Radiometric data
Authors: Ford K L 
Published: March 2017

Ground Gamma Ray Spectrometry (GGRS): Results from 863 ground gamma ray spectrometry measurements are provided in GGRS.xls along with positional information as decimal degrees and as UTM coordinates (NAD 83). Potassium (K, pct), equivalent uranium (eU, ppm) and
equivalent thorium (eTh, ppm) concentrations were determined using a portable gamma ray spectrometer (Exploranium Model GR-320 with a 3"x3" (21 in3) NaI detector). Uranium and thorium concentrations determined by gamma ray spectrometry use the term "equivalent" or its abbreviation "e" to indicate
that equilibrium is assumed between the radioactive daughter isotope monitored by the spectrometer and its respective parent isotope. Uranium238 is estimated by measuring one of its daughter isotopes, bismuth214 and thorium232 is estimated by measuring thallium208. Potassium is measured directly, as
K40, thus "equivalent" is not applicable. Columns RUT, RUK and RTK are radioactive element ratios calculated from the measured K, eU and eTh concentrations. Total count scintillometer (Scint) and magnetic susceptibility (MS) values are also recorded. At a few locations total count scintillometer and
magnetic susceptibility values were not recorded. These are recorded as blank in the spreadsheet and as -9999 in the dbf file attached to the appropriate shape file. Each measurement location is initially scanned with an Exploranium GRS-101A total count scintillometer to determine the normal range
of total radioactivity and to delineate isolated high or low radioactivity zones. Map Code and Rock Type or Formations were derived from GSC Open Files 4199, 4200, 4433 and 4474. Sheet "AllGGRS" provides results from all 863 spectrometer measurements. Often multiple spectrometer measurements would
be made at one GPS location, usually within +/- 10 metres of the other measurements. If rock types are the same these multiple measurements were averaged and these results presented in sheet "AllAve" with an extra column (#Stns) to indicate the number of measurements that were averaged. Sheet
"Stats" provides a number of statistical calculations to describe the radioactive element signatures for each of the major lithologies. Following the text portion of this document histograms of the Potassium (pct), eUranium (ppm) and eThorium (ppm) concentrations for the three most measured
non-Piling Group units (Agr, Agn and Pgr) are provided. At a small number of locations field observations indicated that the unit designation was inconclusive. These are indicated by a (?) in the spreadsheet and by hatching on the histograms for units Agr and Agn. For unit Pgr, pegmatitic (peg) and
non-pegmatitic varieties are distinquished. In addition to the histograms, graphs of eThorium (ppm) vs Potassium (pct), eUranium (ppm) vs eThorium (ppm) and eUranium (ppm) vs Potassium (pct) for all non-Piling Group and Piling Group measurements are also provided.
Results of laboratory gamma ray spectrometry analysis for 722 till samples collected by Dr. L. Dredge (GSC) are provided in TillGRS.xls along with positional information as decimal degrees and as UTM coordinates (NAD 83). The sand fraction (0.063 - 2 mm) that was separated from the silt and clay
fractions by dry sieving was used for the LGRS analysis. Sample weights ranged between 237g and 499g. In addition to the results of the LGRS analysis (K, eU and eTh), K by ICP-AES and U and Th by INAA analysis were also provided by Dr. L. Dredge and are included. A number of statistical calculations
to describe the radioactive element signatures of these till samples are included. Following the text portion of this document histograms of the potassium, uranium and thorium concentrations and the eU/eTh, eU/K and eTh/K ratios in the greater than 0.063mm size fraction of the till samples as
determined by LGRS analysis are provided. These are followed by histograms of the potassium concentrations in the less than 0.002mm size fraction as determined by ICP-AES analysis and uranium and thorium concentrations in the less than 0.063mm size fraction as determined by INAA
analysis.