Spectral reflectance response of big sagebrush to hydrocarbon-induced stress in the Bighorn Basin, Wyoming

A geobotanical reflectance study was conducted at five areas in the Bighorn Basin of Wyoming to determine if the spectral responses of sagebrush could be a useful fool in hydrocarbon exploration. Measurements were collected in the visible and near infrared regions (0.45 to 1.1 μm). This investigation shows that a consistent and significant blue shift (to shorter wavelengths) of the green peak (0.56 μm) and red trough (0.67 μm) positions is the most reliable indicator of hydrocarbon-induced stress in sagebrush plants. This shift can only be defected where the sage is actually growing in large amounts of surface-visible or near-surface hydrocarbons. Spectral reflectance intensity data were found to have no significant correlation with the presence or absence of surface or subsurface hydrocarbons