EARTH121 Final: Earth 121 Condensed Exam Review

• School: University of Waterloo
• Department: Earth Sciences
• Course: EARTH121
• Professor: Keith Delaney

Document Summary

Igneous rocks form when magma cools and solidifies: magma originates from partial melting of pre-existing rocks, crystallization can be fast (glass), slower (aphanitic), or even slower (phaneritic textures). Igneous minerals occur in groups predicted by bowen"s reaction series: magmatic differentiation leads to the great variety of igneous rock types. Igneous rocks are classified by their mineral composition (chemistry) and texture (grain size). Understand the terms/concepts: intrusive, extrusive, felsic, basic, silica tetrahedron, bowen"s reaction series, aphanitic, porphyritic, phaneritic, ferromagnesian minerals, nonferromagnesium minerals, phenocryst. Contrast igneous rock textures that form when cooling is rapid with those when cooling is slow. What are more typical mineral groupings formed by crystallization at high temperature: quartz, k-feldspar, biotite or pyroxene, ca-rich plag feldspar, na-plag feldspar, k-feldspar, hornblende or pyroxene, hornblende, k-rich feldspar. A dark, fine-grained igneous rock with a few large crystals of pyroxene and. Summary: eruption style and volcano morphology is mainly determined by magma composition, t, dissolved gases.