Evidence for past reversals of Earth's magnetic field comes from:

Question

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Magnetized rock in layers produced by seafloor spreading provides evidence for past reversals of Earth's magnetic field. As magma rises at mid-ocean ridges and solidifies into new rock, the orientation of magnetic minerals in the rock aligns with Earth's magnetic field at the time. As the plates move apart, new rock is added on either side, creating a record of Earth's magnetic field history. Scientists can study the magnetic orientation of these rocks to determine when and how often the magnetic field has reversed in the past.

Evidence for Past Reversals of Earth's Magnetic Field Comes From