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Published byJulie Patrick Modified over 9 years ago
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DEVELOPMENT OF A THEORY Page 47 of INB
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ESSENTIAL QUESTION Explain the evidence used to support seafloor spreading.
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SONAR Echo sounding technology developed during WWII used to map the ocean floor. Showed mountains in the middle of the ocean. Called mid-ocean ridge (MOR)
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SEAFLOOR SPREADING New crust forms along the MOR as older crust is pulled away. New crust forms as pillow lava Sediment are deposited on older rocks to make bottom smooth
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HOW DID A COMPASS PROVE SEAFLOOR SPREADING? Outer core of Earth creates a magnetic field Reverses every hundred thousand to few million years
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HOW DID A COMPASS PROVE SEAFLOOR SPREADING? Rocks act like a compass and align with the magnetic field Parallel patterns in the magnetic signature on both sides of the MOR
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HOW DID A COMPASS PROVE SEAFLOOR SPREADING? Each pair of stripes had similar composition, age, and magnetic character This proved seafloor spreading. Which proved the continents were moving.
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LESSON 2-3 Seafloor Spreading Theory
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