The Earth's Crust Flashcards
What does the Earth consist of?
A core, mantle, crust and is surrounded by the atmosphere
What is the Earth’s crust and upper part of the mantle cracked into?
A number of large pieces- tectonic plates
What are convection currents in the mantle driven by?
Natural radioactive processes
What do convection currents cause?
Plates to move a few cm each year
What can plate movements be?
Sudden and disastrous
Where do earthquakes and volcanoes occur?
At the boundaries between tectonic plates
What is the Earth’s crust, atmosphere and oceans the only source of that humans need?
Minerals and other resources
Why wasn’t Wegener’s theory accepted for many years?
Not enough evidence, couldn’t explain how continents moved
Describe Wegner’s idea of how continents formed
Continents were joined together, but they drifted apart
Why can’t scientists accurately predict when earthquakes and eruptions will occur?
Plates can quickly lerch forward, they can only say when it’s likely- not give exact dates, magma that rises can cool down- false alarm
