Origin of andesiteafter Andes (Mountains)
a dark-colored, fine-grained, extrusive igneous rock consisting chiefly of plagioclase feldspars with some biotite, hornblende, or pyroxene
A gray, fine-grained volcanic rock consisting chiefly of plagioclase feldspar and one or more mafic minerals.
Origin of andesiteAfter the Andes
- All the volcanic rocks of these islands are submarine stratified tuffs which are penetrated here and there by andesite or diabase dikes.
- The lavas and ashes ejected by these volcanoes consist of liparite, dacite, andesite and basalt.
- Keechelus andesite series 4000 ft.
- The rolled crystals of sapphire occur, with garnet and other minerals, in glacial deposits, and have probably been derived from dykes of igneous rocks, like andesite and lamprophyre.
- At the close of the Eocene period great eruptions of augite-andesite took place from two fissures which ran along the west coast.