Question

Define a primary magma.

Answer 1

Primary Magma - John Seach - Volcano Live Primary Magma - John Seach. Primary magma is produced by the direct melting of the earth's mantle. Magmas with the highest Mg concentrations will be most representative of the original mantle. A lower Mg level indicates the magma has undergone modification by fractional crystallization, assimilation, or magma mixing.