A SIMPLE TECHNIQUE TO IDENTIFY MAGNETIC-ANOMALIES DUE TO KIMBERLITE PIPES

Most of the world's known kimberlites have distinctive geophysical sig natures, generally magnetic and/or electromagnetic. In the Canadian Sh ield, their aeromagnetic signature is often that of a circular anomaly . Target selection from aeromagnetic data is, therefore, based on the identification of roughly circular anomalies. This procedure can be au tomated by using known pattern recognition techniques. One of them is to compute, over a moving window, a first-order regression between a t ypical model anomaly and the aeromagnetic data. Only the results where the absolute value of the correlation coefficient is above a certain threshold are retained. Other criteria are later used to further refin e the selection. The locations of these solutions are then plotted on the aeromagnetic map and, if available, on a conductivity map. The Kir kland Lake region was selected to test the methodology and the propose d technique has been able to identify known kimberlites.