1. Look at the data, they appear to have been gridded at 30 meters. The data cover a huge area; gridding at 30m would take a long time. One could experiment on a representative subset. I chose to try a 100 meter grid interval. Note that choice of grid interval affects the radial power spectrum.

2. TMI gridded at 100 meters with minimum curvature

3. Radially averaged power spectrum for the data gridded at 100 meters. This follows iterative adjustment, I chose four layers.

4. Shallowest Dipole Layer

5. Second deepest equivalent layer

6. Third deepest equivalent layer

7. Deepest (4 th ) equivalent layer

8. TMI separated into four equivalent layers. The deepest layer is largely devoid of signal from the dikes The two middle layers contain most of the NW striking dike signal. Note that I limit the range of the color scale to accent the signal of interest.

9. Sum of the middle two equivalent layers (461 meters and 1533 meters) separated by matched filtering. The dikes are now the dominant signal but there are some interesting anomalies transverse to the dikes

10. Surfer includes simple (convolution) directional filters – you can use them to bias against directional signal in directional apertures

11. Application of Simple Directional Filters Signal with southwest strike removedSubsequent removal of northeast strike

12. TMITMI after filtering to separate dikes

13. Surfer color schemeGeosoft color scheme