Classification of Igneous Rocks Worksheet.

CLASSIFICATION OF IGNEOUS ROCKS The classification of igneous rocks is based on composition, for example, silica content [high silica to low silica]: felsic, intermediate, mafic, ultramafic. Also texture: fine-grained texture (aphanitic) and coarse-grained texture (phaneritic). Using the descriptions below, determine the names of the rock listed below. Remember the resources listed in your textbook: 6.6 How Do You Describe an Igneous Rock? Geology at a glance: Formation of Igneous Rocks on page 179 Figure 6.19 Figure 6.20 I am a fine-grained rock and contain equal amounts of K-feldspar, quartz, sodiumplagioclase, and a little bit of biotite. What is my name? I am a coarse-grained rock and contain mostly plagioclase (~75%) and hornblende (~25%), with a trace amount of quartz, and augite (pyroxene). What is my name? I am a fine-grained rock and am made up of calcium-plagioclase, augite, and a bit of olivine. What is my name? I am a fine-grained rock and contain mostly plagioclase and hornblede with trace amounts of K-feldspar, quartz, and augite (pyroxene). What is my name? I am a coarse -grained rock and contain mostly calcium-plagioclase and augite with some olivine. What is my name? I am a coarse-grained rock and contain equal amounts of K-feldspar, quartz, sodiumplagioclase, and a little bit of biotite. What is my name? I am fine-grained contain mostly olivine with some augite and a trace amount of calcium-plagioclase. What is my name? I am coarse-grained and found in the Earth’s mantle and contain mostly olivine and a bit of augite, with a trace of calcium-plagioclase. What is my name?