ESCI 1001 Lecture Notes - Lecture 15: Mid-Ocean Ridge, Long Valley Caldera, Smoky Quartz
Document Summary
Definition: rock that forms when hot molten rock (magma or lave) cools and becomes solid. Magma: is hot molten rock beneath the earths surface which includes suspended minerals and dissolved gases. Lava: magma exposed at the earths surface. Emphasis is on the sizes of crystals in the rock. Phaneritic: can be seen with the naked eye. Aphanitic: crystals are too small to see (or rock is glass). Pegmatitic: crystals larger than 2 cm on average (large). Most magmas/lavas are rich in silica (more than 45%. (na ca fe mg al and k are major cations) Minerals that form are mostly silicates : olivine (single), pyroxene (chain), amphibole (double chain), micas (sheet), feldspar (3d), quartz (3d) Mineral assemblage : how much silica, fe, mg, na, ca, and k. 5 type of extrusive: granite, granodiorite, diorite, gabbro, peridotite. Temperature increases with depth, but so does the melting point of rock. Melting is rare (and by rare i mean rare)
