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Description
Flashcards by bilal mohamed, updated more than 1 year ago
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Created by bilal mohamed
over 7 years ago
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| Question | Answer |
| What is the Asthenosphere | A layer of plastic semi-solid rock in the lower mantle |
| Explain Continental drift | the sparating of the continents by drifting across the oceans |
| What is Magnetic stripping | patterns of magnetism trapped in rocks on each side of plate boundaries |
| Define the Ocean trench | a deep trench in the ocean floor that is much deeper than the rest of the ocean floor |
| What are Plate tectonics | the theory that the Earth's crust is cracked into many large pieces that move on the Asthenosphere |
| What is Rifting | the process of continents breaking up, subsiding and allowing in the sea |
| How does the sea floor spread | It spreads when new crust forms at the oceans ridges |
| What is subduction | It is where the crust is sinking down into the Earth |
| When was the Continental dift proposed and by whom | The theory was proposed between 1912 and 1915. It was discovered by Alfred Wegener, a German meteorologist and geophysicist |
| He theorised that all the landmass were together. But what did he call it | He named Pangaea |
| What were Wegener main observations | The first was that the continents seemed to fit like a jigsaw. The second was that fossils of the same species were on continents that were a long way apart. |
| Who proposed the seafloor spreading theory | His name was Harry Hess, he mad this discovery in 1962 |
| characteristics of asthenosphere | The lithosphere-asthenosphere boundary is conventionally taken at the 1300 °C isotherm, above which the mantle behaves in a rigid fashion and below which it behaves in a ductile fashion.n the old oceanic mantle the transition from the lithosphere to the asthenosphere, the so-called lithosphere-asthenosphere boundary (LAB) is shallow (about 60 km in some regions) with a sharp and large velocity drop (5-10%).[7] At the mid-ocean ridges the LAB rises to within a few kilometers of the ocean floor. |
| Explain how Wegener deduced what Pangaea looked like | Around the single protocontinent or Pangaea was a single ocean called Panthalassa (all the sea). More than 2,000,000 years ago, in the late Triassic Period, Pangaea broke apart. Although Pangaea is an hypothesis, the idea that all the continents once formed a single supercontinent makes sense when you look at the shapes of the continents and how well they essentially fit together. |
| What are the different types of crust | There are two types of crust, the oceanic crust which is found on the ocean floor and the continental crust is the crust forming the continents |
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