What are the earth's layers divided into and how dow they move?
Tectonic Plates move by convection current
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How can the previous position of continents be calculated by scientists?
Sediments in rocks contain magnetite. This has magnetic properties so it is magnetized in one line when formed according to the magnetic field at its location
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what can be worked out by measuring the magnetization of rocks on continents ?
the angle of magnetization of the magnetite crystals is used to work out the latitude the rocks were formed. This is because at the equator the lines of the magnetic field are horizontal but at the poles the are at an angle to horizontal
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What other evidence was combined with the magnetic field evidence to help support the theory of continental drift and plate tectonics ?
That different types of rocks were created when the continents moved around due to different climates in different places of the world
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how can we work out the history of a sedimentary rock such as sandstone?
By looking at the shape and size of the sand grains in the rock. Geologists can find out about the conditions the rock was formed. I.E river or desert etc
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Why did a chlorine based chemical industry grow up by the river Mersey in England ?
Because underground salt deposits, coal mines, and limestone quarries were nearby and these can be used to make chlorine
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How was sandstone in the peak district formed ?
About 310 million years ago when mountains there were eroded by fast-flowing rivers carrying sediment. This was deposited into layers and then compacted to form coarse sandstone
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How did salt deposits in Cheshire form ?
About 220 million years ago, seawater moved inland and created an chain of shallow salt marshes. Deposits of rock salt formed as the water in the marshes evaporated.
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How did coal shale form containing fossil fern ?
280 million years ago, river deltas in the area got bigger and created swamp land. Tree ferns grew and when the died they were covered by sediment, compressed, heated and turned to coal
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How was limestone formed in the Peak District containing fossils of crinoid sea lilies ?
350 million years ago the Peak District lay below a warm, shallow sea south of the equator. When plants and animals died they sank to the bottom and formed fossils in the thickening mass of pure limestone.
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What is the importance of salt ?
it was used to preserve meat and fish and now is used in the food industry to process, preserve food and add flavor. It is also used to treat icy roads in winter.
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How is salt extracted from the sea ?
In hot countries sea water is run into pans and allowed to evaporate in the sun. This leaves behind mainly sodium chloride
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Rock salt and where it comes from
underground salt mines and is mainly used to spread on roads. The salt is in the form of the mineral halite which is not pure. This is why it can be used on roads
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Other cards in this set
Card 2
Front
How can the previous position of continents be calculated by scientists?
Back
Sediments in rocks contain magnetite. This has magnetic properties so it is magnetized in one line when formed according to the magnetic field at its location
Card 3
Front
what can be worked out by measuring the magnetization of rocks on continents ?
Back
Card 4
Front
What other evidence was combined with the magnetic field evidence to help support the theory of continental drift and plate tectonics ?
Back
Card 5
Front
how can we work out the history of a sedimentary rock such as sandstone?
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