Till Geochemistry in the Sawn Lake Area, Southern Buffalo Head Hills, Alberta (NTS 84B/13)

This report presents geochemical results for the <63 µm fraction of 67 till samples and 1 glaciofluvial sand sample from the Sawn Lake map area. Fifty-four of the till samples and the glaciofluvial sample were collected in 2002. Twelve till samples discussed in this report were collected before 2002 and analyzed (reanalyzed) along with the 2002 samples. Kimberlite-indicator mineral (KIM) data from these samples were released previously.

Tills of the Sawn Lake area typically contain about 40% clay, 30% silt and 30% sand. Intriguing compositional differences exist between ablation till (ice-stagnation deposits) and non-ablation till (which includes basal till). On average, the ablation till has higher MgO, CaO, calcite and dolomite values, whereas the non-ablation till has higher Mo, U, Sb and Se values. These differences may reflect a higher component of Cretaceous shale, particularly organic-rich shale, in the basal till component of the non-ablation till compared to a somewhat greater amount of limestone and dolomite debris, derived from distant Paleozoic strata, in the ablation till.