How to assess similarities and differences between mantle circulation models and Earth using disparate independent observations

Mantle circulation in the Earth acts to remove heat from its interior and is thus a critical driver of our planet’s internal and surface evolution. Numerical mantle circulation models (MCMs) driven by plate motion history allow us to model relevant physical and chemical processes and help answer questions related to mantle properties and circulation. Predictions from MCMs can be tested using a variety of observations. Here, we illustrate how the combination of many disparate observations leads to constraints on mantle circulation across space and time. We present this approach by first describing the set-up of the example test MCM, including the parameterization of melting, and the methodology used to obtain elastic Earth models. We subsequently describe different constraints, that either provide information about present-day mantle (e.g. seismic velocity structure and surface deflection) or its temporal evolution (e.g. geomagnetic reversal frequency, geochemical isotope ratios and temperature of upper mantle sampled by lavas). We illustrate the information that each observation provides by applying it to a single MCM. In future work, we shall apply these observational constraints to a large number of MCMs, which will allow us to address questions related to Earth-like mantle circulation.