LETTERS TO THE EDITOR — Studies by GSC support presence of

I wish to clarify statements published in The Northern Miner regarding Geological Survey of Canada (GSC) research on gold and associated mineralization in the Fort MacKay region of northeastern Alberta (“GSC studies gold, PGE anomalies in Alberta,” April 18/94).

The article states that results presented by myself and post-doctoral researcher Rui Feng show a systematic discrepancy between solution and laser ablation (LA) Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) because of “an analytical problem.”

As noted in the information provided to The Northern Miner, the solution ICP-MS results were preliminary and the differences observed between the two methods most likely reflected incomplete extraction of gold into solution, not the type of instrumental analysis.

Nevertheless, our conclusions still stand: “. . . anomalous gold concentrations do exist in Upper Devonian carbonates and Mesozoic clastic rocks in the Fort MacKay area of northeastern Alberta.”

Direct analysis by LA-ICP-MS has been shown to be capable of reproducibly detecting gold in these rocks and further work has documented gold and polymetallic mineralization in a variety of lithologies in the Fort MacKay area.

Confirmation of the presence of gold in these rocks by direct microanalysis and observation challenges standard assaying procedures, which report little or no gold.

It is my belief that the Canadian assaying community can rise to this challenge by developing methods for analysis of this previously “unassayable” gold mineralization.

H.J. Abercrombie

Geological Survey of Canada

Calgary, Alta.