Changes

Active continental margin becomes the most complicated site of magma generation of Earth. As discussed in previous section, magma generation begins at the slab and [[mantle]] wedge. Partial melting of mantle wedge generates basaltic primitive magma. In island-arc, primitive magma rises to the surface and builds basaltic or andesitic volcano. Igneous processes in island-arc differ with active continental margin in assimilation and fractional crystallization.

Active continental margin becomes the most complicated site of magma generation of Earth. As discussed in previous section, magma generation begins at the slab and [[mantle]] wedge. Partial melting of mantle wedge generates basaltic primitive magma. In island-arc, primitive magma rises to the surface and builds basaltic or andesitic volcano. Igneous processes in island-arc differ with active continental margin in assimilation and fractional crystallization.

Primitive magma generated from the mantle wedge ascent to the boundary of crust and mantle. Due to density contrast, magma from mantle wedge underplates at the base of crust and experiences melting, assimilation, storage, and homogenization (MASH). Assimilation occurs because the crust is molten and enriching the composition of ascending magma. Winter<ref name=Winter>Winter, John D. 2001. An Introduction to Igneous and Metamorphic Petrology. New Jersey: Prentice- Hall Inc.</ref> defines fractionation as mechanical separation of materials with distinct phases. Simplified explanation of fractional crystallization is represented in Bowen reaction series. Magma will ascent from the base of the crust when faults creating fractures for magma migration. This requirement may occur in thinning area.

Primitive magma generated from the mantle wedge ascent to the boundary of crust and mantle. Due to density contrast, magma from mantle wedge underplates at the base of crust and experiences melting, assimilation, storage, and homogenization (MASH). Assimilation occurs because the crust is molten and enriching the composition of ascending magma. Winter<ref name=Winter>Winter, J. D. 2001, An Introduction to Igneous and Metamorphic Petrology. New Jersey: Prentice-Hall Inc.</ref> defines fractionation as mechanical separation of materials with distinct phases. Simplified explanation of fractional crystallization is represented in Bowen reaction series. Magma will ascent from the base of the crust when faults creating fractures for magma migration. This requirement may occur in thinning area.

Assimilation and fractional crystallization of magma in the continents depends on the type of the crust. Continental crust itself is generally divided as upper and lower parts, represented with distinctive composition as previously discussed. With several possibilities of interaction, assimilation and fractional crystallization of magma have different Sr, Nd, Pb, and O isotopic signature. The use of Sr, Nd, and Pb data for interpreting young continental crust may trigger misleading result. Since young continental crust may have slightly different composition with the primitive magma, the data will show that contamination doesn’t occur. Winter<ref name=Winter /> states that assimilation and fractional crystallization in the deep-level generates magma with higher concentrations of K2O, Rb, Cs, Ba, Th, and Light Rare Earth Elements (LREE). Assimilation in active continental margin depends on temperature, composition, and thickness of the crust.

Assimilation and fractional crystallization of magma in the continents depends on the type of the crust. Continental crust itself is generally divided as upper and lower parts, represented with distinctive composition as previously discussed. With several possibilities of interaction, assimilation and fractional crystallization of magma have different Sr, Nd, Pb, and O isotopic signature. The use of Sr, Nd, and Pb data for interpreting young continental crust may trigger misleading result. Since young continental crust may have slightly different composition with the primitive magma, the data will show that contamination doesn’t occur. Winter<ref name=Winter /> states that assimilation and fractional crystallization in the deep-level generates magma with higher concentrations of K2O, Rb, Cs, Ba, Th, and Light Rare Earth Elements (LREE). Assimilation in active continental margin depends on temperature, composition, and thickness of the crust.