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23 Cards in this Set
- Front
- Back
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continental shelf
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gently sloping submerged surface extending from the shoreline toward the deep-ocean basin
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Passive continental margins
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-found alon coastal areas
-little volcanoism -contain mineral deposits -undisturbed sediment |
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Active Continental Margins
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-where oceanic lithosphere is subducted beanth edge of a continet
-narrow margin -deformed sediments -Pacific Rim |
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Continental Slope
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deep structure
-marks boudary between continental crust and oceanic crust |
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Continental Rises
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-gradual incline
-slope drops to around 1/3 degrees -thick sediment moving downslope |
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deep ocean trenches
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-long narrow creases in the seafloor
-form in deepest parts of seafloor |
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Abyssal Plains
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-deep flat feature
-coast of Argentina - found in all oceans |
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seamounts
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-shield volcanoes that rise hundreds of meters above surrounding topography
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oceanic ridge
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-broad linear swell
-elevated position -extensive faulting -associated earthquakes -largest topographic feature |
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rift zones
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narrow areas where seafloor spreading occurs
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sheeted dike complex
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when new dikes intrude older dikes which are still warm and weak
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pillow basalts
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tube shaped protuberances, forward motion occurs as lava accumulates behind congealed margin and breaks through
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continental rift
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elongated depression in which entire thickness of the lithosphere was deformed
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mantle plume
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hotter than nomral mantle rock that has a mushroom shaped head, hundreds of km in diameter
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turbidity current
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downslope movement of dense , sediment-laden water created when sand and mud on the continental shelf and slope are dislodged.
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Black Smoker
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a hydrothermal vent on the ocean floor that emits a black cloud of hot metal-rich water
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Ophiolite Complex
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sequence of rocks that make up the oceanic crust (pillow basalts, sheeted dikes, gabbro)
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Turbidite
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turbidity current deposit characterized by graded bedding
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Submarine canyon
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seaward extension of a valley that was cut on the continental shelf during the time when sea level was lower.
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hot spot
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concentration of heat in the mantle, capable of producing magma that in turn extrudes onto Earth's surface
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Atoll
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coral island consisting of nearly continuous ring of coral reef surrounding a central lagoon
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seamount
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isolated volcanic peak that rises at 1000 meters above the deep ocean floor
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guyot
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flat topped seamount
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