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20 Cards in this Set
- Front
- Back
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What is bathymetry?
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The shape of the seafloor surface
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What are the two major new revelations that mapping out the ocean floor gave?
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1. Seafloor has high mountains and deep valleys
2. There is a tall, long mountain chain (Mid-Oceanic Ridge) |
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What is pelagic sediment
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The skeletal material of plankton and organic matter that rains down to seafloor as "marine snow"
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What is the mineral that was found instead of pelagic sediment around the mid oceanic ridges
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basalt
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What was the commonly accepted belief about the continents and ocean basins?
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They had always been in the same position.
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Why were researchers surprised not find pelagic sediment around the mid-oceanic ridges?
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Because if the Atlantic had existed since the beginning of time, then it should be lleno de pelagic sediment.
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True or False: Heat flow increased as it reached the Mid-Oceanic Ridges.
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True
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Where do most earthquakes occur?
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Along belt lines of mountain ranges or mid-oceanic ridges.
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Who proposed the theory of Sea floor spreading? In what Year?
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Harry Hess - 1950
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What are the three testable predictions of Sea-floor spreading?
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1. if seafloor is created at mid-ocean ridges, seafloor rocks should be youngest at ridge and progressivly older the farther away
2. if seafloor is progressively older with distance, pelagic sediment should be thicker the farther away 3. If oceanic seafloor subducts under cont. lithosphere, then seafloor should entirely consist of basaltic rocks. |
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What quest is most notably referred to as giving great evidence to strengthen Harry Hess' Seafloor spreading argument?
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The Deep Sea Drilling Project
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What was the official ship of the DSDP?
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The Glomar Challenger (1968-1983)
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What happens in paleomagnetism?
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1. Iron bearing minerals crystallize out of melt
2. Crystals align themselves along earth's magnetic field lines 3. During cooling, orientation is frozen into rock 4. Rock records direction of magnetic field |
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What are the problems with Paleomagnetism?
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1. Few mineral grains align themselves
a. lava too viscous b. grains too large |
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How is magnetization recorded in rocks?
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It is recorded in the orientation of the atoms.
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When did the last reversal of earth's magnetic field happen?
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780,000 yrs ago
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What precedes a magnetic field reversal?
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The magnetic field weakens
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What is a striped pattern?
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magnetic reversals in seafloor basalts symmetrically arranged on each side of the ridge
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What two theories are significant in creating the Theory of Plate Tectonics?
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Theory of Continental Drift
Theory of Seafloor Spreading |
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What are the three differences between Continental Drift and Plate Tectonics?
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1. continental drift says continents moved thru and on top of ocean crust
2. continental drift never had seafloor spreading 3. Tectonics plates are not only continents, but continents and oceanic crust and mantle. Some are only oceanic lithosphere. |
