GEOL 104 Lecture 7: Sept29

• School: Queen's University
• Department: Geological Sciences and Geological Engineering
• Course: GEOL 104
• Professor: Daniel Layton- Matthews

Document Summary

Igneous rocks part 2: why melts (magma and lava) form, melt movement, composition of melts: same in magma vs lava. Intrusive and extrusive igneous formation: different time span to crystallize so create different things: different igneous rocks. Form as molten rock cools and solidifies: parent material of igneous rocks is magma. Forms from partial melting of rocks inside earth: magma that reaches the surface is called lava, melts can cool above or below ground. Extrusive igneous rocks cool quickly at the surface. Lava flows streams or mounds of cooled melt: pyroclastic debris cooled fragments. Intrusive igneous rocks rocks cool slowly underground: more intrusive than extrusive igneous rocks. Intrudes into pre-existing wall rock: columns and thin sheets, magma chamber solidifies, also called plutonic rock. Line = solidus point at which first liquid will be produced. Role of pressure: pressure increases with depth, melting occurs at higher temperatures at depth due to higher confining pressure, when confining pressures drop, decompression melting occurs.