Questions and Answers
What are the underwater mountains called?
How did scientists determine the location and size of underwater mountain chains?
Sonar
How do mid ocean ridges form?
Convection currents bring molten material up to the upper mantle, rising through fault cracks between diverging oceanic plates.
Where do mid ocean ridges form?
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Who was Harry Hess and what did he study?
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What radical idea did Hess propose?
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Where does sea floor spreading begin?
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What happens to oceanic crust at deep ocean trenches?
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What is this process called?
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What force pulls oceanic crust down beneath the trench?
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Explain the process of sea floor spreading.
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How does sea floor spreading support the idea of continental drift?
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What technologies helped Hess prove his theory of sea floor spreading?
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What happens to the rock when oceanic crust is formed?
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What is this process called?
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What happens to oceanic crust at deep ocean trenches?
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Every __________ (___________) years, new rock forms at the mid ocean ridge and sinks into a trench recycling itself.
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Why is the Pacific Ocean shrinking?
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What are the three kinds of tectonic plates?
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These different types of boundaries occur on land and in the ocean all around the world. You should be able to use symbols provided to identify the different types of boundaries such as: a. ________________ between the Eurasian and Pacific Plates.
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What landforms are created when two ocean plates diverge? _____________.
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What landforms are created when two continental plates diverge? _____________.
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What landforms are created when an oceanic and a continental plate converge? _____________.
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Study Notes
Mid-Ocean Ridges
- Underwater mountain chains are known as mid-ocean ridges.
- Form along divergent boundaries where tectonic plates pull away from each other.
- Found in every ocean around the globe.
Sea Floor Spreading
- Occurs at mid-ocean ridges where magma rises from the mantle, creating new oceanic crust.
- The process supports continental drift, as new crust formation pushes adjacent crust outward.
- Takes place approximately every 200 million years as new rock forms, moves, and sinks into trenches.
Key Figures and Proposals
- Harry Hess was an American geologist who studied mid-ocean ridges and proposed the concept of sea floor spreading.
- Hess's radical idea suggested that new crust is continually added, affecting plate movement.
Mechanisms of Oceanic Crust
- Oceanic crust sinks back into the mantle at deep ocean trenches through a process called subduction.
- The force of gravity pulls the crust down into these trenches.
Technologies Advancing Study
- During Hess's lifetime, advancements such as sonar, submarines, and deep ocean drilling tools emerged, aiding in the proof of sea floor spreading.
- These technologies were pivotal in understanding oceanic structures, unlike during Wegener's time.
Tectonic Plates and Boundaries
- There are three primary types of tectonic plate boundaries:
- Convergent boundaries (plates move towards each other)
- Divergent boundaries (plates move apart)
- Transform boundaries (plates slide past each other)
- Examples of boundaries include:
- Convergent: Eurasian and Pacific Plates
- Divergent: North American and Eurasian Plates
- Transform: Sections of North American and Pacific Plates.
Landforms Related to Plate Interaction
- Diverging ocean plates create mid-ocean ridges and mountain ranges.
- Diverging continental plates form rift valleys and volcanoes.
- Converging oceanic and continental plates lead to subduction zones and volcanic islands.
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Description
Explore the fascinating topic of sea floor spreading with these flashcards. Learn about mid-ocean ridges, the technology used to locate these underwater mountains, and how they form. Perfect for students studying oceanography or related subjects.
