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Coal
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Coal
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Coal is called a fossil fuel, because it is formed from fossilised dead plants. To most geologists, coal is a type of sedimentary rock made of solid minerals. These originally come from plants such as ferns in swamps that died long ago. The plants lay under water for millions of years and then were rapidly buried by other sediments (up to 8Km thick in Collie WA). Basically sandstone, time and pressure made them into coal. Fossil leaves and plant spores have been found in coal bearing strata. The name of one plant is Glossopteris which is now an extinct plant. (Unfortunately due to copyright laws we can not put up a picture here of this plant). Most of our coal here in Collie, Western Australia, was formed in the Permian period-280 million years ago. At this time Australia was apart of large continent of Gondwana and close to the South Pole. Glaciers covered Western Australia. 20 million years later Gondwana had drifted north and it had warmed up where swamps and forests developed in large parts of the South West of Western Australia. Coal is found in layers known as seams which can be up to several meters thick. Between the seams there are layers of sandstone or mudstone. Below the coal seams are rocks that contain pebbles and cobbles of dolerite, quartzite, and granite.
Photographed at the Rockingham Environment Centre The coal used from Collie produces 80% of Western Australia's power. Burning coal in power stations is one of the ways in which electricity is generated by producing heat. Firstly the plants took in the energy from the sun and preserved it even after the plant died but did not completely rot away. When the coal is burned it releases large amounts of energy as heat. A steam train uses that heat to produce steam to turn the wheels. A power station uses the steam produced by the heat of burning coal to turn turbines, that run huge generators, that produce electricity. There are different grades of coal. Peat is a very young form of coal and is still forming today.
Peat. Photographed at the Geological Museum The combined mines in Collie contain 2400 million tones of coal. Imagine how fast a steam train would go with all that coal in it!
The reason why Collie has not eroded away like most other rocks of the Permian period is because Collie is in a basin which is sunken down.
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