|
Details: Iron Mask Geophysics covers the 1995 Iron Mask survey represented in Geological Survey of Canada Open File 2817. This survey was published to MapPlace on April 8, 2005. The MapPlace data includes digital gridded images for 2 magnetic and 7 radiometric parameters for each survey area. The downloadable files from this website are in georeferenced TIF – tagged image and PNG formats (UTM NAD 83 and Albers projections) and GRD - Geosoft gridded data format (UTM NAD 83 only). PDF theme files, which represents a subset of the geophysical data, available in Open File 2006-12: Integrated Airborne Geophysical, Geology and Mineral Occurrence Data, Iron Mask Batholith. Geology of the Iron Mask Batholith is available as Open File Map 2006-11.
See GeoFile 2006-5 for a review of the regional geological setting, tectonics, geochronology, geophysics, mineralization and alteration characteristics of the Iron Mask Batholith.
View Iron Mask Geophysics Map
Survey Summary:
IRON MASK GEOPHYSICAL SURVEY
BCMEM Open File 2005-13 / GSC Open File 2817
Airborne geophysical survey, Iron Mask Batholith, British Columbia
(Parts of NTS 92I/08NW; 92I/09SW; 92I/10; 92I/15SE)
by Shives, R.B.K.; Carson, J.M., Geological Survey of Canada; 61 pages, 18 maps
Analogue and digital products include data for seven radiometric and two magnetic parameters:
| Map Layer Themes |
Iron Mask
PDF Themes Files |
| MTF - Magnetic total field (nT) |
See Open File 2006-12:
Integrated Airborne Geophysical, Geology and Mineral Occurrence Data, Iron Mask Batholith. |
| CVG - Calculated magnetic vertical gradient (computed, nT/m) |
| POT - Potassium (K, %) |
| URA - equivalent Uranium (eU, ppm) |
| THO - equivalent Thorium (eTh, ppm) |
| ADRN - Natural air absorbed dose rate (ADRN, nGy/h) |
| RUT - equivalent Uranium/equivalent Thorium (eU/eTh) |
| RUK - equivalent Uranium/Potassium (eU/K, ppm/%) |
| RTK - equivalent Thorium/Potassium (eTh/K, ppm/%) |
| 1:250K Scale Geology, Mineral Occurrences & Titles |
| All Themes in one file (11 by 17 images) |
| File Downloads |
Zip Files
see Note 1 |
| Georeferenced TIFF files (UTM Zone 10 NAD 83) |
I_tif_Z10.zip (3.6MB) |
| Georeferenced TIFF files (Albers NAD 83) |
I_tif_AL.zip (3.6MB) |
| Georeferenced PNG files (UTM Zone 10 NAD 83) |
I_png_Z10.zip (1.8MB) |
| Georeferenced PNG files (Albers NAD 83) |
I_png_AL.zip (1.9MB) |
| Original GSC SurView data files for viewing and printing only (.gri & .grx) |
I_gri.zip (10.9MB) |
| Original GSC Geosoft gridded data format (.grd), see Note 2 |
I_grid.zip (12.5MB) |
Note 1: The TIF and PNG download images include the geophysical information without topographic base information.
|
Legend:
K - potassium, i.e. K40 (units: %)
eU - equivalent uranium concentration by weight (the spectrometer directly measures Bi214, that is an indirect measure of uranium) (units: ppm)
eTh - equivalent thorium concentration by weight (the spectrometer directly measures Tl208, that is an indirect measure of thorium) (units: ppm)
Total Count - all counts from 400 to 3000 keV. (units: cps or uR/h)
Natural Exposure - computed from K (%), eU (ppm), eTh (ppm) concentrations:
Exposure = 1.505 K + 0.625 eU + 0.31 eTh (uR/h)
(Grasty et al, 1984) 'Exposure' is different from the traditional 'Total Count', in that it excludes radiation from man-made contaminants.
Natural Air Absorbed Dose Rate - computed from K (%), eU (ppm), eTh (ppm) concentrations:
Absorbed Dose Rate = 13.08 K + 5.43 eU + 2.69 eTh (nGy/h) 'Natural Air Absorbed Dose Rate' is different from the traditional 'Total Count', in that it excludes radiation from man-made contaminants.
eU/eTh, eU/K, eTh/K - ratios of K, eU, eTh that are useful for interpretation |
Units:
nT - unit of magnetic total field (nano Tesla)
ppm - unit of concentration by weight (part per million), used for eU (uranium) and eTh (thorium)
% - for potassium (K40): unit of concentration by weight
Ur - unit of radioelement concentration by weight
(1 Ur is defined as the total count rate from 1 ppm uranium in equilibrium)
µR/h - unit of Exposure (micro Roentgen/hour)
nGy/h - unit of Natural Air Absorbed Dose Rate (nano Gray/hour) | |
