Geophysics
Description
Geophysics investigates the Earth's internal structure using physics and mathematics. The physical properties of earth materials such as density, magnetization, and electrical conductivity all allow inference about those materials to be made from measurements of the corresponding physical fields - gravity, magnetic fields, and various kinds of electrical fields. Geophysics uses sophisticated instruments to measure the Earth’s physical properties to understand the Earth’s structure and explore for resources. The Northwest Territories Geological Survey acquires new geophysical data by commissioning airborne surveys, and holds an extensive archive of pre-existing geophysical data for the NWT. Archived data can be evaluated, re-interpreted, or re-analyzed by a variety of means according to need.
Location
Geophysics data is available for many areas of the Northwest Territories, however coverage is not uniform. Some regions, like parts of the central Sahtu and the southeastern part of the South Slave region, have higher resolution data than other regions.
Justification
Geophysical methods are very beneficial and cost effective in the world of resource exploration. These methods enable surveying of large areas relatively quickly compared to other scientific techniques. Different geophysical techniques can be applied to solve complex problems. The more physical properties that are evaluated, the less ambiguous the interpretation becomes. Most geophysical methods are non-invasive and environmentally friendly. Coverage of the NWT is uneven, with some types of data, such as magnetic data, being much more common than others, such as gravity or electrical data.
Approach
The NTGS holds a large collection of industry and government geophysical data to which value will be added by re-analysis and interpretation. In addition, new geophysical data will be acquired over areas of high interest.
Schedule
Projects completed include an interpretation of magnetic and radiometric data that is now being used by the geologists on the South Nahanni project, and a compilation of government aeromagnetic survey metadata. A comprehensive evaluation and re-interpretation of industry-acquired geophysical data in the NTGS archives is currently underway. Additional projects, including acquisition of new data, will be undertaken according to NTGS priorities.
Keywords
Geophysics, airborne data, aeromagnetic data, magnetic, airborne radiometric, airborne spectrometry, electromagnetic data, gravity, airborne gravity, induced polarization, direct current resistivity, anomaly