4.11 Questions

Assemblage Question: According to the Mineralogical Phase Rule the maximum number of minerals that that are likely occur together at equlibrum at a random T and P is equal to the minimum number of chemical components needed to describe the chemical compositions of all the minerals in a rock system. Using this rule, which of the following mineral assemblages may occur at equilibrium in a metamorphic rock of the appropriate bulk composition? Check all the assemblages that follow the Mineralogical Phase Rule and the press the "Submit Answer" button.

Fo-En-Qz
Fo-Ath
Fo-En-Tlc-Qz
Atg-Tlc-Qz
En-Ath-Tlc
Fo (alone)
Fo-Atg-Ath-Tlc-Qz

Submit Answer

Yes! You have correctly identified the minimum number of chemcal components needed to describe each mineral assemblage. All the minerals can be plotted on a ternary diagram, but some of them (Fo-En-Qz and En-Ath-Tlc) occur along a line and can be described by two componts.

Metamorphic Rocks Topics List No. Some of your choices are wrong. Try again or press this button to see a graph of these mineral compositions.

Show Graph