined in the Minnesota River Valley. Clay is used in making bricks, porcelain, tiles, and medicines.
Companies are currently exploring Minnesota for higher grade kaolin (KAY-a-lin) clay, which is a fine,
white clay used to add a glossy look to paper. Today, Georgia is the largest producer of kaolin clay in the
United States.
About 11,000 years ago, glaciers covered Minnesota. These glaciers left behind large amounts of sand and
gravel. There are sand and gravel mining operations in nearly every county in Minnesota. You may not think
of sand and gravel as a valuable resource, but without it concrete could not be made. Highways, roads,
bridges and many buildings are made of concrete. Sand is also used along with salt to melt ice on roads and
to provide better traction in the snow.
Silica sand is a very fine sand composed of quartz (a white to colorless mineral) and is mined in the
southeastern part of Minnesota. It is used to make glass, as a source of silicon, and is used in oil drilling to
improve the flow of oil to oil wells.
Granite and limestone are used in the construction of homes, buildings, roads and tombstones. These rocks
are often mined in large blocks from a quarry. When granite or limestone is mined this way, it is called
dimension stone. Look at the buildings in your town. Are any made with limestone or granite?
Peat is formed by partially decomposing plant material in wet environments, such as bogs or fens, where
more plant material is produced than is decomposed. If peat is a plant, how can it be a mineral? Peat is the
beginning of the fossilization of the plants. Fossil fuels, such as coal, began as plant material too. Peat is used
mainly in the gardening industry, but it is also used for compost, turkey litter, absorbing oil, and fuel. Next
time you are in the gardening store, look for peat.
These are the only minerals currently mined in Minnesota. Manganese, copper, nickel, and titanium have
also been discovered in the state in minable quantities, but are not of high enough quality under today's
prices to mine profitably. Exploration for additional resources, such as gold, platinum, diamonds, zinc, and
lead, continues today in Minnesota.
Digging into Minnesota Minerals
Excerpts
from a
Publicatio
Can you believe these things happened in Minnesota? Rocks can tell us a
n from
lot about what happened in Minnesota long ago. They show a history of
the DNR
volcanoes, seas, mountain ranges, earthquakes, and glaciers. Let's take a look
Division
at how the rocks show us that these events happened!
of Lands & Minerals
VOLCANOES! EARTHQUAKES! GLACIERS!
Volcanoes
Volcanic action creates lava and ash. The rocks along Minnesota's North Shore of
Lake Superior, for example, were created from cooling lava. Bentonite clay in
southeastern Minnesota was formed from volcanic ash.
Earthquakes
Besides eyewitness accounts of earthquakes in Minnesota, geologists look at rock
layers for evidence of these events. They can see that different layers do not always lay flat on top of one
another. There are folds and breaks. The shifting of the earth (known as earthquakes) caused the layers to
move.
Geologists can also see evidence of earthquakes in Minnesota with the Midcontinental rift. This rift, running
from Minnesota to Kansas, is the result of the middle of the North American continent splitting apart. Rifting
is the opposite of a mountain range forming. Instead of rock material being pushed up to form a mountain,
rock material falls down when a wide split in the land is made. Molten material from deep within the earth
rises up to fill in the gap.
Mountains
Geologists see patterns in rock layers and fault zones showing that rock layers were pushed on top of other
layers. Geologists see this same pattern today with the Rocky Mountains. So, they hypothesize, these layers
of rock were once mountains. But what happened to them? The mountains have been worn away by millions
of years of exposure to rain, gravity, wind and ice.
Seas
Geologists know Minnesota was once covered by seas since they have found limestone formed from pieces
of shell; sandstone from beach sands; and shale from deep water mud. The Mesabi Iron Range marks the
shoreline of an ancient sea. Fossils of shells, fish and other marine life have been found along parts of the
Mesabi Iron Range.
Glaciers
Glaciers left behind many signs of their existence in Minnesota. Deep scratches are found on slabs of rock,
showing that the glacier passed by. Large amounts of sand, gravel, and rock were left behind when the
glaciers began to melt. This material is called glacial drift. In Minnesota, glacial drift covers the bedrock (the
solid rock under the crust of the earth). Since the bedrock is buried under the glacial drift, geologists cannot
look directly at it to see what kind of rock it is. Many features in Minnesota's landscape, such as most lakes,
hills, and ridges, were formed by glacial activity.
The surface of our earth is still changing!
The wearing away of the surface is called erosion. Erosion constantly attacks the land by wind, water, frost,
and temperature changes. Bedrock breaks into big rocks, and big rocks break into small rocks and soil; rocks
and soil are moved to different locations, usually by running water. Our land is being eroded and changed
everyday. How can we tell this is happening? We see dust in the air. Streams have muddy water. Potholes
appear in our streets. These are all signs of erosion.
Taconite
Taconite is a low-grade iron ore. When the high-grade natural iron ore was plentiful, taconite was
considered a waste rock and not used. But as the supply of high-grade natural ore decreased, industry began
to view taconite as a resource. Dr. E.W. Davis of the University of Minnesota, along with other scientists and
engineers, conducted years of laboratory tests and experiments to find a way to take the iron ore out of the
taconite rock. After many years of hard work, a process was developed to create taconite pellets. Taconite
saved Minnesota's iron ore mining industry.
The Hull Rust Mahoning Mine in Hibbing, Minnesota
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World's largest open pit iron ore mine
First ore shipments in 1895 (still being mined today,
100 years later)
Originally 30 separate mines
Total area: 1,591 acres
Total length: 3 1/2 miles
Greatest width: 1 1/2 miles
Greatest depth: 535 feet
Total ore shipped: About 1 billion tons Total rock
removed: About 2 billion tons (that's 4 trillion pounds!)
Let's look at how the taconite pellet process works.
1. Blasting
Taconite is a very hard rock. Using explosives, the taconite is blasted into
small pieces.
2. Transportation
The taconite pieces are scooped up by electric shovels. Each shovel can hold up to 85 tons of rock! The
shovels place the taconite into giant dump trucks. These trucks are as big as a house and hold up to 240 tons
of taconite. The trucks take the taconite directly to the processing plant, if it is nearby, or to train cars if it is
far away.
3. Crushing
At the processing plant, the taconite is crushed into very small pieces by rock
crushing machines. The crushers keep crushing the rock until it is the size of a marble. The rock is mixed
with water and ground in rotating mills until it is as fine as powder.
4. Separation
The iron ore is separated from the taconite using magnetism. The remaining
rock is waste material and is dumped into tailings basins. The taconite
powder with the iron in it is called concentrate.
5. Pellets
The concentrate (the wet taconite powder) is rolled with clay inside large
rotating cylinders. The cylinders cause the powder to roll into marble-sized balls. (This is like rolling wet,
sticky snow into balls to make a snowman). The balls are then dried and heated until they are white hot. The
balls become hard as they cool. The finished product is taconite pellets.
6. Steel
The taconite pellets are loaded into ore ships. These ships sail on the Great
Lakes to Gary, Indiana, Cleveland, Ohio and other steel-making towns. The
taconite pellets are brought to the steel mills to be melted down into steel.
Taconite is mined from the Mesabi Iron Range, near Hibbing, MN. Then it is processed into pellets and
moved by train--or on ore boats from Duluth--to ports and steel mills around the Great Lakes region.
Taconite process photos courtesy American Iron Ore Association and Hibbing Taconite.