Temperature dependence of the polarized electronic absorption spectra of olivines. Part I - fayalite

Critical phenomena in thermal conductivity: Implications for lower mantle dynamics

“…Peak area generally increases with T (Taran and Langer, 2001;Ullrich et al, 2002). If dA is small, A increasing with T strengthens the temperature dependence of k rad at all T (Eq.…”

“…The type of rheological behavior largely dictates the dynamical regimes in mantle convection (e.g. van den Berg and Yuen, 1996). To visualize the effect of thresholds in k on geodynamic models, we map mechanisms for mantle heat transfer onto a domain diagram which considers the effects of T, P and grain-size (Fig.…”

“…Yuen et al, 2000). The inferred behavior is complex and counterintuitive (van den Berg et al, 2001). Specifically, k rad increasing with T controls the time dependence and stabilizes planforms of mantle convection through positive feedback, whereas k lat decreasing with T is destabilizing, making convection more chaotic and time-dependent (Dubuffet et al, 2002;Yanagawa et al, 2005).…”

Ultraviolet spectral reflectance properties of common planetary minerals

“…Calculated energies of the highest wavelength Fe-O charge transfer transitions for Fe in octahedral coordination are 267 nm (37,500 cm −1 ) for Fe 2+ versus 395 nm (29,400 cm −1 ) for Fe 3+ . The Fe 3+ -O charge transfer is particularly intense and can be present in olivine spectra, even though Fe 3+ /Fe 2+ ratios of olivine are very low (Ullrich et al, 2002).…”

Dependence of diffusive radiative transfer on grain-size, temperature, and Fe-content: Implications for mantle processes

“…Section 3 reports new IR spectra on olivine at elevated temperature, and combines these data with recent measurements of visible spectra at high T (Taran and Langer, 2001;Ullrich et al, 2002) for use in the model. Section 4 quantifies the complex dependence of k rad,dif on T, d, and Fe 2+ concentration.…”