USGS Home
Contact USGS
Search USGS

Remote Sensing/Imaging Spectroscopy

Project Home Geology Geophysics Remote Sensing Geochemistry Publications Gallery

"Remote Sensing" is the acquisition of information on an object using instruments that are spatially removed from the object. Aerial photography is a simple example. "Imaging Spectroscopy" is more complex and includes the collection, processing, and interpretation of multi-spectral remotely sensed data. The Upper Santa Cruz River Watershed Project uses high resolution visible-infrared multi-spectral data to map the surface distribution of minerals and vegetation. The data were collected by the NASA/JPL Airborne Visible and Infra-Red Imaging Spectrometer (AVIRIS). Each image is approximately 11 km wide. The pixel resolution is 17 meters and contains 224 channels of spectral data. The rate of data acquisition is 2 square km per second.

More Information on Imaging Spectroscopy at: USGS Spectroscopy Laboraty Site.

Most minerals can be discriminated and their aerial distribution mapped using AVIRIS data. Minerals produced by the hydrothermal alteration of rocks can be recognized using this technology. Most of the mineralization of the Santa Cruz River Watershed is associated with this type of alteration. Thus, it is possible to infer the general surface distribution of ore minerals based on the distribution of the associated non-ore hydrothermal minerals, e.g, goethite, limonite. Potentially toxic metals are frequently found in anomalously high concentration in ore minerals (particularly sulfide minerals). Oxygenated surface and ground waters break down many sulfide minerals, releasing toxic metals to solution. Consequently, AVIRIS mineral maps bear directly on the question of the sources and dispersal pathways for toxic metals through the environment.

NASA AVIRIS Coverage Over Study Area

More Remote Sensing

For further information, contact Trude King.