Classification of Igneous Rocks Figure 2 1 a

Classification of Igneous Rocks Figure 2 -1 b. Method #2 for plotting a point

(a) The rock must contain a total of at least 10% of the minerals

Classification of Igneous Rocks Figure 2 -2. A classification of the phaneritic igneous rocks.

Classification of Igneous Rocks Figure 2 -3. A classification and nomenclature of volcanic rocks.

Classification of Igneous Rocks Figure 2 -4. A chemical classification of volcanics based on

Classification of Igneous Rocks Figure 2 -5. Classification of the pyroclastic rocks. a. Based

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Classification of Igneous Rocks Figure 2 -1 a. Method #1 for plotting a point with the components: 70% X, 20% Y, and 10% Z on triangular diagrams. An Introduction to Igneous and Metamorphic Petrology, John Winter, Prentice Hall.

Classification of Igneous Rocks Figure 2 -1 b. Method #2 for plotting a point with the components: 70% X, 20% Y, and 10% Z on triangular diagrams. An Introduction to Igneous and Metamorphic Petrology, John Winter, Prentice Hall.

(a) The rock must contain a total of at least 10% of the minerals below. Renormalize to 100% Q Quartzolite 90 90 Quartz-rich Granitoid lds Fe Alkali Fs. Quartz Syenite Alkali Fs. Syenite 20 Alk ali lite Granodiorite Granite na par Gra n ite 60 To Classification of Igneous Rocks 60 20 5 10 A Quartz Monzonite Quartz Syenite Monzonite (Foid)-bearing Syenite Monzonite 35 Quartz Monzodiorite 65 Monzodiorite (Foid)-bearing Monzodiorite 10 bro Ga b (Foid) Monzodiorite (Fo e it en Sy (Foid) Monzosyenite id) (Foid)-bearing Alkali Fs. Syenite Figure 2 -2. A classification of the phaneritic igneous rocks. a. Phaneritic rocks with more than 10% (quartz + feldspar + feldspathoids). After IUGS. 60 60 (Foid)olites F Qtz. Diorite/ Qtz. Gabbro 5 Diorite/Gabbro/ 90 Anorthosite P 10 (Foid)-bearing Diorite/Gabbro

Classification of Igneous Rocks Figure 2 -2. A classification of the phaneritic igneous rocks. b. Gabbroic rocks. c. Ultramafic rocks. After IUGS. Olivine Dunite urg Ha Lherzolite hr rzb Peridotites We ite 90 40 (c) Pyroxenites Olivine Websterite Orthopyroxenite 10 10 Orthopyroxene Websterite Clinopyroxene

Classification of Igneous Rocks Figure 2 -3. A classification and nomenclature of volcanic rocks. After IUGS.

Classification of Igneous Rocks Figure 2 -4. A chemical classification of volcanics based on total alkalis vs. silica. After Le Bas et al. (1986) J. Petrol. , 27, 745 -750. Oxford University Press.

Classification of Igneous Rocks Figure 2 -5. Classification of the pyroclastic rocks. a. Based on type of material. After Pettijohn (1975) Sedimentary Rocks, Harper & Row, and Schmid (1981) Geology, 9, 40 -43. b. Based on the size of the material. After Fisher (1966) Earth Sci. Rev. , 1, 287 -298.