Magmaerilaistuminen

Magmaerilaistuminen, a Finnish term, translates to "magma differentiation" in English. It is a fundamental geological process that describes the changes in the composition of magma as it cools and solidifies. This process occurs because different mineral components crystallize at different temperatures. As magma cools, minerals with higher melting points will crystallize first and settle out of the remaining liquid magma. This removal of early-formed minerals changes the chemical composition of the residual magma, making it progressively enriched in elements that form minerals with lower melting points.

There are several mechanisms that drive magma differentiation. Fractional crystallization is the most significant, where the separation of solid crystals from the melt, often through gravitational settling or mechanical sorting, leads to a change in magma composition. Assimilation, where the magma incorporates and melts surrounding rock, can also alter its composition. Finally, magma mixing, the blending of two or more magmas with different chemical compositions, can produce a hybrid magma with intermediate properties.

The products of magma differentiation are diverse igneous rocks. For example, a mafic magma that undergoes significant differentiation might eventually produce felsic rocks like granite, while the early-formed crystals could form mafic rocks like gabbro. Understanding magma differentiation is crucial for interpreting the origin and evolution of igneous rocks and for understanding processes within the Earth's crust and mantle.