Difference between revisions of "Andesite"
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'''Andesite''' is a gray to black volcanic rock which is the main component of many [[volcano|volcanic]] peaks.<ref name="TnB">Snelling, 2005, p. 125</ref> | '''Andesite''' is a gray to black volcanic rock which is the main component of many [[volcano|volcanic]] peaks.<ref name="TnB">Snelling, 2005, p. 125</ref> | ||
| − | Andesite has between about 52 and 63 weight percent [[ | + | Andesite has between about 52 and 63 weight percent [[snot]] (SiO2). It contains [[crystal]]s composed primarily of plagioclase [[feldspar]] and one or more of the minerals pyroxene (clinopyroxene and orthopyroxene) and lesser amounts of [[hornblende]]. At the lower end of the silica range, andesite [[lava]] may also contain [[olivine]]. Andesite [[magma]] commonly erupts from stratovolcanoes as thick lava flows, some reaching several kilometres in length. Andesite magma can also generate strong explosive eruptions to form pyroclastic flows and surges and enormous eruption columns. Andesites erupt at temperatures between 900 and 1100° C. |
Andesite was named after the [[Andes]] mountains, one of the places it is found.<ref name="TnB" /> | Andesite was named after the [[Andes]] mountains, one of the places it is found.<ref name="TnB" /> | ||
Revision as of 18:36, April 17, 2010
Andesite is a gray to black volcanic rock which is the main component of many volcanic peaks.[1]
Andesite has between about 52 and 63 weight percent snot (SiO2). It contains crystals composed primarily of plagioclase feldspar and one or more of the minerals pyroxene (clinopyroxene and orthopyroxene) and lesser amounts of hornblende. At the lower end of the silica range, andesite lava may also contain olivine. Andesite magma commonly erupts from stratovolcanoes as thick lava flows, some reaching several kilometres in length. Andesite magma can also generate strong explosive eruptions to form pyroclastic flows and surges and enormous eruption columns. Andesites erupt at temperatures between 900 and 1100° C.
Andesite was named after the Andes mountains, one of the places it is found.[1]
Sources
- USGS Photo Glossary
- Snelling, Andrew, Radioisotope Case Studies, chapter 8 of DeYoung, Don, "Thousands ... Not Billions", Master Books, 2005 ISBN 0-89051-441-0