Survey Metadata

In 1971, 176 samples of inorganic lake sediments were collected from eight areas within the Bear and Slave geological provinces in Nunavut and Northwest Territories as part of a pilot study to test geochemical methods for large scale reconnaissance surveys of the Canadian Shield.  To relate the chemistry of the lake sediments to surrounding bedrock, 447 rock samples of various types were also collected from five of the eight areas.

The main field operation (Operation Bear-Slave) was carried out from June 25th to August 2nd, 1972 in an area between Great Slave and Great Bear lakes, a region covering approximately 36,000 square miles of the Canadian Shield.  Near-shore lake sediment and surface lake water samples were collected at a density of 1 sample every 10 square miles.  A total of 4,104 sites were sampled.

In 1973, follow-up studies were carried out in the eastern part of the Slave province.  The first stage of the follow-up involved resampling lake sediments from a 1500 square mile area.  The lakes were different from those sampled in 1972.  The second stage involved detailed studies of certain anomalies from the 1972 sampling.  Within these detailed areas (Agricola, Sanctuary, Ferric and Casey lakes – provisional names) rock and soil samples were collected in addition to lake sediments.

The following Geological Survey of Canada reports have been published:

 

Year of Field Work	Description	GSC Publication
1971	summary of pilot studies; some small element distribution maps	Open File 89
1972	content in lake sediments of selected elements	Preliminary Maps 9-1972 to 15-1972
1972	sample locations	Preliminary Map 16-1972
1972	summary of the work	Paper 72-50
1972	digital release of entire data set	Open File 2239
1973	follow-up studies	Paper 74-27 Open File 175 Paper 74-1A

 

Following the discovery of diamonds at Lac de Gras, samples from 217 sites from NTS sheets 76B (NW quadrant) and 76D (NE quadrant) were re-analysed by INAA.  The results are published in Geological Survey of Canada Open File 2578.

A more detailed summary of the sampling and analytical history is available as a separate PDF document, along with an MS Excel file listing all of the samples collected in 1972.

The lake sediment samples came from near the shore, near islands or above reefs at water depths of 3 to 8 feet.  Samples were taken using a 6-foot-long post-hole soil auger.  Two water samples were collected from beneath the lake surface at each sediment site by leaning out of the helicopter while it was being held steady on the lake surface.