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11 Cards in this Set
- Front
- Back
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What are the three types of plate boundaries?
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Divergent
Convergent Transform |
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What is accretion?
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A process by which material is added to a tectonic plate or a land mass
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What is the Wilson Cycle?
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The cyclical opening and closing of ocean basins caused by movement of the earth's plates
Named after John Tuzo Wilson |
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What are terranes?
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A fragment of crustal material formed on one tectonic plate and sutured to the crust lying on another plate
The crustal block preserves its own distinctive geologic history |
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What are two craters found in Manitoba?
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West Hawk Lake
St. Martin Crater |
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What is the K-T boundary?
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Boundary marking the end of the Cretaceous and beginning of Tertiary
result of a 10-km wide meteorite in the Yucatan Caused almost immediate species turnover at this boundary Formed an iridium-rich band of deposits around the world (iridium anomalies) |
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What is an iridium anomaly?
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an unusual abundance of iridium in a layer of rock strata, evidence of an extraterrestrial impact event (K-T boundary)
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What is shocked quartz?
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form of quartz that has a microscopic structure different from normal quartz - under intense pressure the crystalline structure of quartz will be deformed along planes inside the crystal
Found in the K-T boundary - evidence of large impact |
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What are tectites?
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natural glass rocks up formed by the impact of large meteorites on earth's surface
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What were some of the consequences of a large scale impact that could have caused widespread death?
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Darkness and cold (ejecta in suspension for 2-3 months)
incineration - heating atmosphere by re-entering ballistic ejecta - ignited forests globally acid rain - oxidation of N in atmosphere and release of SO2 Greenhouse effect - impact release 10^20 g of CO2 into atmosphere, remaining for 1000-100,000 years |
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What was the Tunguska event?
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enormously powerful explosion that occurred in Russia
explosion caused by the air burst of a large meteoroid/comet fragment above the earth's surface |
