Iron is a ubiquitous element found in nature. It is essential for various industrial and biological applications, including steel production, medicine, and the human body’s hemoglobin. It is the fourth most abundant element in the Earth’s crust, but where is iron found in nature? Let’s explore its natural occurrences.
Iron Ore Deposits
Iron ore deposits are the most common sources of iron in nature. They are rocks and minerals from which metallic iron can be extracted. There are four main types of iron ore deposits:
- Magnetite: Magnetite is one of the most valuable iron ores due to its high iron content (72 percent). It is black or brownish-black, with a metallic luster and a fine-grained texture. It is found in igneous and metamorphic rocks and in hydrothermal veins.
- Hematite: Hematite is one of the most abundant iron ores. It is formed by the oxidation of iron minerals in rocks. It is red or reddish-brown, with a earthy, metallic luster. It is found in sedimentary rocks and in hydrothermal veins.
- Goethite: Goethite is a hydrated iron oxide that is formed by the weathering of iron-bearing minerals. It is yellowish-brown or reddish-brown, with an earthy, metallic luster. It is found in soil and in sedimentary rocks.
- Siderite: Siderite is a carbonate mineral that contains iron. It is yellowish-brown or brownish-black, with a dull luster. It is found in sedimentary rocks and in hydrothermal veins.
Iron in Rocks and Minerals
Iron is also found in rocks and minerals other than iron ore deposits. These include:
Mafic and Ultramafic Rocks
Mafic and ultramafic rocks are igneous rocks that contain high concentrations of iron and magnesium. They are typically dark-colored and heavy. Examples include basalt, gabbro, and peridotite.
Banded Iron Formations
Banded iron formations (BIFs) are sedimentary rocks that contain alternating layers of iron-rich minerals and silica-rich minerals. They are important sources of iron ore. BIFs were formed between 3.7 and 1.8 billion years ago, during the Archean and Proterozoic eons.
Igneous Rocks
Igneous rocks, such as granite, contain small amounts of iron. Most of the iron in these rocks is in the form of magnetite or ilmenite.
Iron in Water
Iron is also found in water, but in very small amounts. It can be in the form of dissolved ions or solid particles. Iron that is dissolved in water is not visible with the naked eye, but can cause discoloration of water or stains on surfaces. Iron can be removed from water through treatment processes such as filtration, oxidation, and sedimentation.
Iron in the Human Body
The human body contains about 4 grams of iron, most of which is in the form of hemoglobin in red blood cells. Hemoglobin is the protein that carries oxygen throughout the body. Iron is also found in myoglobin, which is the protein that stores oxygen in muscles. Iron is essential for the proper functioning of cells and the immune system. Iron deficiency can lead to anemia, fatigue, and weakness.
The Geographical Distribution of Iron
Iron is found all over the world, but the largest deposits are located in Australia, Brazil, China, India, Russia, and the United States. Other major producers of iron ore include Canada, Iran, Mexico, and Ukraine. Iron is also found in smaller quantities in many other countries.
In Conclusion
Iron is a vital element with a diverse range of applications. It is found in abundance all over the world, primarily in the form of iron ore deposits. It is also present in rocks and minerals, water, and the human body. Understanding where iron is found in nature is essential for its effective exploitation and use.
References
1. Condie, K. C. (2016). Earth as an Evolving Planetary System. Academic Press.
2. Hurlbut Jr, C. S., & Klein, C. (1985). Manual of mineralogy (movable rock). John Wiley & Sons.
3. Klein, C., & Dutrow, B. (2016). Manual of mineral science. John Wiley & Sons.
4. Lide, D. R. (Ed.). (2005). CRC handbook of chemistry and physics (86th ed.). CRC Press.
5. ScienceDirect. (n.d.). Iron. Retrieved June 4, 2021, from https://www.sciencedirect.com/topics/earth-and-planetary-sciences/iron
Most Common Questions and Answers
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What is iron ore?
Iron ore is a type of rock that contains metallic iron in high enough concentrations to be extracted commercially.
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What are the different types of iron ore deposits?
The four main types of iron ore deposits are magnetite, hematite, goethite, and siderite.
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What are mafic and ultramafic rocks?
Mafic and ultramafic rocks are igneous rocks that contain high concentrations of iron and magnesium.
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What are banded iron formations?
Banded iron formations (BIFs) are sedimentary rocks that contain alternating layers of iron-rich minerals and silica-rich minerals.
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What is hemoglobin?
Hemoglobin is the protein that carries oxygen throughout the body. It contains iron.
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What is myoglobin?
Myoglobin is the protein that stores oxygen in muscles. It contains iron.