Poster
Mountains graphic with white diamonds on itGeoscience and Exploration

Geophysical Data Enhancements

Online pre-recorded

Author(s)

A.M. Mirza (Presenting)
NTGS

The Northwest Territories Geological Survey (NTGS) holds a large collection of industry and government geophysical data. Assessment reports containing the results of exploration work are submitted to the Government of Northwest Territories (GNWT) by members of the mineral exploration industry under the NWT Mining Regulations (and before April 2014, to the federal government under the Canada Mining Regulations). Submitted assessment reports are released to the public after the period of confidentiality has expired. Early assessment reports contained no digital data, however, starting in the 1980s, geophysical surveys began to appear with assessment report submissions as manipulable digital data. These digital data are available online in the originally submitted form through the NTGS.

The NTGS not only makes the raw data available to the public but is also using the submitted data to create useful products that were not provided in the original assessment report. Examples of these products include grids of calculated parameters; databases in GDB format; merges of adjacent surveys from different assessment reports; and corrections of errors that are found. These enhancements are published as NWT Open Reports. Industry-standard geosoft formats are used, and in addition, new interpretive and original grids are converted into georeferenced tiff images for the user’s convenience.

Three-dimensional (3D) magnetic inversion and enhancements of two assessment reports (083838 Benjamin Lake area and 083912 Wecho River area) are presented in the poster. The 3D magnetic inversions are performed to enhance the visualization of structural features and magnetic bodies. 3D Inversion is the mathematical calculation that transforms raw geophysical measurements (in this case magnetics) into a 3D distribution of physical rock properties. In these enhancements, aeromagnetic data is transformed in a 3D model of magnetic susceptibility below the surface. Geosoft’s VOXI module is used to perform the 3D inversion. Input data for the inversion is the residual magnetic field. The inversion was carried out with no constraints and topography is included. 

These enhancements can be used to provide constraints on the geometrical signature and structural orientation of magnetic sources that could be related to mineralization of interest, especially kimberlite, gold, and VMS occurrences. The complete enhancements methodology (geophysical data enhancement methods with products) and 3D inversions parameters and results will be published as NWT Open Reports in near future.

PDF Available Upon Request.