With the exception of mantle xenoliths and limited exposures of mantle rocks in collisional orogenic belts, the continental lithospheric mantle is generally inaccessible to direct observation. Knowledge of parameters such as the age, thickness and internal geometry of the upper mantle, all of which could be used to optimize exploration strategies for kimberlites or lamproites likely to have originated in the diamond stability field, may only be available indirectly through geophysical techniques. A new generation of teleseismic and deep-probing electromagnetic methods have emerged recently, that provide passive and cost-effective means to infer this information and to map the lithospheric mantle in its entirety, from the base of the crust to the asthenosphere.
This paper provides a brief overview of these techniques, and describes ongoing experiments that comprise part of Lithoprobe, Canada's national collaborative geoscience program involving the GSC and NSERC. Other non-Lithoprobe experiments have been proposed as well, and if funded will contribute further to our knowledge of the Canadian lithosphere. The objective of this paper is to provide a brief outline of the relevant techniques; more detailed discussions of the various methods may be found in the references cited in each section.
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