Joint inversions of two VTEM surveys using quasi-3D TDEM and 3D magnetic inversion algorithms

Abstract

In the current paper, we present results of a joint quasi-three-dimensional (quasi-3D) inversion of two versatile time domain electromagnetic (VTEM) datasets, as well as a joint 3D inversion of associated aeromagnetic datasets, from two surveys flown six years apart from one another (2007 and 2013) over a volcanogenic massive sulphide gold (VMS-Au) prospect in northern Ontario, Canada. The time domain electromagnetic (TDEM) data were inverted jointly using the spatially constrained inversion (SCI) approach. In order to increase the coherency in the model space, a calibration parameter was added. This was followed by a joint inversion of the total magnetic intensity (TMI) data extracted from the two surveys. The results of the inversions have been studied and matched with the known geology, adding some new valuable information to the ongoing mineral exploration initiative.

We present the results of a joint quasi-3D inversion of two VTEM datasets, flown over a VMS-Au prospect in northern Ontario, Canada, six years apart from one another. The TDEM data were inverted jointly using the spatially constrained inversion (SCI) approach and verified against known geology.

Key words::

• airborne EM, inversion, magnetics, TDEM, VMS.

Acknowledgements

The authors would like to thank Promiseland Exploration Ltd for providing the VTEM data, as well as Geotech Ltd for their contribution to better understanding of VTEM data and for their input in assessing the results of inversions.