Earth and atmosphere: rock cycles Flashcards
Describe how igneous rock is formed.
Igneous rock is formed when magma solidifies.
What is extrusive rock?
Extrusive rock is a type of igneous rock which solidifies inside a volcano and has larger crystals.
What is intrusive rock?
Intrusive rock is a type of igneous rock which solidifies outside the volcano and has smaller crystals.
What is sedimentation?
Sedimentation is when remains of other broken rocks deposit and build up in layer, called sediments. This is the first main step of the sedimentary rock cycle.
What is compaction?
Compaction is when the sediments weigh onto of each other and squash the other layers at the bottom This is the second step of the sedimentary rock cycle.
What is cementation?
Cementation is the process when the water is squeezed out from between the sediments and crystals of different salts form. the crystals stick the pieces of rock together. This is the final step of the sedimentary rock cycle.
Describe how sedimentary rock is formed.
Sedimentary rocks are formed from broken remains of other rocks which have joined together. There are 3 main stages of the process: sedimentation, compaction and cementation.
What is physical weathering?
Physical weathering is also known as freeze-thaw weathering.
- water finds it’s way into small cracks in the rock.
- at night the the water then freeze and this makes the cracks get even bigger in the rock.
- during the day the frozen water thaws and at night the water freezes again. This process happens over and over again causing more and more cracks to appear in the rock.
- finally the fragment of rock breaks off due to the many many cracks.
What is chemical weathering?
Rain water is slightly acidic, in urban the level of acid in the rain is higher due to the toxic fumes from factories. The acid in the rain cause rocks to break away bit by bit and this is the process of chemical weathering.
What is erosion?
Erosion is the movement of rocks. It can happen by people, animals, water or wind
