* Divergent plate boundaries are where tectonic plates move apart. This movement creates space, allowing hot material from the Earth's mantle to rise.

* Decompression melting occurs when the pressure on the rising mantle rock decreases. As pressure decreases, the melting point of the rock lowers, causing it to melt.

* Rock recompression freezing is the opposite process. When rock is compressed, its melting point increases, making it more likely to solidify.

In summary:

* At divergent plate boundaries, the movement of plates leads to decompression of the mantle rock.

* This decompression lowers the rock's melting point, causing it to melt and form magma.

Let me know if you have any other questions!