Open File Report 1995-12

Author(s) Date 1995-11-22

The overall objectives of this reconnaissance project, which is partially funded under the Canada-Alberta Partnership Agreement on Mineral Development (MDA), are to determine the regional variations in the compositions (geochemistry, mineralogy, and texture) and the provenance of the tills in northern Alberta in order to assist exploration by industry for diamondiferous kimberlites or lamproites, gold placers, and other minerals of potential of economic interest. This is the interim report for Phase 3 (1994-95) of a three year project and focuses on northeastern Alberta (north of 55° N and east of 115° W). The report is relatively brief because it will be superseded by the final project report which is in preparation for publication in the last quarter of 1997-98.

Ninety-five samples, which were collected for a suite of elements from both road and helicopter accessible sites, were analysed. The clay and silt fraction (<0.063 mm) was analysed using Flame Atomic Absorption Spectrophotometry (AA, following total sample digestion) and Instrumental Neutron Activation Analysis (NA) techniques. The collection and analytical procedures and the chemical elements being measured are the same as those selected by Drs. Garrett and Thorleifson for the complementary Geological Survey of Canada MDA project on till mineralogy and geochemistry in the southern half of Alberta.

This report discusses twenty-four elements: silver (Ag), arsenic (As), gold (Au), barium (Ba), bromine (Br), cadmium (Cd), cobalt (Co), chronium (Cr), copper (Cu), iron (Fe), lithium (Li), manganese (Mn), molybdenum (Mo), sodium (Na), nickel (Ni), lead (Pb), rubidium (Rb), antimony (Sb), thorium (Th), uranium (U), vanadium (V), tungsten (W), zinc (Zn), and zirconium (Zr).

Variations in the data are illustrated by a figure shows the concentration range for each element in histogram format, and a series of bubble plot maps. Each plot is underlain by the bedrock geology to help show the influence of the bedrock on the till geochemistry.

The concentration of almost all the elements varies considerably throughout the study area. Many of the elements show high concentration in samples from sites that are above or below glacier, the subcrop of the Shaftesbury Formation, particularly those samples from the northeast portion of the Buffalo Head Hills and the northwest and northeast portion of the Birch Mountains. The three sites having the highest concentrations of Co, Cr, Li, Zn, Sb, V and Zn are located along an imaginary line that passes through the northeast corner of the Buffalo Head Hills, and the northern margin of the Birch Mountains. This may just be a coincidence or it may indicate a possible structural control.

Geological sections which are exposed along the Firebag River, east of the Athabasca River, show multiple till units. Data from a section with three till units on the Firebag River reveal vertical variation in the geochemistry with depth; some elements decrease in concentration, others increase, and some are concentrated in the middle till unit.

Place Keywords

Fenton, M.M. and Pawlowicz, J.G. (1997): Reconnaissance mineral and geochemical survey with emphasis on northern Alberta, report for the end fiscal year 1994-1995, till geochemistry northeastern Alberta; Alberta Energy and Utilities Board, EUB/AGS Open File Report 1995-12, 69 p.