C.F. Chung, A.N. Rencz, A. Zhang, D.F. Garson

Contribution to Canada-Alberta Agreement on Mineral Development 1992-1995

As part of the Canada-Alberta Agreement on Mineral Development (1992-1995), several surveys were conducted to produce a geoscientific data base in northeastern Alberta suitable for data integration studies, such as resource assessment. Data from several of these surveys, covering most of 74M, have been released. This work was designed to:

• compile data from a variety of data sources into a common coordinate system
• provide these data in image and digital format
• develop and illustrate a methodology for resource assessment

This open file release meets the first two objectives. Results are presented on the CD-ROM in several formats and are accompanied by software (freeware) for viewing image data.

Data types used in this study and available in this open file are:

• Remotely sensed data:
  • LANDSAT TM
  • ERS-1 (Satellite radar)

• Geophysical data:
  • Radiometric
  • Magnetic

• Geochemical data:
  • Stream waters (35 elements)

• Mineral occurrence data:
  • Location and description of occurrences

• Lithological data:
  • Lithology

Acknowledgments

The authors acknowledge the contributions of: Mike McDonough and colleagues at the Institute of Sedimentary and Petroleum Geology (GSC Calgary, Alberta) (bedrock geology) members of the Radiation Geophysics Section (radiometric, magnetic and gravity data) and the National Geochemical Reconnaissance Program (geochemical data) at the Geological Survey of Canada in Ottawa, the Mineral and Coal Geoscience Section of the Alberta Geological Survey in Edmonton (mineral occurrence data), and the Canada Centre for Remote Sensing, Geomatics Canada (LANDSAT TM and ERS-1 data).

LANDSAT TM data

There are seven bands of LANDSAT TM data. This figure illustrates three colour (red, green, blue) composite of bands 7, 4 and 3. The data were acquired on September 13, 1989.

ERS-1 radar data

The radar data, were acquired on November 7, 1992

The original data have been released as:

This data release includes:

• 7 channels of radiometric data:
  • total count
  • potassium (K)
  • equivalent thorium/potassium (eTh/K)
  • equivalent uranium/potassium (eU/K)
  • equivalent uranium/equivalent thorium (eU/eTh)
  • equivalent thorium (eTh)
  • equivalent uranium (eU)
  • one channel of VLF data
• one channel of magnetic data

Maps of these data produced during this study are:

• ground concentration of potassium (K) (Figure 3)
• eU/eTh (Figure 4)
• eU/K
• eTh/K
• VLF
• magnetic total field (Figure 5)

The data are presented as 8 bit which were derived from the original 16 bit data (32768 levels) for radiometrics and 32 bit real numbers (675316 levels) for magnetics by rescaling between the minimum and maximum values to 1 and 255 respectively. Therefore only 255 possible gray levels are in each channel.

[Click on an image thumbnail to view a larger image, notice]

Ground concentration of potassium (K)

Equivalent uranium/equivalent thorium ratio (eU/eTh)

Magnetic total field

The geochemical data were previously released as:

The data are based on 1160 samples collected in 1993 and include concentration values for 35 elements plus LOI in sediments and uranium, fluoride and pH in waters. Five of the elements were analyzed using two different methods.

From the chemical data for the 634 of these samples which occur in the study area (Figure 6), 42 geochemical images with hydrology overlain were produced. The geochemical sample points were rasterized from Voronoi interpolation using a grid of 30m. The nearest neighbour pixels were assigned the same value as the closest sample point. Sample values below the analytical detection limit were assigned the value 0. The data in the map represent the percentile values, from 1 to 99 with colors displayed from red to blue to represent high concentration to low concentrations respectively. Results for arsenic and copper are shown in Figure 7 and Figure 8 respectively.

The absolute concentration of each element can be derived from a table on the accompanying CD-ROM. In that table, concentrations are provided in ppb and ppm for all elements except: AuWt(g), Fe(pct), LOI(pct), Na(pct) . In addition to the concentration, the table lists analytical methods for each element. The abbreviations for the analytical methods are: AAS (atomic absorption spectrophotometry), INAA (instrumental neutron activation analysis), ISE (ion selective electrode), CV_AAS ( cold vapour / atomic absorption spectrometry), GRAV (gravimetry), GCM (glass Calomel electrode and pH meter) and LIF (laser-induced fluorescence).

