New Constraints on the Thermal Conductivity of the Upper Mantle From Numerical Models of Radiation Transport

摘要: To address uncertainties in the values and mathematical form of radiative thermal conductivity k_(rad) mantle, we developed new models for transport, scattering, absorption radiation semitransparent multiphase polycrystalline assemblages. We show that Rosseland diffusion equation correctly describes infer effective spectral coefficients through numerical experimentation. scattering coefficient depends on grain size interphase contact statistics complicated ways, but simplifications can be employed practice. The opacity a composite random material is harmonically weighted mixture limit infinitely large an arithmetically infinitesimal size. Using existing spectra major upper mantle minerals, estimate as function temperature, size, petrology. In assemblages, effect important small sizes (<1 mm), medium up to 10 cm. calculate about 2–3.5 W·m^(−1)·K^(−1) representative mean range 0.01 1 This translates total 5.5–7 W·m^(−1)·K^(−1). Application our model cooling oceanic lithosphere shows increases net by 25%.