Zusammenfassung der Ressource
Frage 1
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Why are earthquakes rare in ocean basins away from MORs?
Frage 2
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Why is there a positive heat flow over the axial rift of an MOR?
Frage 3
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How have satellites provided evidence for sea floor spreading?
Frage 4
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[blank_start]Transform[blank_end] faults displace mid-ocean ridges.
They form [blank_start]perpendicular[blank_end] to the axial rift.
Frage 5
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Seismic [blank_start]tomography[blank_end] has been used to provide evidence for mantle plumes and hot spots by taking [blank_start]3D[blank_end] images of heat flow to show areas of [blank_start]high[blank_end] heat flow compared to cooler ones.
Frage 6
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Label the image to show the formation of island chains and seamounts over a hotspot.
Frage 7
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How does a chain of islands and seamounts develop over a hotspot?
Rising magma creates an [blank_start]island[blank_end].
The plate moves over the [blank_start]hotspot[blank_end].
The mantle plume is [blank_start]stationary[blank_end].
Older islands [blank_start]sink[blank_end] and are eroded.
Antworten
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island
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hotspot
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stationary
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sink
Frage 8
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What is a mantle plume?
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A stationary area of high heat flow in the mantle which rises from great depths and produces magma that feeds hot spot volcanoes.
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A body of lower density buoyant material rising upwards.
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The surface expression of a mantle plume.
Frage 9
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Using the fit of Africa and S. America describe the evidence for the movements of continents over time.
Fit of the [blank_start]continents[blank_end]
- Fit along edge of continental [blank_start]shelf[blank_end].
- Few [blank_start]overlaps[blank_end] due to younger rock deposited.
- Few gaps due to [blank_start]erosion[blank_end].
Rock types
- Matching [blank_start]rock[blank_end] sequences across the join of the continents
- Same age of rocks across the [blank_start]join[blank_end]
eg. Precambrian - cratons
eg. Carboniferous - [blank_start]glacial deposits[blank_end]
Mountain chains
- Same trend of mountain [blank_start]belts[blank_end] across the join of the continents
- structures such as folds / faults match up
- same rock types in the mountain belt across the join
- same [blank_start]age[blank_end] of mountains across the join
Fossils
- outcrops of fossils match up / same fossils on different continents
- fossils that could not have crossed an ocean the same on both continents
eg reptile - [blank_start]Mesosaurus[blank_end]
eg plants - [blank_start]Glossopteris[blank_end]
Glaciations
- direction of [blank_start]striations[blank_end] shows movement of ice and the striations match up
- glacial [blank_start]erratics[blank_end] can be found on both continents
- glacial rocks match up across the join
- Carboniferous ice [blank_start]sheet[blank_end] can be seen across Africa and South America
Antworten
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continents
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shelf
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overlaps
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erosion
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rock
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join
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glacial deposits
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belts
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age
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Mesosaurus
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Glossopteris
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striations
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erratics
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sheet
Frage 10
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Fossils found in Africa and S. America used as evidence for continental drift:
Reptile = [blank_start]Mesosaurus[blank_end]
Plant = [blank_start]Glossopteris[blank_end]
Frage 11
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Label the diagram of an MOR.
Frage 12
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Label the diagram of the oceanic-continental convergent plate margin.
Frage 13
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Label the diagram of the continental-continental convergent plate margin.
Frage 14
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Label the diagram of a oceanic-oceanic convergent plate margin.
Antworten
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sea level
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subducting oceanic crust
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Benioff zone
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partial melting
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volcanic island
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oceanic crust
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deep sea trench
Frage 15
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Give examples of the different types of plate margins:
Divergent: [blank_start]Mid-Atlantic Ridge[blank_end]
Oceanic-Continental Convergent: [blank_start]Nazca[blank_end] and [blank_start]South American[blank_end]
Continental-Continental Convergent: [blank_start]Indian[blank_end] and [blank_start]Eurasian[blank_end]
Oceanic-Oceanic Convergent: [blank_start]Pacific[blank_end] (subducting) and [blank_start]Philippine[blank_end]
Conservative: [blank_start]Pacific[blank_end] and [blank_start]North American[blank_end]
Antworten
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Mid-Atlantic Ridge
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Nazca
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South American
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Indian
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Eurasian
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Pacific
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Philippine
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Pacific
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North American