Airborne Gravity 2010 - Geoscience Australia

Airborne Gravity 2010
database was upgraded. The airborne gravity survey now covers a large portion of central British
Columbia (Figure 1) and is an important regional geoscience data set. After releasing the data,
additional interpretation work has linked the different data sets together and added value to each.
Figure 1. Regional airborne Bouguer gravity data sets, British Columbia. The data set is a
composite of the three Quest surveys funded by Geoscience BC and the 2007 Nechako survey
block funded by the Geological Survey of Canada.
Regional gravity
In 2007, airborne gravity was a relatively new method without a strong history of success in mineral
exploration. However, an AIRGrav survey (Sander and Ferguson, 2010) in the Timmins, Ontario, area
provided a comparison between ground gravity and airborne gravity (Elieff, 2003; Sander and Elieff,
2004). This highlighted the quality of the new airborne data set, and provided an opportunity to review
its utility.
Barnett and Williams (2007) have shown that regional gravity maps are a very powerful indicator of
mineralizing controls. In a case study of the Timmins region, gravity was shown to be the second most
relevant exploration data set for localizing mineralization, after geological mapping (Figure 2). When
arguing for airborne gravity data in BC, this unbiased empirical evidence helped to carry the day, in
combination with the GBC project team’s strong support for the acquisition of regional gravity, and with
GBC’s desire to acquire useful new exploration data. Thus, a decision was made to acquire regional
airborne gravity data in Central British Columbia.
Survey area selection
Figure 3 shows the location of the Quesnel terrane, which hosts a number of alkalic Cu-Au deposits.
There is a large area without known deposits between Mt. Milligan and Mt. Polley. This area surrounds
Prince George and coincides with the region of drift cover that has discouraged mineral exploration.
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