Iron Ore Deposits




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Image from: Kentucky Coal Education Web Site
Eventually, as with the development of photosynthesis along sulfur and methane pathways, where sulfur and methane products are produced, photosynthesis along the oxygen pathway, where oxygen is produced, came into being.

One important thing to know about oxygen is that it is very reactive. It is one of the most reactive of all the elements in nature. This means that it will readily attack and attach itself to other elements. In particular, iron, sulfur, and manganese are readily attacked by oxygen.

As molecular oxygen began to be produced by early autotrophs, a curious phenomena occured. Large amounts of iron which had accumulated in the early ocean as both FeSO4- and a solid FeS2 (pyrite) from naturally occuring weathering and as a product of heterotrophic activity, were attacked by the accumulating O2. As O2 reacts with FeS2 (pyrite), Fe2O3 (limonite) is produced. When O2 reacts with FeSO4-, Fe2O3 (hematite) is produced. These rocks, along with magnetite (Fe3O4 - a magnetic rock) and siderite (FeCO3), are also called iron ores. Oxide rocks such as these are mined today, and the iron (Fe) they contain is extracted.

Over a period of a billion years, huge deposits of iron ores were laid at the bottom of the sea. This activity took place between 3.5 and 2.5 billion years ago. Iron ores mined today in the United States, Australia, and South Africa, are part of the huge deposits laid down at that time. Once the oceans were swept clean of iron, then the oxygen could begin to accumulate in the atmosphere, and respiration by sophisticated life forms could begin in earnest. It took a billion years for this process to complete. When it was finished, it closed the period in the history of the Earth which we call the Archean .


Iron Ore Deposits




Click on image for full size version (43K JPG)
Image from: Kentucky Coal Education Web Site
Eventually, photosynthesis by the earliest forms of plant life (a form of life capable of feeding itself instead of feeding off of others) began to produce significant amounts of oxygen. One important thing to know about oxygen is that it likes to react with things. It is one of the most reactive of all the elements in nature. This means that it will readily attack and attach itself to other elements. Iron, in particular, is readily attacked by oxygen.

Other forms of heterotrophic early life (life forms which eat things outside themselves) had been producing waste products such as iron in the form of pyrite (a rock which is sometimes called "fools gold" because it resembles gold) which built up in the early ocean. As oxygen began to be produced, a curious phenomena occured. Large amounts of iron which had accumulated in the early ocean were attacked by the accumulating oxygen. When oxygen (O2) reacts with iron (Fe) containing substances such as FeS2 (pyrite), iron ores are produced. Oxide rocks such as limonite, hematite, magnetite (a magnetic rock), and siderite are among the iron ores. Rocks such as these are mined today, and the iron (Fe) they contain is extracted.

Over a period of a billion years, huge deposits of iron ores were laid at the bottom of the sea. This activity took place between 3.5 and 2.5 billion years ago. Iron ores mined today in the United States, Australia, and South Africa, are part of the huge deposits laid down at that time. Once the oceans were swept clean of iron, then the oxygen could begin to accumulate in the atmosphere, and respiration by sophisticated life forms could begin in earnest. It took a billion years for this process to complete. When it was finished, it closed the period in the history of the Earth which we call the Archean.


Iron Ore Deposits




Click on image for full size version (43K JPG)
Image from: Kentucky Coal Education Web Site
Eventually, photosynthesis by the earliest forms of plant life (a form of life capable of feeding itself instead of feeding off of others) began to produce significant amounts of oxygen. One important thing to know about oxygen is that it likes to attack other elements and attach itself to them. Iron, in particular, is easily attacked by oxygen.

Other forms of heterotrophic early life (life forms which eat things outside themselves) had been producing waste products such as iron, which built up in the early ocean. As oxygen began to be produced, a peculiar thing happened. Large amounts of iron which had accumulated in the early ocean were attacked by the accumulating oxygen. When oxygen reacts with iron, iron ores are produced. Today, iron ores are taken out of the ground by miners, and the iron they contain is used by human beings to make lots of things.

For a billion years, the oxygen produced by early plant life attacked leftover iron in the ocean, and huge deposits of iron ores were laid down at the bottom of the sea. This activity took place between 3.5 and 2.5 billion years ago. Iron ores mined today in the United States, Australia, and South Africa, are part of the huge deposits laid down at that time. Once the oceans were swept clean of iron, then the oxygen could begin to build up in the atmosphere, and respiration by sophisticated life forms could begin in earnest. It took a billion years for this process to complete. When it was finished, it closed the period in the history of the Earth which we call the Archean .




Last modified January 17, 1999 by the Windows Team

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