Remote sensing characteristics of the sediment- and volcanic-hosted precious metal systems: Imagery selection for exploration and development

The precious metal class of ore deposit is composed of several subtypes. Occurrences are dominated by systems of hydrothermal origin commonly classified by physical geologic features that relate conveniently to remote sensing. Variability between types of deposits is an important consideration in the selection, application, and interpretation of remote sensing data. This paper outlines and compares both the physical geologic features and the important remote sensing characteristics of the economically important sediment-hosted and volcanichosted types. The spectral and spatial resolution requirements of the significant deposit features - primary alteration, secondary alteration, host rocks, structure, zoning relationships, and vegetation - are reviewed. Exploration strategies and project scales, including reconnaissance, regional, district and deposit scales, influence spatial resolution requirements. Hyperspectral imagery and spatial resolutions of up to 3-4 m are required to satisfy some detection and mapping objectives at some precious metal projects.