- ALASKA VOLCANO OBSERVATORY GLOSSARY
A crystal that resembles a phenocryst in igneous rock, but is a foreign to the body of rock in which it occurs.
Glossary of volcanic terms. - University of Wisconsin Oshkosh. G. J. Hudak. 2001.
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Xenolith — This article concerns the geologic term, for other uses see: Xenolith (disambiguation) A xenolith (Greek: foreign rock ) is a rock fragment which becomes enveloped in a larger rock during the latter s development and hardening. In geology, the… … Wikipedia
Mount Cayley volcanic field — Coordinates: 50°07′13″N 123°17′26″W / 50.12028°N 123.29056°W / 50.12028; 123.29056 … Wikipedia
Diamond — This article is about the mineral. For the gemstone, see Diamond (gemstone). For other uses, including the shape ◊, see Diamond (disambiguation) … Wikipedia
Lassen Volcanic National Park — IUCN Category II (National Park) … Wikipedia
Cinder Cone and the Fantastic Lava Beds — For the generic cinder cone, see cinder cone. Cinder Cone Cinder Cone is a 700 foot (213 m) high cone of loose scoria … Wikipedia
Nepheline syenite — of the Intrusive Complex of Tanguá, State of Rio de Janeiro, Brasil (Motoki et al., 2011a) Nephelene syenite is a holocrystalline plutonic rock that consists largely of nepheline and alkali feldspar. The rocks are mostly pale colored, grey or… … Wikipedia
Ignimbrite — is a volcanic pyroclastic rock, often of dacitic or rhyolitic composition. Ignimbrite is the deposit of a pumice rich pyroclastic density current, or pyroclastic flow , a hot suspension of particles and gases that flows rapidly from a volcano,… … Wikipedia
Lamprophyre — Lamprophyres (Greek λαµπρός (lamprós) = bright and φύρω (phýro) = to mix) are uncommon, small volume ultrapotassic igneous rocks primarily occurring as dikes, lopoliths, laccoliths, stocks and small intrusions. They are alkaline silica… … Wikipedia
Ultrapotassic igneous rocks — are a class of rare, volumetrically minor generally ultramafic or mafic silica depleted igneous rocks. Ultrapotassic rocks are defined by molar K2O/Na2O >3 in much of the scientific literature. In other papers written as recently as 2005, they… … Wikipedia
Rutile — Catégorie IV : oxydes et hydroxydes Rutile sur Chlorite Carrière de Trimouns, Ariège, France … Wikipédia en Français