7h Materials From The Earth Flashcards
How are sedimentary rocks made
When rocks are eroded ( can be chemical, biological or physical ) they can be transported by moving water , wind or ice . These fragments are deposited as sediment when the wind or water slows down or the ice melts . Over a lond time more layers of sediment are deposited squashing the bottom layers . This pressure forces the grains of sediment closer which squeeze the water out . This is called compaction. Crystals are formed which acts as a glue that cements the grains together . This is called cementation . Together compaction and cementation change the grains of sediment 8nto rocks
Fossils form when
A dead plant or animal becomes covered in sediment
What is limestone made of
Calcium carbonate main,y
Where the river is flowing faster there will be
Where the river is flowing faster there will be less deposited grains
Where the river is flowing slower there will be
Larger deposited grains
What are fossil fuels
Coal oil and natural gas . Because they are formed from remains of animals and plants
How is crude oil and natural gas made
Millions of years ago many organisms died in the sea , their bodies sinked down to the bottom of the sea bed . Th pressure do their bodies and sediment caused a reaction changing them into oil and natural gas
How was coal formed
Many remains of plants and animals fell into swamps where they were buried by sediment but they did not rot and eventually transformed into coal .
Fossil fuels are not renewable because
They will eventually run out and their formation process takes millions of years
