Thermochemical structure of the lithosphere and upper mantle beneath Superior craton: Results from multi-observable probabilistic inversion

We present new thermochemical models of the lithosphere and upper mantle beneath the Superior craton and surrounding regions. The study area is dominated by the Archean Superior Province, surrounded by Proterozoic orogenic belts such as the Trans-Hudson Orogen (THO) to the north and the Grenville Orogen to the southeast. Portions of the Rae and Hearne cratons north of the THO are also studied, as is the Mid-continent Rift to the south. Over a period of ∼3 Ga, the region has seen assembly and modification by accretionary and orogenic events, periods of rifting, and the influence of a number of mantle hotspots. Here, we use a probabilistic inverse method to jointly invert Rayleigh wave dispersion data, Vp data, geoid anomalies, surface heat flow, and absolute elevation. The output is a 3D model of the seismic, temperature, bulk density, and compositional structure of the whole lithosphere beneath the Superior craton.

The resulting model will provide new opportunities for joint studies of the structure of the upper mantle and will shed light on the thermal and compositional variations beneath the region. In this presentation, we will discuss the results from our model and several robust features that carry important geological and geodynamical implications for this region.