EARTH121 Lecture Notes - Lecture 3: Igneous Differentiation, Pumice, Olivine

• School: University of Waterloo
• Department: Earth Sciences
• Course: EARTH121
• Professor: Keith Delaney

Document Summary

Ig(cid:374)eous (cid:396)o(cid:272)ks (cid:373)ake up the (cid:271)ulk of ea(cid:396)th"s (cid:272)(cid:396)ust. Except the core, the solid portion of earth is a large mass of igneous rocks and is partially covered by a thin layer of sedimentary and metamorphic rocks. Igneous rocks form as a molten rock cools & solidifies. Pa(cid:396)tial (cid:373)elti(cid:374)g: o(cid:272)(cid:272)u(cid:396)s at (cid:448)a(cid:396)ious le(cid:448)els (cid:449)ithi(cid:374) ea(cid:396)th"s (cid:272)(cid:396)ust & uppe(cid:396) (cid:373)a(cid:374)tle to depths up to. 250km; process which forms magma (a parent material for igneous rocks) Formation of magma brings it to the surface due to buoyancy; occasionally molten rocks break through which produces a volcanic eruption. When magma explosively ejects from a vent, there can be catastrophic eruptions. Some volcanoes are not violent but rather quiet outpourings of fluid lava. Extrusive/volcanic: igneous rocks that form from lava (magma on the surface) Extrusive rocks are abundant in the western americas & many oceanic islands are almost entirely composed of volcanic rocks.