Most kimberlite indicator minerals occur in the 0.25 to 0.5 mm size fraction of non-ferromagnetic heavy mineral concentrates from kimberlite and glacial sediments and can be traced al least 2 km down-ice.

Pyropes have broken along pre-existing fractures as soon as they were released from the kimberlite and picked up by the overriding glacier. Subsequent glacial and glaciofluvial transport of the angular garnet fragments over several kilometers does not reduce their size or change their shape. Therefore, garnet shape and angularity are not conclusive indicators of glacial transport distance.

The relative abundance of pyrope, Cr-diopside, Mg-ilmenite and chromite varies between the four kimberlite pipes. These relative proportions are reflected by indicator minerals abundances in glacial sediments down-ice and can be used to "fingerprint" each pipe. Ilmenite chemistry also can provide a useful fingerprint of a kimberlite pipe.

Till geochemistry reflects the incorporation of kimberlitic bedrock for several elements including, Cr, Ni, Sr, Ba, Ca, Co, Mg, Ta and La in the <0.063 mm fraction, however, the geochemical signature is detectable for only a few 100s m down-ice.

Glacial dispersal of indicator minerals from a kimberlite dyke is detectable only at a very local scale. The heavy mineral signature is diluted within 10 m down-ice and does not contribute to the regional background population.

A 10 kg glacial sediment sample is sufficient weight to detect indicator minerals dispersed from the Kirkland Lake kimberlite pipes. In order to compare results for those samples that are smaller or larger than 10 kg, indicator mineral counts should be normalized to a consistent (10 kg) sample weight.

Acknowledgements

Sudbury Contact Mines Ltd., Regal Goldfields Ltd. and Monopros Ltd. are thanked for providing access to their property, and for sharing samples and confidential geological information. Electron microprobe analysis was completed by J. Stirling and G. Pringle (GSC), by D. Crabtree (Ontario Geological Survey) and by I.M. Kjarsgaard. The Ontario Geological Survey also provided access to the archived glacial sediment samples. The staff of the Ontario Ministry of Northern Development and Mines Drill Core Library, Swastika are thanked for providing logistical support and unlimited access to their facility. D. Schulze, University of Toronto, kindly provided Mg ilmenite data for the C14 and the Diamond Lake pipes.

This project was funded by the Canada-Ontario Subsidiary Agreement on Northern Development (NODA), 1991-1995, under the Canada-Ontario Economic and Regional Development Agreement.