Spectral stratigraphy: Remote sensing lithostratigraphic procedures for basin analysis,central wyoming examples

Stratigraphic and structural analysis of the Wind River and Bighorn basins of central Wyoming are in progress. One result has been the development of spectral stratigraphy, an approach to stratigraphic analysis that uses photogeologic and spectral interpretation of multispectral image data combined with topographic information to remotely characterize thickness and lithology of strata exposed in sedimentary basins. Thus, spectral stratigraphy is a new tool for use in integrated investigations of the evolution of sedimentary basins.Multispectral sensor systems that have been available since 1982 are used to analyze upper Paleozoic and Mesozoic strata on the southern margin of the Bighorn Mountains and the southern edge of the Bighorn Basin. Thematic Mapper (TM) data are used to develop stratigraphic columns and structural cross sections that are correlated with conventional surface and subsurface sections. Experimental thermal infrared aircraft data facilitate lithofacies/biofacies analysis of the monotonous Cretaceous Cody Shale sequence. Recently developed satellite and aircraft systems provide sufficient spectral resolution to allow for remote determination of the stratigraphic distribution of quartz, calcite, dolomite, gypsum, specific clay species, and other minerals diagnostic of depositional environments. Development of a desktop, computer-based, geologic analysis system that provides for automated stratigraphic interpretation and analysis of combined multispectral image and digital topographic data portends major advances in the application of spectral stratigraphy.Results demonstrate an approach with general applicability in other geologic investigations that could benefit from remotely acquired information about areal variations in sequence, attitude, thickness, and lithology of strata exposed at the Earth's surface.