ERTH 2415 Lecture Notes - Lecture 8: Volcanic Glass, Asthenosphere, Transform Fault

• School: Carleton University
• Department: Earth Sciences
• Course: ERTH 2415
• Professor: Jason Mah

Document Summary

Composition of the crust: as a result of planetary differentiation, 8 elements form 98% of the crust, silicon and oxygen account for = 75, very dense: Inner core = solid iron: liquid iron, dense, mantle: iron and magnesium, less dense, silicon and oxygen. Si-o tetrahedron molecule: four oxygen ions surrounding a much smaller silicon ion, tetrahedrons combine to form rings, chains, sheets and 3d structures. Igneous rocks form by cooling and solidification from hot molten rock material. Intrusive igneous rocks: cooling at depth: intrusive igneous rocks, slow cooling, large grains, most magmas solidify at depth and are later exposed by erosion. Extrusive igneous rocks: cooling at the surface: extrusive (synonym: volcanic) igneous rocks, fast cooling, small grains, contact with the atmosphere or water. Igneous rocks are classified according to: cooling environment. Intrusive vs extrusive rocks: mineral composition expressed as % sio2, properties closely related to, macroscopic features, color, texture: shape, size and arrangement of mineral grains, magma behaviour.