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Surface seismic profiling is well suited for geologic provinces characterized by low to moderate dip, but it is less effective where dips exceed 65 degrees due to inherent limitations of the recording geometry and processing algorithms. Vertical seismic profiling (VSP), a method used mainly for hydrocarbon exploration in sedimentary basins, overcomes this limitation by utilizing deep boreholes as an alternative acquisition datum. Here, we evaluate the effectiveness of this method for imaging massive sulfide deposits associated with folded and steeply dipping volcanic units near the Kidd Creek orebody in Ontario, Canada. Small (150-225 g) explosive charges placed in a water-filled pit provided a consistent energy source, with sufficient band width and signal penetration to image the target zone to a depth of at least 1.0 km. After preliminary processing, the vertical seismic profile record sections were mapped into cross sectional format using a transformation based on ray tracing. This transformation facilitates the extrapolation of subsurface contacts updip from borehole intersections, and the resulting images delineate several stratigraphic contacts in addition to a prominent seismic reflection from a massive sulfide body.

Conventional seismic methods are generally not effective for imaging geological structures with very steep dips, a common situation in some mining camps. Deep boreholes provide an alternative acquisition datum for seismic imaging in this type of setting. At the giant Kidd Creek CuZn deposit, the Archean volcanic stratigraphy has been folded and overturned so that most units are nearly vertical. Borehole logging and laboratory measurements conducted here show that certain stratigraphic contacts, especially those where massive-sulphide deposits and felsic host rocks are juxtaposed, are characterized by large impedance contrasts and are thus good candidates as seismic reflectors. To investigate this possiblity, a series of borehole-seismic profiling experiments were conducted in an area of known sulphide mineralization. Several source configurations were used, yielding both vertical and horizontal seismic images of the volcanic stratigraphy. In addition to observing reflections that correlate with stratigraphic contacts, prominent seismic anomalies were detected and have been correlated with a known massive-sulphide deposit.