Preliminary Report on the Gravel Resources of the Red Deer Area - Explanatory Notes

For the purpose of this report a radius of approximately 25 miles of the City of Red Deer was chosen for study. In terms of the encompassing townships the area may be described as lying between range 23 west of the fourth meridian and range 3 west of the fifth meridian and between townships 34 and 42. An area of approximately 3000 square miles is thus included. The major parts of the counties of Red Deer and Lacombe fall within the study region.

The bedrock underlying the entire area belongs to the non-marine Tertiary and Upper Cretaceous Paskapoo Formation which is comprised of grey to greenish grey, thick-bedded, calcareous, cherty sandstone; grey and green mudstone; minor carbonate, thin limestone, coal and tuff beds (Green, 1972). The overlying surficial deposits of nearly the entire area have been mapped by Stalker (1956, 1960) and Bayrock, Boydell and Reimchen (in preparation). A reconnaissance mapping of the southwest portion was carried out by the writer. A simplified composite map of the surficial geology is presented in figure 2.

Investigations for gravel during the summer of 1973 were confined to areas blanketed by preglacial alluvial deposits, glacial outwash, deltaic alluvial deposit, and recent alluvium as outlined in figures 3, 4, 5 and 6. Surrounding deposits include tills, lacustrine materials and sand dunes which yield little or no coarse graded sediments. Topographic base maps with a scale of 1:50 000 were employed for surface control. Air photos were scanned to provide further interpretation with respect to the areal extent of deposits and location of pits and exposures. Prospective area were visited and bulk sampled. Western Canadian Geological Drilling Services were retained to supplement surface information and as a result approximately 200 auger holes were drilled with a truck-mounted 8 inch auger at regular intervals within promising areas. Drilling was commonly confined to depths of less than 25 feet and sites were only selected along road allowances. Satisfactory samples were obtained from drilling although few materials greater than 3 inches in diameter were recovered. Test hole data from records in the files of the Groundwater Division were used in addition to drilling information from the 1973 program.

Location of pits, exposures and test holes are given in figures 3 to 6 inclusive. The depth of gravel in each occurrence is indicated wherever the thickness exceeds 5 feet. Sample numbers of each are given and the pertinent analyses may be referred to in tables 1 and 2 and the appendix of this report.

Coal analyses were run on the minus #8 sieve fraction of pit and exposure samples according to the Alberta Department of Highways laboratory procedures.

Sieve analyses were run on all samples and deviate from ASTM and Alberta Department of Highways procedures only in the use of a slightly different nest of coarse sieves.

Pebble counts were run on the minus 1 1/2' and plus 5/8' fraction of pit and exposure samples. Quartzite pebbles were counted independently of metamorphics, the latter of which normally consist of gneisses. The chart typically shows very little indication of erosional deterioration and, although some workers discourage the use of chert-bearing gravels (e.g., Price, 1958), there appears to be little concern for its effects in regular usage. The sandstones vary considerably from soft Paskapoo-derived rock to well cemented Lower Cretaceous materials. Deposits which contain high percentages of igneous and metamorphic rock are of good quality except in areas where weathering conditions have resulted in friable pebbles. Vein quartz was arbitrarily counted with igneous pebbles. Shales and ironstones are normally considered detrimental materials.