Speech 2001 Lecture Notes - Magma Chamber, Igneous Differentiation, Biotite

• School: Western University
• Department: Speech
• Course: Speech 2001
• Professor: Christine Sprengler

Document Summary

Earth sciences 1022b lecture brief 17 jan 13. Igneous rocks crystallize from molten silicate material called magma that forms at high temperatures and pressures deep in the earth. Magma rises through the crust and either reaches the surface by volcanoes (extrusive) or cools below surface (intrusive). How magmas evolve - according to bowen s reaction series: discontinuous (different molecular structures of olivine [single tetrahedra], pyroxene [single chains], amphibole. [double chains], biotite [sheets]), and continuous (same plagioclase structure) Magma composition can also change through assimilation (pieces of host rock fall into the magma and melt) and magma mixing where one body of magma invades another, producing a composition intermediate between the two. Rock composition: from dark (mafic, less silica) to light (felsic, more silica) minerals.