Asked by sigma sam

what happens to the plates during a divergent boundary

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Answered by GPT-5 mini AI
At a divergent plate boundary the two plates move away from each other. The main things that happen are:

- Mantle upwelling and decompression melting: Hot asthenosphere rises to fill the gap; lower pressure causes partial melting and magma forms.
- Creation of new crust: Magma erupts or intrudes and solidifies as new lithosphere (usually basaltic oceanic crust). This is called seafloor spreading at mid-ocean ridges.
- Formation of ridge/rift features: In the ocean you get a mid-ocean ridge; on continents you get rift valleys (e.g., the East African Rift) that may later become new ocean basins.
- Faulting and earthquakes: Tensional stress produces normal faults and shallow, generally moderate earthquakes along the rift or ridge.
- Hydrothermal activity and volcanism: Volcanic eruptions and hydrothermal vents are common at spreading centers and support unique ecosystems.
- Magnetic and age patterns: Newly created crust records Earth's magnetic field, producing symmetrical magnetic stripe patterns and progressively older crust away from the ridge.

Rates vary from a few mm to several cm per year (e.g., Mid-Atlantic ~2–3 cm/yr, East Pacific Rise faster). In short: divergent boundaries build new lithosphere as plates pull apart.