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Definition
1941, wegener
proposed continents once formed Pangea surrounded by Panthalassa ocean, evidence by fossil distribution, rock types, glaciation patterns, paleoclimatology |
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Term
| rejection of continental drift |
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Definition
| no mechanism, little understading of ocean floor until WW2 |
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Definition
1960s
came after extensive study of sea floor; spreading of the sea floor offered proof and suggested a mechanism
earths surface full of platers composed of continental and oceanic crusts
convergent, divergent, transform boundaries |
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Term
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Definition
igneous rocks with high Fe content weakly magnetized by Earth's magnetic field as crystallize; leads to suggestion of polar wandering - BUT polar wandering curves diferent for different continents
poles didnt move, continents did
poles reverse many times |
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Definition
| all has formed since the Jurassic period |
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Term
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Definition
| plates (lithosphere) composed of crust and upper mantle - move on weak parts of mantle (asthenosphere) |
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Definition
| 35+ km thick, density 2.7 g/cm3, intermediate/felsic composition |
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Definition
| 5-12 km thick, 3.0 g/cm3; mafic composition; basalt/gabro |
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Term
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Definition
| mid ocean ridges, typically normal faults |
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Term
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Definition
| subduction at deep sea trenches, island arcs at o-c, mountain range and volcanic arc at o-c |
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| theories of why plates move |
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Definition
heat escaping the core
plate pull - cold plates subduct bc they are denser then plates below heated by mantle; plate push - o plates slip off mid ocean ridge and becomes more dense |
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Term
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Definition
hot spots in asthenosphere, long lived
caused by upwelling of mantle which has possibly been displaced by subducting plates, may initiate continental break up or mass extinction events |
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Term
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Definition
| From origin of earth (4.6 billion) to formation of oldest known rock (4.04 billion) |
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Definition
| 87% of Earth's historyl originally ignored because lack of fossils for correlation, now correlated by radiometric dating |
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| Big Bang - 15-18 billion years ago, origin of the universe; all matter compressed into one mass, 100 billion degrees C, still moving outward extremely fast |
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| 1 billions years after Big Bang; matter concentrates due to gravity; lens shaped with arms of high density; stars form aloner leading edges |
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Term
| formation of solar system |
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Definition
| solar nebula - rotating cloud of gas and dust; accretion - particles attract, form protoplanets; High T & P at center creates sun |
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Definition
| most abundant meteorite; ultratamafic, 4.6 billion years old; carbonaceous ones include amino acids and are extremely rare |
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| 2 Fe-Ni allows in large interlocking crystals; shows slow cooling in large extraterrestrial body; formed in asteroid that later broke? |
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Term
| terrestrial vs. outer planets |
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Definition
radiation from sun blew away light element from inner planets
terrestrial - Mercury, Venus, Earth, Mars, higher density
outer- Jupiter, Saturn, Uranus, Neptune |
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