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Melt Properties. Updates/questions?. Labs: Field trip:18 th or 19 th ? Last lecture’s 3 remaining slides in lab Today’s topics: Magma properties. Melt properties - Internal variables. Composition. Majority of Earth’s minerals are …?. Bill White’s Geochemistry book. Silicates.
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Updates/questions? • Labs: • Field trip:18th or 19th? • Last lecture’s 3 remaining slides in lab • Today’s topics: • Magma properties
Composition Majority of Earth’s minerals are …? Bill White’s Geochemistry book
Silicates http://visionlearning.com/library/modules/mid140/Image/VLObject-3539-060516120522.jpg
Networks http://visionlearning.com/library/modules/mid140/Image/VLObject-3539-060516120522.jpg
Bridging Oxygen http://visionlearning.com/library/modules/mid140/Image/VLObject-3539-060516120522.jpg www.uwgb.edu/dutchs/PETROLGY/NesoSoro.HTM
NBO/T • NBO/T change with melt composition….why? Rhyolite Basalt Mysen, 1983
Structure in Melt Carmichael et al., 1974
Breaking the polymers www.origins.rpi.edu/claycatalyzed.html Carmichael et al., 1974
Polymerization and Viscosity • What will move more easily: • Shorter chain polymers? • 3D networks? • What does that mean w.r.t. rock types?
Viscosity http://video.google.com/videosearch?ndsp=18&um=1&hl=en&client=firefox-a&rls=org.mozilla:en-US:official&q=viscosity&ie=UTF-8& sa=N&tab=iv#ndsp=18&um=1&hl=en&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&q=viscosity&ie=UTF-8&sa=N&tab=iv&start=10
Viscosity, composition, temperature Decreasing SiO2 Scarfe., 1986
Viscosity and pressure Scarfe., 1986
Viscosity and H2O Scarfe., 1986
Lava types and viscosity USGS Ctein
Viscosity regimes Regimes related to temperature w.r.t. Tg T >> Tg Viscosity very low, follows power law: (T) = o(T-Tc)- ~2, Tc = critical T (> Tg) T ~ Tg Intermediate viscosity, follows exponential: (T) = Aeexp(Be/(TSconf)) Ae~0.003, S from experiments, Be from fit T << Tg: Very high viscosity: sample turned into glass (Bottinga et al., 1995)
Rheology and time Webb & Dingwell, 1995