After the oceans formed; you could imagine that the water was full of all sorts of materials, which were dissolved from the rocks as the waters slowly filled up the oceans, when the earth cooled sufficiently for large volumes of water to accumulate.
The dissolved materials included a lot of iron salts (probably iron chloride and iron sulphate); as well as the soduim chloride still present today.
The first forms of life that developed are thought to be bacteria (similar to today's blue-green algae). They didn't require oxygen, but converted carbon dioxide and water to sugars using sunlight; much like todays plants. Oxygen was actually a waste product, so they excreted it (blue green algae still do this today). Conditions were ideal for them, so they multiplied rapidly, and had the oceans mostly to themselves for hundreds of millions of years.
The oxygen they gave off reacted with the dissolved iron salts in the water to form iron hydroxides and iron oxides. These materials are insoluble; so they settled to the bottom. It took millions of years for the oxygen to react with all the dissolved iron, and very thick deposits formed. These can still be seen today, and are called
'banded iron formation'.
Finally, when most of the iron had been precipitated out of the water, there was an excess of oxygen, which was partly dissolved in the water, and then also passed into the atmosphere, enabling marine and terrestrial oxygen requiring life forms to develop. This where the oxygen in the atmosphere came from; and if it weren't for the early cyanobacteria, life on earth would not exist.
Over time, the large deposits of iron rich sediments were moved and changed because of the movements of the crustal plates, and they eventually formed large deposits of magnetite and haematite, which make up most of the world's iron ore deposits.
That is why most iron ore deposits are found in ancient rock formations.
Name the 3 ways ores are formed?
Ore is a rock that contains minerals , an example of an ore can be almost anything!
No, Bauxite is not a type of iron ore. it is an ore of aluminum.
Its considered an ore when it contains enough of a useful substance that it can be sold for a profit.
Ore is a general description of the range of economic minerals which might be present within a rock. For example the Zn-Pb mines of Ireland extract ore rocks which are rich in the minerals sphalerite and Galena. All of these 'minerals' are 'ore'.
An ore vein is a crack or crevice in a rock where minerals can be found.
veins
No. By definition a rock is made of minerals. An ore is a mineral resource that can be extracted, refined, and sold at a profit.
Minerals are minerals. An ore is a rock matrix that has a rather large amount of a certain mineral in it, hence "Iron ore", Silver ore", etc.
A mixture of minerals is called an ore
A mixture of minerals is called an ore
Ore is a rock that contains minerals , an example of an ore can be almost anything!
Ore is made up of minerals.
Ore.
Minerals...
ore
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Ore