Physical Geology: Igneous, Andesitic and rhyolitic debris
What Types of Rock are made by Volcanic Eruptions? (Part 3 of 6)
IgnRx-How to Observe and Name Porphyritic Igneous Rock
What is ANDESITE LINE? What does ANDESITE LINE mean? ANDESITE LINE meaning & explanation
Andesite ( or ) is an extrusive igneous, volcanic rock, of intermediate composition, with aphanitic to porphyritic texture. In a general sense, it is the intermediate type between basalt and rhyolite, and ranges from 57 to 63% silicon dioxide (SiO2) as illustrated in TAS diagrams. The mineral assemblage is typically dominated by plagioclase plus pyroxene or hornblende. Magnetite, zircon, apatite, ilmenite, biotite, and garnet are common accessory minerals. Alkali feldspar may be present in minor amounts. The quartz-feldspar abundances in andesite and other volcanic rocks are illustrated in QAPF diagrams.