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EARTH & SPACE
SCIENCE
Chapter 7 Resources and Energy
7.1 Mineral Resources
7.1 Mineral Resources Objectives
Explain what ores are and how they form.
Identify four uses for mineral resources.
Summarize two ways humans obtain
mineral resources.
Introduction
The Earth’s crust contains over 3,000 minerals
that have taken millions of years to form.
Many of the minerals of the Earth’s crust are
mined for human use.
Minerals can be metal (gold, copper, or
aluminum, etc.) or non-metal (sulfur, talc, quartz,
etc.).
Metals are good conductors of heat and
electricity and are malleable and ductile.
Ores
An ore is a mineral deposit from which a metal
or nonmetal resource can be mined for a profit.
For example, one can mine hematite and
limonite and extract the iron from them for a
profit.
Metallic minerals that exist in the pure form in
nature, such as copper, gold, and silver, are
called native elements.
Ores can form in a variety of ways.
Ore and Native Elements
Cooling Magma
As magma cools, dense metallic minerals
sink.
Layers of metallic minerals accumulate at
the bottom of the magma chamber to form
ore deposits.
Examples include chromium, nickel, and
lead ores.
Contact Metamorphism
Contact metamorphism is a process that occurs
when magma comes into contact with existing
rock.
The composition of the surrounding rock is
changed by heat and chemical reactions with
the hot fluids from the magma.
As hydrothermal fluids move through small
cracks in large masses of rock, they can
dissolve minerals from the surrounding rock.
Contact Metamorphism
Over time, those minerals precipitate from
the solution and form narrow zones of rock
called veins.
Veins are often ores of valuable heavy
minerals such as gold, tin, lead, and
copper.
A lode is a relatively rich mineral deposit in
a rock formation.
Moving Water
As rocks break down from weathering, tiny
fragments of native elements may be released.
Streams can carry these fragments until the
current becomes too weak to carry the heavy
metals.
These fragments become concentrated along
the stream bottom in areas known as placer
deposits due to the mechanical action of the
stream.
Uses of Mineral Resources
Some metals are prized for their beauty and
rarity, such as gold, silver, and platinum.
Other metals are used as conductors in
electronics such as copper or as structural
material such as aluminum in airplanes.
Some minerals, like diamonds and emeralds,
may be considered gemstones, material that can
be used as ornament when cut or polished.
Uses of Mineral Resources
Minerals such as
calcite and gypsum
may be used in
building materials.
Sulfur is used in the
manufacture of some
antibiotics,
gunpowder, and
rubber.
Resources
Hematite Streak http://earth.geol.ksu.edu/sgao/g100/plots
Native Copper http://www.nps.gov/kewe/CooperatingSites
.htm
Native Gold - http://www.arizona-goldprospecting.biz/
Drywall http://www.answers.com/topic/drywall