The Late Cretaceous (Coniacian) Bad Heart Formation is a unique ooidal ironstone deposit in Western Canada. It is estimated to contain 1.1 billion tonnes of ore containing 34% iron. In 2004, Alberta Geological Survey (AGS) started extensive mapping and geochemical sampling in that area to re-evaluate its potential and to generate interest among industry for further exploration work.
During this study, AGS staff members did detailed section mapping of all available outcrops and excavated trenches, and collected geochemical and palynological samples. In total, we collected 325 rock samples for geochemistry and 197 samples for palynological study. The interpretations of these determined the stratigraphic relationship of ooidal ironstone between the Smoky River and Clear Hills regions and determined the relative age of strata below and above the ooidal ironstone.
The maximum thickness of ooidal ironstone is about 10 m along Rambling River and up to 4 m thick along the Smoky River. The major prospective area for thicker ooidal ironstone is around Rambling River and in the subcrop beneath the bogs and glacial drift south of Highway 49 and east of Birch Hills. Besides iron, zinc (average 575 ppm and maximum 1040 ppm) and vanadium (average 1300 ppm and up to 2598 ppm) have elevated concentrations in the ooidal ironstone and may be considered as potential co-products. Previous studies have documented elevated concentrations of gold in the ooidal ironstone; however, samples from this study yielded no gold values higher than 3.4 ppb.
See associated Digital Dataset 2009-01 for the geochemical analyses results.
Kafle, B. (2008): Geochemistry and preliminary stratigraphy of ooidal ironstone of the Bad Heart Formation, Clear Hills and Smoky River regions, northwestern Alberta; Energy Resources Conservation Board, ERCB/AGS Open File Report 2009-01, 97 p.