A gravity survey over the Aulneau batholith, northwestern Ontario, shows that the batholith is expressed as a gravity low of approximately 40 mGal relative to the level of the gravity field over neighbouring greenstone rocks. Assuming that surface density contrasts extend to depth, then three-dimensional modelling of the gravity data indicates that the floor of the batholith, in general, is located between depths of 4.5–7 km. Locally, in two regions, prominent plugs extend to 11–12 km depth. The modelling also suggests that the wall contacts of the batholith are generally steep and inward dipping, a picture supported by earlier seismic studies.

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