Quiz 7: Intro to Igneous Petrology and Classification

A Gabbro (or Basalt) is composed primarily of

Plagioclase and Clinopyroxene

Given the IUGS QAPF ternary diagram, field 5 is

Tonalite

Alkaline rocks are rich in ___ and/or low in ___ as compared to subalkaline rocks

Na2O+K2O; SiO2

In the IUGS classification system, the term “Essential Mineral” refers to:

The modal minerals used to classify the rock.

Given the IUGS Ultramafic/Mafic ternary diagrams, field A is

Lherzolite

Given the IUGS Ultramafic/Mafic ternary diagrams, field C is

Dunite

Given the IUGS QAPF ternary diagram, field 4 is

Granodiorite

Given the IUGS Ultramafic/Mafic ternary diagrams, field B is

Harzburgite

Ternary AFM diagrams can be used to differentiate between magma series. In the AFM diagram below, igneous rock compositions that fall in field A are termed __________, while those in field B are termed ____-________

Tholeiitic; Calc-Alkaline

Given the IUGS QAPF ternary diagram, field 3 is

Granite