| The quantitative mapping of vegetative cover poses a potential means for providing geological information in Canada. This research addresses: (1) the spectral reflectance characteristics of major tree species of the boreal forest which have been subjected to geochemically-induced stress; (2) the detection of geochemically-stressed vegetation from airborne and satellite sensors; and (3) the use of satellite remote sensing techniques in mapping surficial units in glaciated forested environments.; Two near-surface minearalized sites in the Canadian Shield were studied to address the first two questions. Till in the White Lake site in northern Manitoba contains 150-3000 ppm of Zn-Cu-Pb. The Natal Lake site in northern Ontario is an area of lower mineralization with geochemical values varying from 50-400 ppm of Cu-Ni-Mn-Zn in the till.; Areas of high mineralization (the White Lake site) produced characteristic spectral responses for vegetation growing on the site. Increases in reflectances at the chlorophyll absorption minimum, near 680 nm, a 'blue shift' at the red reflectance edge, and a decrease in reflectance at the infrared plateau were documented. In areas of lower mineralization (i.e. Natal Lake), the spectral changes of major tree species were very subtle. Increases in the magnitude of the infrared reflectance at the shoulder were recorded. These observations provide the basis for the detection of anomalous spectral reflectance characteristics in the development of high resolution multispectral systems and imaging spectrometers.; Spectral signatures related to localized geochemically-stressed vegetation can be detected by high resolution narrow-band airborne multispectral scanner data. For the White Lake site, the detection was based on a combination of principal component and ratio enhancement techniques of selected narrow-band imagery.; The third investigation is a regional geobotanical study. This involved the use of laboratory spectral reflectance measurements, LANDSAT MSS, TM and airborne radar in providing information on surficial material in The Pas area of Manitoba.; Laboratory measurements or the spectral reflectance of surficial materials were conducted to understand the factors which can aid in their discrimination.; Regional vegetation distribution mapped at a scale of 100,000 from the LANDSAT MSS data coincided with glacial, alluvial and organic deposits. (Abstract shortened with permission of author.)... |
