LiDAR altimetry and hyperspectral imaging: New technologies for geological and mineralogical mapping.

摘要

This thesis comprises several studies which use the relatively recently available commercial technologies of airborne LiDAR altimetry and hyperspectral imaging to investigate methods of lithological and mineralogical mapping. The study area covers approximately 3Q km2 near the City of Sudbury, Ontario, Canada. At the extreme northeast and southwest corners of this area are the Frood-Stobie mine and the Murray Mine respectively. Frood-Stobie is an active mine with current underground extraction of nickel ore. The Murray Mine, which was also worked for its nickel content, is now decommissioned. Both sites include waste rock piles which accommodate material extracted from nearby open pits.; A digital elevation model was created from LiDAR altimetry data and used for lithological studies. Discriminating lithology from elevation relies on recognizing lithological signatures inherent in the topography. Lithological studies are confined to the relatively undisturbed areas between the mines. Quantitative differences between lithologies in the study area have been established on the basis of morphometric and fractal analyses. Three geological units present in the study area exhibit topographic signatures which are sufficiently distinct and are discriminated by the morphometric measures of slope and curvatures. The unit most resistant to erosion, the granitic Murray Pluton, exhibits the steepest slopes and curvatures while the other two units, a norite and a gabbro, which are more erodable, have lower slopes and curvatures. In addition, fractal analysis, which characterizes the 'roughness' of the landscape, distinguishes between the units with the measure of fractal dimension (D). These analyses have recognized differences in the values of D as well as identified anisotropy in the landscape resulting from the different lithologies.; On a more detailed scale of mapping, one study has identified a northeast-southwest trend of topographic ridgelines. This correlates with a similar regional structural trend created by tectonic forces which helped to shape the Sudbury Basin. Older rock units such as the Murray Pluton exhibit additional ridgeline orientations reflecting the presence of earlier deformation events. This study establishes a link between the local topography and regional-scale tectonics which may be significant for other areas in the Sudbury Basin.; Hyperspectral imaging for mineral mapping focuses on the two mine sites and waste rock piles, with the aim of identifying alteration minerals associated with acid mine drainage (AMD). These studies have identified concentrations of iron-bearing alteration minerals associated with AMD, at both mine sites. (Abstract shortened by UMI.)