Abstract: The inversion of multiple geoscientific datasets to define structures in hard rock terrains has for the most part been limited to geophysical methods supported by rock property constraints. In this paper we expand the range of constraints available to geological modellers by defining a series of misfit functions that are used to define the quality of a given geological model with respect to the available geological data. These misfit functions encompass both spatial and temporal observations, and include primary data such as the location of an outcrop or bore hole location of a given rock type, the orientation of its different generations of foliations, as well as secondary geologic observations such as age relationships. When we combine geologic conditions with geophysical misfit functions, which already exist for many geophysical measures, we have the potential to better constrain two- and 3D models of the Earth. As a first test, a subset of these misfit functions are applied to a set of synthetic three-dimensional volumetric models built with an implicit surface modelling scheme. By perturbing the input structural data within a narrow range, we can simulate a range of significantly different three-dimensional models, for which we can then apply both geological and geophysical misfit functions. Several joint geological/geophysical inversion schemes may be developed based on this methodology, with the ultimate goal being an inversion scheme that simultaneously minimizes both geological and geophysical misfit. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.