APES Chapter 15 Geology and Nonrenewable Mineral Resources
Exam Study Guide
The asthenosphere is a relatively thin plastic layer contained in a much larger region
known as the mantle. The mantle is the solid portion of the Earth's interior that is located
between the bottom of the Earth's crust (at about 15 mi or 25 km depth) and the top of the
liquid outer core (at 1800 mi or 2900 km depth).
The layers in the mantle that are above and below the asthenosphere are known as the
lithosphere and the mesosphere respectively.
The lithosphere is broken into 12 major tectonic plates that possess much greater
mechanical strength than the underlying asthenosphere.
The theory of plate tectonics explains the occurrence of earthquakes, volcanoes,
mountains, ocean trenches and movement of the earth’s plates. Tectonic plates move on
the astheosphere.
Tectonic plates move apart in opposite directions at divergent plate boundaries and come
together at convergent plate boundaries. Tectonic plates move apart in opposite but
parallel directions along fault at a transform fault. Earthquakes are most directly caused
by the creation of a fault ( fracture of a rock) or shifting along an existing plate. The
energy sources primarily responsible for earth’s external geological processes are energy
from the sun and gravity.
Within the earth’s crust we find many types of rocks and minerals. A mineral has crystal
structure, occurs naturally, and is an inorganic solid. The change of rocks from one type
to another is known as the rock cycle. – Igneous, metamorphic and sedimentary
Igneous rocks are important sources of many non-fuel mineral resources.
Limestone is a sedimentary rock formed from compacted shells and skeletons. Lignite
and bituminous coal are sedimentary rocks formed from the remains of compacted plants.
Sedimentary rocks cover most of the earth’s land surface.
Heat and pressure convert sedimentary rock into metamorphic rock. Slate, anthracite and
marble are examples of metamorphic rocks.
We define a rock or mineral reserve as resource that can be identified and profitably
extracted. Subsurface mining is more dangerous than surface mining. Surface mining
disturbs more. Mining can cause collapse of land, acid mine drainage, spoil heaps and
tailings and emissions of toxic chemicals. Acid mine drainage may contaminate ground
water. Runoff from underground mines may carry sulfuric acid. Waste soil and rock
removed during surface mining is called spoil. The fraction of the ore containing waste
minerals is called gangue. When ore undergoes processing, a waste called tailings.
Smelters ( melting or baking) of the ore give off soot, lead, and sulfur dioxide.
Environmental impact is the greatest mining for low-grade ore.
What is a low-grade ore? What is a high grade ore? Some examples of economically
valuable minerals and their use in our society.
The U.S. Mining Law of 1872 and revision to the
-makes companies responsible for restoring the land.
-requires mining companies to pay 12.5% royalty on any hard-rock minerals they extract.
- make mining companies pay for environmental clean-ups resulting from mining
activities.
- make companies pay for damage resulting from mining activities.
Nodules of manganese are found on the floor of the deep ocean. These manganese rich
nodules are an attractive resource because they often contain several other economically
valuable minerals.
When a resource has been economically depleted we can
1. recycle or reuse what has already been extracted.
2. cut down on unnecessary waste of the resource.
3. find a substitution
4. just do without it
Depletion time is the time it takes to use up about 80% of the mineral reserves at a given
rate. A depletion curve is typically used to project the depletion time for a resource.
One of three objective questions.
1. Describe how
mineral resources can be used more sustainably. Summarize the
nanotechnology revolution and its implications.
2. Distinguish between internal and external geologic processes. Discuss how these
processes affect human activities and natural ecosystems.
3. Describe the economics of nonrenewable minerals. Explain the limitations of mining
lower-grade ores. Discuss the option of getting more minerals from the ocean.
Free Response Question If you have read your objective questions and use study guide to
prepare for the exam you will be able to answer the free response question. If there is
something in the study guide that you don’t understand then be sure to use your book to
clarify the concept.