1. A method of processing geophysical data including at least measured potential field data from a potential field survey of a surveyed region of the earth to provide a representation of the geology of said surveyed region, the method comprising: generating a first model of said surveyed region by fitting data predicted by said first model to said measured data for a specified frequency range; predicting full range potential field data for all measured frequencies using said generated first model; comparing said full range predicted data to said measured potential field data to provide full range residual data representing a difference between the full range predicted data and the full range measured data, and interpreting said full range residual data to provide a representation of said geology of said surveyed region.