Minerals in Britain Flashcards
These are done
What are tectonic plates?
The outer layers of the Earth (the crust and upper part of the mantle) are divided into massive portions of rock called tectonic plates. These plates fit together like a jigsaw puzzle
What is the name of the currents that give these plates the ability to move ?
Convection currents
How do Geologists document the movement of continents.
They use magnetic clues in rocks. This movement is tracked by studying magnetic particles contained in some rocks such as certain types of lava and sediment that contain magnetite.
When lava has cooled, magnetite can become magnetised in the direction of the Earth’s magnetic field at that particular time. A similar process occurs with sediment
What do fossils of plants and animals found in the rock distinctive of certain geological time periods. tell us about the environment in which they existed
grains of sand found in rock can be compared against grains found in deserts or rivers to determine if they were air blown or water borne
ripples in rocks formed by wind blowing or water flowing
How is coal formed?
When plants have died and formed peat due to a lack of oxygen, the peat has been buried by sediment leading to compression and heating. This eventually formed coal.
Mining - Large earth moving equipment is used to extract what sort of salt? .
rock salt
How was rock salt formed? .
Seawater that was inland millions of years ago created salt marshes. As water in these marshes evaporated, deposits of rock salt formed
What natural processes led to other valuable resources than coal being formed?
Other processes such as erosion and sedimentation have led to the formation of other valuable resources such as sandstone.
What is commonly referred to as salt is the compound what ?
What is commonly referred to as salt is the compound sodium chloride.
what does the food industry use salt for?
It has long been important in the food industry as a preservative and also to add flavour.
What is Another common use of salt
to treat icy roads in winter as salty water has a lower freezing point then pure water
Salt can be obtained by…?
Salt can be obtained from the sea or from underground salt deposits.
when pure salt is needed for industrial purposes, a different method is used than mining. What is it?
Water is forced down a borehole into rock. The salt dissolves making a solution of brine and this solution is withdrawn to the surface and pumped to a purification plant. Water is evaporated from the brine under a range of pressures making the process more efficient. The salt crystallises and is separated from any remaining brine by filtering or using a centrifuge.
What is subsidence? How can it be avoided?
Extracting salt in solution can create large underground caverns. This can lead to bedrock collapsing and as a consequence, cause the lowering of the Earth’s surface. This is known as subsidence. It can be avoided by sensibly spacing out the holes created so the surface is supported by a sufficient amount of rock underground.
