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Convergent – Oceanic / Continental
Convergent – Oceanic / Oceanic
🌊 Evidence of Plate Tectonics
Explore the two evidence that supports the theory of plate tectonics, which are seafloor spreading and magnetic striping.
🌊 Seafloor Spreading
New oceanic crust is continuously formed as lava erupts from the mid-ocean ridge, cools and solidifies. What do you notice about the pattern about age of rocks?
🧲 Magnetic Striping
Basaltic rocks contain iron-rich magnetic minerals. When the iron-rich lava erupts from the centre of mid-ocean ridge, cools and solidifies, its magnetic materials point towards the Earth's magnetic North and record the earth's polarity at that time. How does the magnetic pattern look like on the seafloor?
🔗 Pulling The Evidence Together
How do both of these evidence support the Plate Tectonics theory?
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Time:
Legend:
New oceanic crust
Older oceanic crust
Normal polarity (N)
Reversed polarity (R)
→Plate movement
Key Points:
• Magma rises and forms new oceanic crust at the ridge.
• As lava cools, magnetic minerals align with Earth's magnetic field.
• Each new layer records the magnetic polarity at that time.
• Symmetrical stripes on both sides show that seafloor spreading has occurred.
• Magma rises and forms new oceanic crust at the ridge.
• As lava cools, magnetic minerals align with Earth's magnetic field.
• Each new layer records the magnetic polarity at that time.
• Symmetrical stripes on both sides show that seafloor spreading has occurred.
📖 Explanation
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