Properties of oceanic lithosphere: Revised plate cooling model predictions

A new analysis of plate cooling models indicates that the properties of oceanic lithosphere may need to be reevaluated, or that additional phenomena beyond the conditions of simple mineral physics plate models are important. Thermal models with constant and variable mineral physics properties are formally analyzed for fits against recently filtered databases for heat flow and topography. Formalisms are developed for the evaluation of the effective properties of oceanic lithosphere and the treatment of temperature-dependent thermal conductivity and thermal expansivity as both variable and freely adjustable parameters in fitting analysis. Excellent fits to depth and heat flow are resolved for a wide range of models. Good fitting parameterizations reproduce conventional estimates of net surface heat flux (∼31.5±1.0 TW) while the apparent thermal diffusivity is higher (∼1.1±0.1 mm2 s−1) and apparent thermal expansivity is lower (∼2.4×10−5 K−1) than previous reference models. Two preferred reference models, R1 and RT1, are resolved, which are consistent with evidence of mantle temperature and plate thickness, and do not require adjustments to experimental heat transport properties.

► A new analysis with variable properties and updated geophysical constraints. ► Thermal properties explored as both temperature-dependent and free parameters. ► Formalisms developed for the analysis of variable thermal properties. ► Excellent fits to geophysical observations resolved. ► Best fits predict high thermal diffusivity and low thermal expansivity.