Exploration geophysics is used as a means of acquiring quality data to study geological variations within specific areas of the Earth's crust. The information gathered during a geophysical survey aids in the production of geophysical maps, which are utilized in the prospecting stage for mineral and hydrocarbon exploration.
The process of exploration geophysics commonly employs the use of airborne surveys as it is possible to survey large areas of terrain in a short time frame.
There are a variety of different types of airborne geophysical surveys, each with its own specific purpose. Airborne magnetic surveys are used as a means of detecting magnetic minerals and mapping geological structures. Radiometric surveys can directly detect the presence of uranium or potassic alteration, and are useful for mapping lithological contacts at surface. Electromagnetic surveys detect the presence of minerals that are more conductive or resistive than surrounding host rock. .
Airborne magnetic surveys are the most common type of airborne geophysical surveys, as they can be used for a variety of different purposes. As the traverse line spacing is decreased, the data resolution increases.
These varying degrees of traverse line spacing puts airborne magnetic surveys into two different categories: regional and detailed.
A regional airborne magnetic survey may have a traverse line spacing of more than 400 meters and may cover areas of several thousand square kilometres. Regional magnetic surveys are most commonly used to aid in reconnaissance geological mapping. They are also used for exploration of commodities such as hydrocarbons and other non-metallic resources.
Mining companies typically prefer detailed surveys that have a higher data resolution than regional surveys, as the traverse line spacing is less than 400 meters. A detailed airborne magnetic survey can be the first step in a successful mineral exploration project, because its data can show the presence of magnetic minerals such as iron ore, map structures, and indicate the locations of possible kimberlites .
Other uses of detailed airborne magnetic surveys are for locating basement targets in the exploration of hydrocarbons, determining minerals as either metallic or non-metallic and assisting with general geological mapping of an area.
Because the data acquired during an airborne magnetic survey can potentially lead to a valuable mineral discovery, it is of upmost importance that the data acquired is as accurate as possible.
Mineral explorations that have commenced under the pretenses of faulty acquired data during a geophysical survey have lead to major financial loss. Therefore, it is imperative that exploration companies wisely choose contractors that specialize specifically in conducting geophysical surveys, who are able to consistently acquire quality data using modern data acquisition systems and with properly qualified personnel.
Exploration geophysics is a highly recognized field to assist with mineral prospecting, mapping and acquiring a comprehensive understanding of the geology of specific terrain. Relied upon by governments, scientists and the mining industry, the quality and accuracy of data attained is of upmost importance.
Specialists in Airborne Geophysical Surveys
Terraquest was established in 1984 and since then, our dedicated team has flown over 1,500 airborne geophysical surveys using both fixed wing and helicopter platforms. Our professional crews provide significant experience having carried out airborne magnetic surveys, airborne gravity surveys, airborne radiometric surveys, and airborne electromagnetic surveys on five continents.
Our quality data sets have been utilized in the exploration for base and precious metals, kimberlite, hydrocarbons, uranium, rare earth minerals and water. The company has performed exemplary surveys for both small and large exploration groups as well as many government agencies. References can be provided upon request. Visit
www.terraquest.ca.
Ed. GMH