1.Chapter 4: Igneous Structures and Field Relationships
We covered much of this in the review.
A few topics remain.
2.Figure 4-1. a. Calculated viscosities of anhydrous silicate liquids at one atmosphere pressure, calculated by the method of Bottinga and Weill (1972) by Hess (1989), Origin of Igneous Rocks. Harvard University Press. b. Variation in the viscosity of basalt as it crystallizes (after Murase and McBirney, 1973), Geol. Soc. Amer. Bull., 84, 3563-3592. c. Variation in the viscosity of rhyolite at 1000oC with increasing H2O content (after Shaw, 1965, Amer. J. Sci., 263, 120-153).
3.Structures and Field Relationships
Figure 4-5. Cross sectional structure and morphology of small explosive volcanic landforms with approximate scales. After Wohletz and Sheridan (1983), Amer. J. Sci, 283, 385-413.
5.Figure 4-18. Types of pyroclastic flow deposits. After MacDonald (1972), Volcanoes. Prentice-Hall, Inc., Fisher and Schminke (1984), Pyroclastic Rocks. Springer-Verlag. Berlin. a. collapse of a vertical explosive or plinian column that falls back to earth, and continues to travel along the ground surface. b. Lateral blast, such as occurred at Mt. St. Helens in 1980. c. “Boiling-over” of a highly gas-charged magma from a vent. d. Gravitational collapse of a hot dome (Fig. 4-18d).
6.Figure 4-19. Section through a typical ignimbrite, showing basal surge deposit, middle flow, and upper ash fall cover. Tan blocks represent pumice, and purple represents denser lithic fragments. After Sparks et al. (1973) Geology, 1, 115-118. Geol. Soc. America
Structures and Field Relationships
7.Structures and Field Relationships
Figure 4-9. Development of the Crater Lake caldera. After Bacon (1988). Crater Lake National Park and Vicinity, Oregon. 1:62,500-scale topographic map. U. S. Geol. Surv. Natl. Park Series.
9.Figure 4-24. a. Map of ring dikes, Island of Mull, Scotland. After Bailey et al. (1924), Tertiary and post-tertiary geology of Mull, Loch Aline and Oban. Geol. Surv. Scot. Mull Memoir. Copyright British Geological Survey.