Aircraft Scanner Studies of Surface Hydrothermal Alteration-Waiotapu Geothermal Field

Abstract

GEOSCAN MKII multispectral aircraft scanner imagery acquired over the Waiotapu geothermal field at 3 m spatial resolution is evaluated for surface mineral studies. Previous investigations showed that colour composites consisting of visible, NIR and MIR wavelength bands are valuable for mapping vegetation, water bodies and hydrothermally altered ground. This study examines the use of the GEOSCAN 18 reflective wavelength bands for the identification of minerals present in the altered ground. Spatial profiles along transects and spectral profiles for selected sites are presented. These data are interpreted using GEOSCAN colour composite images, aerial colour photographs, field survey infoxmation and laboratory analyses of samples to evaluate the role of high resolution aerial scanner data for detailed mapping of the complex patterns of minerals present in hydrothermally altered ground at Waiotapu.