Analysis and reprocessing of airborne gravity gradiometer data over the Strange Lake rare Earth deposit, Québec-Labrador

Abstract

A high-resolution airborne gravity gradiometer survey was flown in March 2012 over the Strange Lake intrusive complex, located on the border of Québec and Newfoundland and Labrador. This survey provided an opportunity to better understand the performance and limitations of this technology and also investigate potential improvements to the associated data processing. Airborne gravity gradient data low-pass-filtered at 75 m, rather than the standard 300 m, were provided by the contractor for this purpose. One flight line was reflown several times and used to assess the repeatability of the data, showing that in this particular area, the airborne gradient gravity system has a full-sine (wavelength) resolution of about 700 m. The system can therefore detect anomalies having a width of about 350 m. We also found that for gradiometer data, kriging is a better interpolator than low-pass filtering combined with minimum curvature gridding. Using kriging, line-to-line correlation (and in some cases, resolution) appears slightly improved.