Abstract. We propose, test and apply a methodology integrating 1D magnetotelluric (MT) and magnetic data inversion, with a focus on the characterisation of
the cover–basement interface. It consists of a cooperative inversion workflow relying on standalone inversion codes. Probabilistic information about
the presence of rock units is derived from MT and passed on to magnetic inversion through constraints combining structural constraints with
petrophysical prior information. First, we perform the 1D probabilistic inversion of MT data for all sites and recover the respective probabilities
of observing the cover–basement interface, which we interpolate to the rest of the study area. We then calculate the probabilities of observing the
different rock units and partition the model into domains defined by combinations of rock units with non-zero probabilities. Third, we combine these
domains with petrophysical information to apply spatially varying, disjoint interval bound constraints (DIBC) to least-squares magnetic data
inversion using the alternating direction method of multipliers (or ADMM). We demonstrate the proof-of-concept using a realistic synthetic model
reproducing features from the Mansfield area (Victoria, Australia) using a series of uncertainty indicators. We then apply the workflow to field
data from the prospective mining region of Cloncurry (Queensland, Australia). Results indicate that our integration methodology efficiently
leverages the complementarity between separate MT and magnetic data modelling approaches and can improve our capability to image the cover–basement
interface. In the field application case, our findings also suggest that the proposed workflow may be useful to refine existing geological
interpretations and to infer lateral variations within the basement.