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ERTH1000
| Question | Answer |
|---|---|
| How old is the earth? | 4.55Ga - 4.56Ga |
| Continental crust consists of | Silica and aluminium (SIAL) |
| How thick is continental crust and what type of rocks are found? | 20-120km thick and granitic rocks |
| How old is continental crust? | 2.2Ga |
| Oceanic crust consists of | Silica and magnesium (SIMA) |
| How thick is oceanic crust and what type of rock is found? | 5-11km thick and balsatic rocks |
| How old is oceanic crust? | >200Ma |
| What is the MOHO discontinuity? | The boundary between the crust and mantle |
| Diamonds are the stable form of carbon where? | Lithosphere |
| State Wegener's theory of continental drift | continents had once formed a single landmass before breaking apart and drifting to their present locations |
| Wegener's theory of continental drift is based on | Palaeontological evidence, rock types and climatic indicators |
| How is the continental drift theory tested? | Palaeomagnetic data and age dating of ocean basalts |
| How do continents move? | The ocean floor spreads apart at the top of a mantle convection cell therefore sea spreading moves continents |
| Does the asthenosphere move? | No |
| How are new plates and oceans created? | Asthenosphere pushes up moving lithosphere away from each other |
| What is a convergent plate boundary? | When crust is being destroyed and recycled back into the interior of the earth as one plate dives under the other |
| What is oceanic-continental convergence? | When an oceanic plate pushes into and subducts under a continental plate. The continental crust is lifted upwards creating mountain ranges |
| What is oceanic-oceanic convergence? Give an example | When 2 oceanic plates converge and one is subducted under the other forming deep oceanic trenches eg Mariana's Trench |
| What is continental-continental convergence? Give an example | When 2 continents meet head on and the crust buckles and is pushed upwards eg Himalayas |
| What is a divergent plate boundary? Give an example | new crust being created as 2 or more plates pull away from each other eg Mid-Atlantic Ridge |
| What is a transform plate boundary? Give an example | 2 plates sliding horizontally past each other eg San Andreas Fault |
| If new crust is being formed how come the earth doesn't get any larger? | In subduction zones the crust gets recycled back into the mantle |
| What is a hotspot? | Regions where the mantle is very hot and where volcanic activity occurs with no association to plate boundaries |
| How can the motion of plates be described? | Pole of rotation and angular velocity |
| What are the 2 main forces involved with plate movement? | Ridge push and slab pull |
| What is ridge push? | Uplifted asthenosphere at ridges exerts a force on the overlying lithosphere |
| What is slab pull? | Sinking into mantle at subduction zone pulls the plate |
| The length of subduction zones of a plate is proportional to | the speed of plate motion |
| How fast is the Australian plate moving? | 7cm/yr NE subducting under the Indonesian plate |
| At what temp does basalt completely melt at? | 2000 degrees |
| How can mantle be melted? | Decompression- rise of warm mantle to lower pressure environment and Hydration- addition of water moves melting regime to lower temps |
| How long ago did Pangea occur? | 0.3Ga |
| How do mountains affect climate? | Windward side of mountains are fertile and rain clouds form because moist air is cooled by ascent. Lee side of mountains is dry because of moisture loss by rain. eg Ganges is fertile, Himalayas are arid |
| What is nonconformity? | Time breaks between igneous rock and overlying sediment |
| What is angular conformity? | time break with older strata dipping at an angle relative to the overlying younger strata |
| What is disconformity? | Time break with parallel strata above and below unconformable contact |
| What are isotopes? | of a particular element with the same number of protons in the nucleus but different numbers of neutrons |
| What is life made of? | Carbon, liquid water, energy |
| What are autotrophs? | Produces complex organic molecules from simple inorganic molecules using photosynthesis or chemosynthesis |
| What is the chemical equation for photosynthesis? | 6H2O + 6CO2 --> C6H12O6 + 6O2 |
| Photosynthesis... | Stores energy as sugar, uses CO2 and H2O, produces oxygen |
| Respiration... | releases energy from sugar, releases CO2 and H2O, consumes oxygen |
| What are stromatolites? | layered structures built of ancient microbial mats |
| When did eukaryotes start to appear? | 1.4Ga |
Created by:
cmw001001
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