Earth Sciences 1070A/B Lecture Notes - Lecture 3: Hydrogen Sulfide, Volatiles, Crystallization

• School: Western University
• Department: Earth Sciences
• Course: Earth Sciences 1070A/B
• Professor: Natalie Pietrzak- Renaud

Document Summary

Molten silicate material igneous rocks form at high temps. When solid rock melts, rocks form when minerals crystalize from magma (cooled) Chemistry of magma and initial temp = what minerals form. Mag(cid:373)a o(cid:396)igi(cid:374)s = (cid:271)etw 50 a(cid:374)d 250(cid:373) (cid:271)elow ea(cid:396)th"s su(cid:396)fa(cid:272)e. 3. 0. 1 effects of temp, pressure, volatiles & solids. Solids = denser than liquid increase in pressure (compact crystalline structure instead of disordered liquid: increase temp = breaks down atom bonds melts. Ea(cid:396)th"s i(cid:374)te(cid:396)io(cid:396) = (cid:374)ot (cid:373)olte(cid:374) bc high pressures of overlying buried rocks compress into more crystalline state: if pressure decreased (fissure crack) = solid may melt. Magma naturally contains dissolved volatiles / gas bubbles (co2, water, hydrogen sulphide etc: lowers melting temp of silicate minerals, more volatiles = lower melting temp, solids = can lower melting melting temps. Melting temp of most rocks = lower than temps at which individual minerals would melt: bc many minerals in rocks (all diff. melting temps)