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Resources and Energy Section 1 Ores Mineral resources can be either metals, such as gold, Au, silver, Ag, and aluminum, Al, or nonmetals, such as sulfur, S, and quartz, SiO 2. Metallic minerals such as gold, silver, and copper, Cu, are called native elements and can exist in Earth’s crust as nuggets of pure metals. Most other minerals in Earth’s crust are compounds of two or more elements.
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Resources and Energy Section 1
Section 1: Mineral ResourcesPreview
• Key Ideas
• Ores
• The Formation of Ores and Placer Deposits
• Uses of Mineral Resources
• Mineral Exploration and Mining
• Comparing Metals, Nonmetals, and Metalloids
Resources and Energy Section 1
Key Ideas
• Explain what ores are and how they form.
• Identify four uses for mineral resources
• Summarize two ways humans obtain mineral resources
Resources and Energy Section 1
Ores• Mineral resources can be either metals, such as gold,
Au, silver, Ag, and aluminum, Al, or nonmetals, such as sulfur, S, and quartz, SiO2.
• Metallic minerals such as gold, silver, and copper, Cu, are called native elements and can exist in Earth’s crust as nuggets of pure metals.
• Most other minerals in Earth’s crust are compounds of two or more elements.
Resources and Energy Section 1
Ores, continued
• ore a natural material whose concentration of economically valuable minerals is high enough for the material to be mined profitably.
Ores Formed by Cooling Magma
• Some ores, such as chromium, Cr, nickel, Ni, and lead, Pb, form as the magma cools and the dense metallic minerals sink.
• As the minerals sink, layers of these minerals accumulate at the bottom of the magma chamber to form ore deposits.
Resources and Energy Section 1
Ores, continued
Ores Formed by Contact Metamorphism
• Some ores of lead, copper, and zinc, Zn, form through the process of contact metamorphism.
• Contact metamorphism is a process that occurs when magma comes into contact with existing rock.
• Heat and chemical reactions with hot fluids from the magma can change the composition of the existing rock.
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Ores, continued
Ores Formed by Contact Metamorphism, continued
• Ore deposits may also form when hot fluids called hydrothermal solutions move through small cracks in a large mass of rock.
• Minerals from the surrounding rock dissolve into the solution. Over time, new minerals precipitate from the solution and form narrow zones of rock called veins.
• When many thick mineral veins form in a relatively small region, the ore deposit is called a lode.
• lode a mineral deposit within a rock formation.
Resources and Energy Section 1
Ores, continued
Ores Formed by Moving Water
• The movement of water helps to form ore deposits.
• Tiny fragments of native elements, such as gold, Au, are released from rock as it breaks down by weathering.
• Streams carry the fragments until the currents become too weak to carry these dense metals, which collect in placer deposits.
• placer deposit a deposit that contains a valuable mineral that has been concentrated by mechanical action
Resources and Energy Section 1
The Formation of Ores and Placer DepositsThe diagram below shows how ores form in placer deposits.
Resources and Energy Section 1
Uses of Mineral Resources• Metallic ores are sources of valuable minerals and
elements, like gold, Au, platinum, Pt, and silver, Ag.
• Certain nonmetallic minerals display extraordinary brilliance and color when they are specially cut for jewelry.
• gemstones a mineral, rock, or organic material that can be used as jewelry or an ornament when it is cut and polished.
• Other nonmetallic minerals, such as calcite and gypsum, are used as building materials.
Resources and Energy Section 1
Mineral Exploration and Mining
• During mineral exploration, people search for mineral deposits by studying local geology.
• Airplanes that carry special equipment are used to measure and identify patterns in magnetism, gravity, radioactivity, and rock color.
• Exploration teams also collect and test rock samples to determine whether the rock contains enough metals to make a mine profitable.
Resources and Energy Section 1
Mineral Exploration and Mining, continuedSubsurface Mining• Miners work underground to recover mineral deposits located below
Earth’s surface using the subsurface mining method.Surface Mining• Surface mining strips overlying rock material to reveal mineral
deposits that are located close to Earth’s surface.Placer Mining• In placer mining, large buckets scoop up and separate the sediment
from placer deposits to search for minerals.Undersea Mining• Nodules are lumps of minerals on the deep ocean floor. However,
because of their location, these deposits are difficult to mine.
Resources and Energy Section 1
Comparing Metals, Nonmetals, and MetalloidsClick below to watch the Visual Concept.
