GEL 130QR- Midterm Exam Guide - Comprehensive Notes for the exam ( 16 pages long!)
Document Summary
Igneous rocks form either deep beneath the earth"s o o surface from magma or cool above the surface when lava cools. Magma is underground and lava is aboveground. Explain how are igneous rocks classified? (according to their composition and texture) Composition granitic (felsic), andesitic (intermediate), basaltic (mafic), ultramafic. Texture - glassy, porphyritic (two different crystal sizes), phaneritic (coarse-grained), Vesicular (voids left from air bubbles), pyroclastic (fragmental), and aphanitic (fine-grained). Differentiate between felsic (granitic) and mafic (basaltic) igneous rocks felsic igneous rocks are composed of light-colored felsic rocks that is 70% silica while mafic igneous rocks are composed of dark-colored with 45% dark silica material. Be able to work with the igneous rock classification chart (chart will be provided during the exam) List three factors that determine the nature of a volcanic eruption. Temperature the hotter it creates a more fluid lava, the cooler it is the higher the viscosity o o.
