melt properties
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
Melt Properties
Updates/questions?
• Labs:• Field trip:18th or 19th?
• Last lecture’s 3 remaining slides in lab
Today’s topics:1. Magma properties
Melt properties - Internal variables
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
www.uwgb.edu/dutchs/PETROLGY/NesoSoro.HTM
http://visionlearning.com/library/modules/mid140/Image/VLObject-3539-060516120522.jpg
NBO/T•NBO/T change with melt composition….why?
Mysen, 1983
Rhyolite Basalt
Structure in Melt
Carmichael et al., 1974
Breaking the polymers
Carmichael et al., 1974
www.origins.rpi.edu/claycatalyzed.html
Effect of volatiles
Polymerization and Viscosity
• What will move more easily:
a) Shorter chain polymers?
b) 3D networks?
• What does that mean w.r.t. rock types?
Viscosity
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
Viscosity, composition, temperature
Scarfe., 1986
Decreasing SiO2
Viscosity and pressure
Scarfe., 1986
Viscosity and H2O
Scarfe., 1986
Lava types and viscosityUSGS
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
Glass Transition