Applications of Remotely Sensed Data in Geoenvironmental Assessments

Abstract

Remote sensing data and present-day analytical methods provide excellent tools for aiding in mineral resource and geoenvironmental assessments. Modem digital imaging systems, both airborne and satellite-borne, are providing a new array of coarse to fine spatial resolution and broad to narrow spectral resolution image data that are suitable for integration into geographic information systems (GIS). GIS evaluation of these data, along with information from many other sources, must be considered when conducting these assessment studies. The scope of remote sensing applications is changing from an emphasis of interpreting photographic images to data analysis and integration with other digital geospatial information. This integration substantially leverages the value of remotely sensed data, especially in the context of rapid growth and development of the quality and availability of digital information in general, and of satellite and airborne image information in particular. Various types of remotely sensed data have been used in mineral and environmental studies conducted by the U.S. Geological Survey (USGS). The scales of these applications have ranged from broad regional characterizations to local, site specific studies. Multispectral satellite data and airborne magnetic and radiometric data were compiled for the State of Montana, north-central USA. These layers of information were integrated to assist in identifYing areas at possible risk of surfacewater contamination by metals derived from past and present mining activity, from natural sources, or both. Imaging spectroscopy (hyperspectral) data have been used by the USGS to effectively map the locations of acid-producing minerals at mine sites in the Leadville mining district of the Colorado Mineral Belt, west-central USA. Thermal infrared image data have been used to identifY source rocks of alluvial materials associated with environmental problems in national parks, and to produce maps of primary rock composition and alteration information. Together, these applications of remotely sensed information have been used to (1) identify areas of potential environmental concern at regional and local scales, (2) assist in prioritizing drainage basins for mitigation efforts, (3) prioritize mine waste piles within selected drainage basins for remediation, and (4) guide remedial work by mapping geologically favorable and unfavorable repository sites.