2598446
Description
Flashcards by 8bousteadj, updated more than 1 year ago
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Created by 8bousteadj
almost 9 years ago
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| Question | Answer |
| Who came up with plate tectonics theory? | Alfred Wegener (1912) |
| What is the 'inner core'? | A solid ball of iron and nickel |
| What is the 'outer core'? | It surrounds the inner core and is semi-molten and contains lots of iron and nickel |
| Name two layers of the mantle and their properties | The lithosphere (rigid mantle and the crust) The asthenosphere (semi-molten mantle) |
| Name two types of crust and their thickness | Continental crust is older and thicker (30 - 70km thick) and is less dense Oceanic crust is newer and thinner (6-10km thick) and is more dense |
| What causes the earth's plates to move and how? | Convection currents Radioactive decay of some elements in the mantle produce heat... This heat makes lower parts of the asthenosphere less dense and it rises As they move towards the top of the mantle they cool down, become more dense once again and slowly sink This creates a circular motion of semi-molten rock, known as convection currents Convection currents in the asthenosphere create drag on the solid base of the tectonic plates, which causes them to move |
| How is new crust formed? | When rising convection currents diverge from each other, they also cause the plates to diverge. This creates a gap in between the two plates. Magma rises to then fill this gap and cools, forming new crust. |
| Who came up with sea floor spreading? | Harry Hess |
| What does sea floor spreading have to do with plate tectonics? | It explains how the plates move apart from each other |
| Name 4 types of evidence for plate tectonics theory | Geology Fossil records Living species Climatology |
| What type of study is evidence that supports sea floor spreading? | Palaeomagnetism |
| What is palaeomagnetism | The study of the Earth's magnetic field |
| How does palaeomagnetism support sea floor spreading? | Every 200,000 years the Earth's magnetic field reverses polarity Magma that erupts from mid-ocean ridges brings up magnetic minerals that align themselves with the earth's magnetic field once the magma has solidified Observing the rock from the MARs, the magnetic mineral's polarity switch in alternating stripe patterns This also helps indicate the age of the crust |
| What was Alfred Wegener's supercontinent called? | Pangea |
| How does geology support continental drift and give examples | Rocks of the same age and composition match up in some countries (South America and Africa) Mountain ranges across countries also match up (Finland, Sweden, Norway, Scotland and North America match up) |
| How do fossil records support plate tectonics theory? | By fitting the land masses together, distribution of the fossils match up. The Mesosaurus for example is found in many continents, and by studying it's fossils it could not have migrated across oceans to other continents that are the size of ours today |
| How do living species support plate tectonics theory and give an example | The same living organisms can be found on different continents. A specific family of earthworms are found in New Zealand, Asia and North America and couldn't have traveled across the sea |
| How does climatology support plate tectonics theory and give examples | Continents that were thought to once have been joined should have had similar climates. Similar glacial deposits have been found in India, Africa, Antarctica and Australia |
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