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Regional Distribution of the Mancos Shale (remote sensing and stratigraphic mapping)

Task Objectives

Map the Mancos Shale using spatial and spectral remotely sensed data on both regional and local scales. Lithology, mineralogy, structure, geomorphology, vegetation, and land-use were characterized using Landsat Thematic Mapper (TM), NASA-ASTER, NASA-MASTER, air-photography, field spectroscopy, sample MASTER, and ancillary map data (digital elevation maps, digital line graphics, and geologic mapping). These data were used by the project to help define the Mancos Formation's sub-units, metal balance, salt and toxicology, ground-water system, erodibility, ecology, and land-use planning. These derived maps were georeferenced for use in GIS analysis and by the other tasks of the project. This task provided a stratigraphic framework based on remotely sensed data and minor detailed field mapping.

Highlights & Key Findings

Analysis of several remotely sensed data sets and field spectral measurements suggest preliminary findings of:

1. Mancos subunits are being defined in areas that have not been differenciated by field mapping. Soils generated from these subunits have compositional differences in mineralogy and mineral abundance. These variations in mineral type and abundance are being used to form a soils map with details not previously shown by traditional field mapping.
2. Comprehensive analysis of the Mancos within the study area has yielded advances in spectral mapping techniques and basic knowledge of surface mineralogy and composition that are being used to propagate the rapid mapping of soils throughout the region using lower resolution satellite data.
3. Spectral measurements of Mancos Shale in the field and laboratory have identified various clay, iron-oxide, and sulfate minerals that are associated with a variety of chemical and physical properties. These minerals have been identified in the field as enabling rapid erosion of the surface and may be one mechanism for transporting metals and salts from shale bedrock to the Colorado River system.

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