During December 2004, the Geological Survey of Canada and Alberta Geological Survey drilled a stratigraphic study hole in the Buffalo Head Hills kimberlite field, north-central Alberta, to obtain uppermost Upper Cretaceous and early Paleocene sedimentary cores.
The primary objective for drilling the study drillhole was to obtain rocks that were previously inaccessible because the area is covered by surficial deposits of variable thickness, and oil and gas wells typically case through the Cretaceous stratigraphy. A second objective was to core a sedimentary rock section adjacent to a known kimberlite body to study sedimentary rock characteristics in a ‘proximal’ kimberlite setting.
A third objective was to log the drillhole by borehole natural gamma-ray (ɣ-ray) measurements intended to assist with mapping relatively unknown strata, and to enable comparison with wire-line logs from oil and gas wells in the area.
A comparison between geochemical data, petrographic interpretation and downhole spectral ɣ-ray anomalies shows that the downhole spectral ɣ-ray anomalies can be used to identify potential horizons influenced by kimberlitic- and metallic mineral-bearing fluids and rock types.
Given the many oil and gas well logs available for viewing, further investigation of downhole spectral ɣ-ray surveys is warranted.
Eccles, D.R. (2009): Geochemical and petrographic evaluation of downhole gamma-ray anomalies in the Buffalo Head Hills kimberlite field, north-central Alberta (NTS 84B/13); Energy Resources Conservation Board, ERCB/AGS Open File Report 2009-03, 23 p.