Deep basement reflections in Wind River Line 1

COCORP, Consortium for Continental Reflection Profiling, has acquired 24‐fold VIBROSEIS reflection seismic data from the Wind River uplift region of Wyoming. Beneath the Green River Basin (with more than 10 km of sedimentary rocks), the data contain subhorizontal reflections from deep within the Precambrian crystalline rocks, but beneath the Wind River Range (where the crystalline rocks reach the surface) these deep events are comparatively weak or absent. This difference is interpreted as a consequence of the deterioration of the stacked data in the geologically complex, laterally inhomogeneous region beneath the Wind River Range rather than as evidence that the deep events beneath the Green River Basin are multiple reflections from the sedimentary section. Adaptive deconvolution followed by bandpass filtering helped to discern the true nature of the deep basement events. The results indicate that although some of the deep events were attenuated by the combined adaptive deconvolution‐bandpass filtering procedure, others were enhanced by it. From this it is concluded that at least some of the deep events from within the basement rocks represent primary reflections from unknown geologic “horizons.”