Based on the bulk rock composition, a certain mineral will crystallize before another based on the related binary phase diagram. If petrologists can see that one mineral crystallized before another, they can determine what side of the eutectic the bulk rock composition is on to cause the crystallization pattern observed.

As we learned in class, individual minerals have higher melting points than a combination of multiple minerals, which lowers the melting point of the system. The combination of Na2O+K2O, halogens, and Ca in the melt likely lowers the melting point to allow the temperature of the lava to be much lower than other lava compositions like basalts.

We learned in class that one way that the composition of magma can change during ascension is through assimilation of country rock, where the magma melts the surrounding rock and incorporates it into the melt. However, the expulsion of alkali-rich fluids blocks magma from entering fractures and incorporating the country rock.

Due to mantle under continents being fertile and enriched in incompatible elements. The lower percent of partial melting at the beginning of the formation of a parental melt will contain a higher concentration of incompatible elements that readily enter the melt, as they are incompatible with their source rock. As melting continues, compatible elements will dilute the concentration of incompatible elements.

Represented in binary phase diagrams by the solvus line, which the rock travels on after crystallization and minerals are altered because they can't continue to exist in the current configuration at certain temperatures and pressures.

This can be represented in P-T diagrams, where minerals can be stable only under certain pressure and temperature conditions, like olivine, but once they reach the surface and lower pressure, conditions are favored for transformations to other minerals or weathering occurs readily.

Possibly an example of replacement, especially in the case of Mg and Fe.

As melts crystallize in the crust, incompatible minerals like alkaline minerals will remain in the melt, which can move elsewhere, leaving a pluton to crystallize that is depleted in incompatible elements. Thus, plutonic carbonatites will be missing incompatible elements and fluid mobile elements that appear in the composition of erupted carbonatites.

Related to previous annotation, at continental rifts, mantle magma below is enriched in volatiles because it is fertile, so carbonatites can form in conjunction with alkaline magmas.

Dykes and veins are intrusions of magma that cross cut the layers that it goes through. Plugs are part of the volcanic plumbing system, where magma in the volcanic conduits solidifies before it can be erupted. Lavas are the result of magma being erupted from a volcano, usually in an effusive eruption from a shield or scoria cone. Pyroclastic falls occur as a result of explosive eruptions from a stratovolcano.

Igneous rocks are primarily classified on tertiary diagrams that record the percentage of the dominant minerals in the rock. Then the diagram is separated into rock classifications based on ranges of percentages of each mineral. In this case, such high percentages of carbonate minerals in an igneous rock classifies it as a carbonatite because this high percentage makes it distinct from other rocks with lower carbonate content.

Carbonatites can form as a result of nearby alkaline magmas because carbonatites and alkaline magmas are immiscible, that is they cannot mix like oil and water so carbonatite magma separates out. The formation of alkaline magmas is tied to mantle melt high in volatiles which make it evolve along a calc-alkaline trend, common in the fertile mantle under continental crust