Explore the field of geology that provides us with the raw earth materials we need.
In this lesson, we’ll learn the scope of economic geology and introduce some topics that will be covered in greater detail in the rest of the chapter.
Intro to Economic Geology
You probably don’t think about it much in your daily life, but the majority of the modern conveniences you enjoy are reliant on Earth’s natural resources. A perfect example is the computer you are using to watch this video.
Inside your computer, you’d find a microprocessor made of silicon, drives made of various metals and metal alloys, all of which are likely encased in plastic, which is made from oil, or maybe your computer has an aluminum case, which is also from the earth. Before they powered your computer, the components of these parts once started as raw materials within the earth.The earth’s population is currently over seven billion people and growing. More people means that we need more natural resources. As the population grows, we are facing many important questions. How long will our oil reserves last? Are there new ore bodies that we haven’t discovered yet? Can we find new mineral resources deeper in the earth?To help us answer these questions, we turn to the field of economic geology.
Economic geology is the study of the formation and extraction of earth materials that have some economic potential in society. Economic potential means that they are materials that are currently valuable or may potentially be valuable in the future. These economically valuable materials are generally called mineral resources and include minerals and ore deposits.
Ore deposits are just useful rocks that are mined for a profit, such as gold and copper. Oil and gas are also commonly referred to as mineral resources, despite the fact that they are not actually minerals.
Renewable vs. Nonrenewable Resources
What makes mineral resources unique and valuable is that they are only rarely renewable in our lifespans.
Renewable resources are earth resources that are naturally replenished on short time scales, like solar energy. Nonrenewable resources are those that exist in finite amounts. These also include resources that we use at exponentially higher rates than are being naturally replenished.You’ve likely heard crude oil referred to as a nonrenewable resource. Oil is formed from decomposing organic material that is compressed and eventually broken down into carbon and hydrogen molecules. While this process can still occur today, scientists think that it takes hundreds of thousands of years to make a swamp into a barrel of crude oil.
Thus, we consider oil to be nonrenewable because the supply will not be naturally replenished in our lifetimes.
Understanding Mineral Resources
The value of mineral resources is dependent on several factors. First, there must be a market demand for a particular resource.
It’s not valuable unless we have some use for it. Once a resource is determined to be useful, the particular qualities of the resource determine its value, including whether it’s renewable, its rarity, and the ease at which geologists can locate and extract it.Mineral resources have formed very slowly by major earth processes throughout the history of Earth. Some of these processes are extremely common, and thus, the resulting mineral resources are found globally. For instance, limestone is a common building material. Limestone is a rock formed in shallow warm seas by the deposition of tiny carbonate shells.
Not only is it a common rock in the geologic record, there are numerous warm shallow seas globally where limestone is slowly being formed today. On the other hand, resources like diamonds are extremely rare. They are formed in deposits called kimberlites, which are vertical intrusions of magma from deep within the earth’s crust. Only about 50 mines globally produce the majority of the world’s diamonds.
Once geologists locate valuable mineral resources, the process is not over. Economic geologists must then evaluate whether the concentration of the resource in the deposit is worth the cost of extracting it. Thus, geologists estimate the grade, which is the relative quantity of ore in an ore body. For instance, the best gold mines in the world have a grade of around ten grams per ton. This means that every ton of rock mined from the ground contains only ten grams of gold.
That’s less than half an ounce of gold in a ton of rock! Gold is so valuable that it is still profitable to mine despite these seemingly low returns.Given the scarcity of mineral resources, accurately locating them and assessing their worth is extremely important. To find these important resources, we must understand more about the processes that form them. The lessons in this chapter will delve into how economically valuable minerals become concentrated, what makes them unique compared to other minerals, and where we can expect to find them on Earth.
So in summary, economic geology is the study of the formation and extraction of earth materials that have some economic potential in society, meaning they are already valuable or they have the potential to become valuable. These resources are called mineral resources and include minerals, ores, oil, and gas. Mineral resources are valuable because they are often nonrenewable resources.
They are also more valuable when they are more unique or rare deposits. The other lessons in this chapter will investigate further on how some of these resources were formed and how economic geologists know where to find them.
As you complete the lesson, your goal should be to:
- Define economic geology and economic potential
- Name two types of economically valuable materials
- Differentiate between renewable and nonrenewable resources
- Recognize the factors that impact the value of mineral resources
- Explain how economic geologists determine the worth, or grade, of mineral resources