Physical conditions & Bowen’s Reaction SeriesIgneous Rocks & Bowen’s Reaction SeriesPowerPoint PresentationSlide 4Slide 5Slide 6Slide 7Estimating pressure increasesSlide 9Physical conditions & Bowen’s Reaction SeriesPhysical conditions & Bowen’s Reaction Series(Fo then Fa)(Ens then Aug & Di)(An)(Ab)MaficFelsicIgneous Rocks & Bowen’s Reaction SeriesIgneous Rocks & Bowen’s Reaction SeriesMaficFelsicComposition of Igneous RocksComposition of Igneous RocksHeat Sources Heat Sources in the Earthin the Earth1.1. Heat from the early accretion and Heat from the early accretion and differentiation of the Earthdifferentiation of the Earthstill slowly reaching surfacestill slowly reaching surface2.2. Heat released by the radioactive Heat released by the radioactive breakdown of unstable nuclidesbreakdown of unstable nuclidesPreference forPreference formineral phasemineral phasePreferencePreferencefor meltfor meltPlot of ionic radius vs. ionic charge for trace elements of geological interest. Ionic radii are quoted for eight-fold coordination to allow for comparison between elements. From Rollinson(1993).Ionic chargeIonic chargevs. radiusvs. radiusHeat flow and geothermal gradients10°C/km16°/km24°C/kmHeat flow and geothermal gradients10°C/km16°/km24°C/kmBase of crustal root in the Sierra ~30km (=300°C), in the Basin & Range ~20km (=480°C)Estimating Estimating pressure pressure increasesincreasesFigure 1-9. Estimated ranges of oceanic and continental steady-state geotherms to a depth of 100 km using upper and lower limits based on heat flows measured near the surface. After Sclater et al. (1980), Earth. Rev. Geophys. Space Sci., 18, 269-311. Estimate ~3.33 kbar/km(1 GPa = 10 kbar)~6 kb~12 kb€ k = qΔzΔTzTk = q (q)k, thermalconductivityconstant (medium-dependent)To calculate A geothermal gradient from heat
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