Earth Sciences Report 2001-20

Earth Sciences Report 2001-20

ESR 2001-20

Alberta Kimberlite-Indicator Mineral Geochemical Compilation

Since the initial discovery of a kimberlitic diatreme in northern Alberta, government and exploration companies have collected a plethora of bedrock, till and stream-sediment heavy-mineral concentrate (HMC) samples throughout Alberta. Subsequently, kimberlite- or diamond indicator minerals (KIM), which include garnet, chrome diopside, ilmenite and chromite, have been analyzed by electron microprobe to determine their geochemical properties used to provide some basis for prioritizing exploration targets. Table 1 summarizes some standard geochemical criteria used by exploration companies in search for diamondiferous kimberlite.

The Alberta Geological Survey (AGS) is the current custodian of Mineral Assessment Reports, which may contain the geochemical data reported by industry under regulatory conditions outlined by the Alberta Department of Resource Development. These geochemical data have been scanned into electronic format and were compiled with existing government microprobe data. In addition, numerous companies contributed non-assessment report KIM data to this study and we thank these companies for their invaluable contribution to further our understanding of Alberta geology.

This compilation is the first known update of Alberta KIM's since the 1996 AGS Bulletin 63 (The Diamond Potential of Alberta), which produced a diamond indicator mineral summary map based on the geochemistry from about 560 grains. The current KIM database is comprised of more than 20,000 geochemical analyses.

The results of the compilation are delivered in this CD-ROM with an interactive menu that allows the user to access:

1) the digital geochemical data in portable document format (PDF), Microsoft(r) Excel spreadsheets, or comma-delimited text files; the files are categorized by KIM grain-type (I.e., garnet, clinopyroxene, ilmenite, and chromite);

2) an updated KIM anomaly summary map of Alberta;

3) provincial scale maps with favourable KIM areas by grain type; and

4) a variety of scatter plots that show geochemical trends and variations across the province.

This compilation is intended to release the geochemical microprobe data from industry and government KIM studies, which are available to the public. To date, no attempt has been made at including the methodologies of the original survey, such as sample media and procedures, laboratory names, laboratory techniques, laboratory standards, and duplicates. This information may or may not be reported in the assessment report. Individuals may view mineral assessment reports at the AGS for complete survey details. The reports are also available for purchase from the Alberta Geological Survey Information Sales office.

Eccles, D.R., Dufresne, M.B., Copeland, D.A., Csanyi, W. and Creighton, S. (2002): Alberta kimberlite-indicator mineral geochemical compilation; Alberta Energy and Utilities Board, EUB/AGS Earth Sciences Report 2001-20, 8 p.