Structural Interpretation of RADARSAT-1 Principal Components Imagery and Its Potential Application to Kimberlite Exploration in the Buffalo Head Hills Area, North Central Alberta

Principal components analysis (PCA) of RADARSAT-1 satellite imagery has been used to enhance the interpretation of surface features that may reflect underlying bedrock structures. Application of this technique in the Buffalo Head Hills area of north central Alberta, a region of active kimberlite exploration, suggests that the results may provide an indication of deeper crustal structures that controlled the emplacement of kimberlite intrusions. The method may, therefore, provide an important first-pass tool for exploration.

Four RADARSAT-1 principal components (RADARSAT-1 PCs) were extracted from RADARSAT-1 Standard Beam Mode S1 and S7 scenes, acquired in ascending and descending modes of the satellite's orbit (I.e., flying south to north and vice versa). A structural analysis of the principal component images provided sufficient detail to outline the major lineaments characterizing the meso- and mega-scale structures of the Buffalo Head Hills. The use of the PCA method minimizes data redundancy inherent in the RADARSAT-1 images and emphasizes the unique information contained in each scene as a response to the radar backscattering to surface roughness, surface dielectric properties, slope attitude and vegetation canopy variations.

North- and north-northeast-trending lineaments that bound the eastern edge of the Buffalo Head Hills along the Loon River graben were delineated. A conjugate set of northwest and northeast-trending lineaments that form block fault structures within the Buffalo Head Hills and along the eastern boundary have been outlined. East-northeast trending lineaments have been identified as the latest event in the area that offset the north-, northeast-, and northwest-trending structures. These structures extend throughout the Buffalo Head Hills and Loon River graben.

Integration of RADARSAT-1 PC image and digital elevation models (DEM) of the surface topography and Precambrian basement have been used to extract key structural and morphological features, which have then been compared with the locations of known kimberlites. Interpreted surface intersections of north-northeast, northwest and east-northeast-trending lineaments show first-order spatial correlations with these kimberlite occurrences. The youngest east-northeast-trending lineaments are thought to be of middle to upper Cretaceous age and may, therefore, have influenced the locations of kimberlite emplacement, which is believed to have occurred during the Upper Cretaceous.