anorthosite
/əˈnɔːθəsʌɪt
/noun [mass noun] Geology
A granular igneous rock composed largely of labradorite or another plagioclase.Because of the preponderance of the mineral anorthite (a calcium-rich variety of the mineral plagioclase feldspar) this rock type is called anorthosite....
- Coarse-grained anorthosite is the predominant rock type in these bodies.
- The plagioclase crystals would have formed subcircular lenses of anorthosite that punctuated background chromite accumulation.
Origin
Mid 19th century: from French anorthose 'plagioclase' + -ite1.