3.2.1 Ore Deposits

Ore Deposits

3.2.1

Objectives

Learners can:

• explain what an ore deposit is and why they are important

• describe the exploration process for finding ores

• identify the factors that determine the location and size of ore deposits

• geology

• mineral

• natural resource

Prerequisite Vocab

• crystal

• crystallization

• ore

• ore deposit

• vein

New Vocab

Vocabulary

a rock with a natural geometric pattern

Crystal

the process by which a substance's molecules or atoms align in a repeating structure

Crystallization

valuable material found within rock

Ore

​a concentration of minerals that can be used profitably

Ore Deposit

a fracture in a rock containing a deposit of minerals or ore

Vein

Match

Match the vocabulary word with its definition.

• mineral

• geology

• natural resource

a natural, solid substance found in rock

study of rocks and Earth

anything usable in nature

• a natural, solid substance found in rock

• study of rocks and Earth

• anything usable in nature

Materials

Cracking Open Geodes

• dish towel

• geodes

• rock pick

• safety goggles

San Francisco 49ers

You may be surprised to learn that the name of this football team is a reference to California miners who panned for gold. In 1848, the California gold rush began with many individuals moving to the region to try and make their fortune. During this time, settlements such as San Francisco experienced significant growth.

The name “49ers” refers to the people who flocked to California in 1849 during the peak of the California gold rush in search of gold deposits. The gold rush brought many people to California in the mid-19th century.

​go birds

Ore is a valuable material found within rock. The reason ore is valuable is that it contains useful minerals. Minerals are used for many regularly used products. It may be hard to see the value in a seemingly ordinary-looking rock seen here. However, this rock is actually bauxite ore. Bauxite is an important source of aluminum. Aluminum is used in materials such as electrical conductors, food-processing equipment, refrigerators, and aircraft.

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Ore

Mineral Formation

• minerals form when magma/lava cools

• as minerals cool, they crystallize

• granite is a mineral made from cooled magma

Magma & Lava

• most water contains elements

• elements+water=solution

• when water evaporates, minerals are left behind

​​Solutions

• hot groundwater carries dissolved minerals

• the groundwater moves through cracks and deposits the minerals

• veins are formed

Hot Groundwater

Geodes form when water gets into cracks or pores within a rock and crystals form inside the empty spaces. This allows large crystals to grow. A crystal is a rock with a natural geometric pattern.

Finding geodes is exciting because they can take millions of years to form. A rock collector might suspect a rock contains crystals inside if it is spherical in shape and has a bumpy, uneven surface. It might sound hollow when tapped or even rattle inside. But the only way to be certain is to use a rock hammer to break it open to see if the rock contains crystals inside.

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Geodes

Geode Activity

Put the geode on a hard concrete surface, like a sidewalk, patio, or garage floor. Then cover it with a cloth to help prevent rock fragments from hurting you.

Prep

Wearing your safety goggles, use the rock pick to gently strike the geode along the middle until it splits open. If you hit too hard, you may cause the geode to break into small pieces.

Break

Examine the interior of the geode. In most cases, crystals should be visible. Repeat the activity steps with a new geode if your geode does not contain crystals.

Examine

Open Ended

Share what you observed about the geode you broke open.

Ore Deposits

Recall that rocks that contain minerals are called ore. However, the value of the minerals that are contained in the ore will vary. Certain places on Earth are more likely to have certain ores than other locations. Ore deposits are a concentration of minerals that can be used profitably. So, while mineral resources may be found in many areas around the world, there may only be a few locations with ore deposits worth extracting on a large scale.

The reason ore deposits are found spread around the world is because of the processes that form minerals. For example, copper is often found where groundwater has been heated by magma. This hot liquid leads to copper veins forming in the ground. However, there are only certain areas where these conditions occur to form large deposits of copper.

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Ore Deposits Cont.

1. Chile, in South America, is the top producer of copper.

2. ​The United States, Peru, China, and Australia are also big producers of copper.

3. Smaller copper deposits are also found in parts of Kazakhstan, Mexico, Argentina, Uruguay, Zambia, South Africa, Iran, and Papua New Guinea.

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Copper Deposits

Multiple Choice

Which of the following statements best explains the distribution of copper ore deposits around the world?

• There are several large copper ore deposits spread around the world.

• Every country has at least one large copper ore deposit.

• 
  Only a few countries have significant copper ore deposits.

• Copper ore deposits are evenly spread across Earth.

Locating Ore Deposits

Geology is the study of Earth's physical structure, its history, and the processes that shape it. Geologists are scientists who study the Earth and its processes, using a variety of tools and techniques to explore its composition, structure, and history. They will often look for indicators of certain geologic processes such as volcanic activity or rock types to determine the primary processes occurring in that area. With this information, geologists determine the most likely locations for ore deposits to occur.

Argentite is an important source of silver. It is found in mineral veins formed from heated groundwater. The heat is often associated with areas that are more volcanically active.

Argentite

Bauxite is a source of aluminum. It forms in tropical areas due to erosion related to certain types of clay soils.

Bauxite

Gold is found as veins running through rocks. Geologists find that the presence of other certain minerals provides clues to where gold may be located.

Gold

If a mineral deposit is not profitable, it is not considered an ore deposit. However, notable mineral locations are often mapped in case conditions change. New technology may make a mineral deposit profitable where it would not have been before.