Final answer:
When a rock is partially melted, the resulting melt's chemistry can differ from that of the original rock, influenced by the preferential melting of different minerals. This affects the characteristics of the igneous rock that forms upon cooling. Factors such as temperature, pressure, and water content influence these processes.
Step-by-step explanation:
When a rock is partially melted, the chemistry of the melt (liquid) that forms can typically have a different composition from the original rock. The melting process often involves the preferential melting of certain minerals over others due to differences in melting points. The resulting magma or lava can be enriched in these elements, which will eventually influence the chemistry of the igneous rock that forms from the cooled magma or lava.
Igneous rocks are one of the three basic types of rocks classified by geologists based on their mode of formation. They are generally created through the cooling and solidification of magma or lava, as observed in basaltic eruptions. Minerals crystallize from the cooling melt and interlock to form the solid rock. When lava cools on the Earth's surface, it forms an extrusive igneous rock.
The specific conditions under which a rock melts, such as temperature and pressure, as well as the presence of substances like water, can greatly affect the melting point and the resultant chemical composition of the melt. These factors are critically important in determining the characteristics of the igneous rock that ultimately forms.