[Click on an image thumbnail to view a larger image, notice]

Figure 6: Lake water and lake sediment sample locations

Figure 7: Concentration of arsenic in lake waters and lake sediments

Figure 8: Concentration of copper in lake waters and lake sediments

Mineral occurrences were classified according to the presence or absence of the elements gold, uranium, molybdenum, copper, nickel, lead, zinc, silver, tungsten, chromium and arsenic. For example, in the study area, there are 4 occurrences with copper, 107 with uranium, 36 with gold, 18 with graphite, and 17 with molybdenum. Distribution of occurrences with gold is shown in Figure 9. These data were obtained from:

Monica Price, Wylie Hamilton, and Barry Fildes, Alberta Mineral Deposits and Occurrences, Alberta Geological Survey Open File Report: 91-17, 1991, Mineral and Coal Geoscience Section, Alberta Geological Survey.

Six geologic maps at a scale of 1:50 000 were combined into one coverage (Figure 10) using Arc/Info and rasterized in PCI® EASIPACE™:

Bedrock geology data were derived from the following publications:

Cooley, M.A., McDonough, M.R., Grover, T.W., McNicoll, V.J., Geology, Colin Lake (74M/9), Saskatchewan/Alberta, Geological Survey of Canada, Calgary, Open File 3047, 1994

McDonough, M.R., Grover, T.W., McNicoll, V.J., Cooley, M.A., Schetselaar, E.M., Robinson, N.N., Geology, Cornwall Lake (74M/10), Geological Survey of Canada, Calgary, Open File 2896, 1994

McDonough, M.R., Cooley, M.A., Schetselaar, E.M., Geology, Hay Camp (74M/11), Alberta, Geological Survey of Canada, Calgary, Open File 2832, 1994

McDonough, M.R., Grover, T.W., McNicoll, V.J., Lindsay, D.D., Kelly, K.L., Guerstein, P.G., Geology, Tulip Lake (74M/14), east-half, Alberta-Northwest Territories, Geological Survey of Canada, Calgary, Open File 2820, 1994

Mcdonough, M.R., Grover, T.W., McNicoll, V.J., Lindsay, D.D., Kelly, K.L., Guerstein, P.G., Geology, Mercredi Lake (74M/15), Alberta - Northwest Territories, Geological Survey of Canada, Calgary, Open File 2904, 1994

McDonough, M.R., Grover, T.W., McNicoll, V.J., Lindsay, D.D., Kelly, K.L., Guerstein, P.G., Revised geology, Andrew Lake (74M/16), Alberta -Saskatchewan-Northwest Territories, Geological Survey of Canada, Calgary, Open File 2905, 1994

Each of the input data types was processed as shown in this data processing flow chart. The landsat and ERS-1 data underwent geometric correction. The Geophysical data was scaled to 8-bit. The geochemical data were interpolated and subjected to percentile scaling. The lithology was compiled from a variety of sources. All data layers were reprojected to the projection parameters shown in Table 4.

The image data are provided in two formats. The first is in a PCIDSK format (alberta.pix), created using PCI® software version 5.3.1 and suitable for viewing and processing with PCI® software. The data are contained in 60 channels. The file is 2052 pixels by 3421 lines. The georeferencing information (contained in auxiliary segment 1) is also shown in table 4.

The original data were corrected to a vector file of hydrology using these projection parameters.

The image data are also provided in binary format and have been linearly scaled to 8-bit (0-255). Image size is 2052 pixels by 3421 lines. Sample C and FORTRAN programs are provided on the CD-ROM to illustrate how the user might read the data from the raw image files.

The mineral occurrence data are provided in ASCII-delimited, dBase III® and Microsoft Excel® formats.

The geochemical data are provided in ASCII-fixed-format, dBase III® and Microsoft Excel® 3.0 formats.

The README file on the CD-ROM provides more details on the format of these data and their location on the CD-ROM.