Seismic Exploration in Rocky Mountain Region: ABSTRACT

Abstract

Structurally and stratigraphically, modern exploration in the Rocky Mountain region depends increasingly on seismic delineation of prospective targets. In many areas an integration of geology and geophysics is required for a viable prospect today. Structurally, the unique Rocky Mountain foreland deformation would have remained an enigma without modern seismic efforts and its pursuant drilling. This recent work resulted in several dramatic discoveries beneath thrusted Precambrian rocks. Continual drilling success in the Overthrust belt (where structure is largely masked by Tertiary sediments) has been the result of integrating new subsurface data with improved seismic work. Basin and range deformation, in many places superimposed on the complexities of low-angle thrusts or hidden by volcanic cover is severely testing seismic acquisition technology and interpretation skills. The challenge to acquire good seismic data from beneath thick volcanic fields has been successful in Colorado and Wyoming. Angular unconformities are often clearly visible on seismic sections where they were difficult or impossible to recognize because of the absence of paleontologic data or because the strata above and below the erosional surface are too similar. Detection of angular discordance not only sets up the potential for locating truncation or pinch-out traps, but also enlarges our understanding of the tectonics and timing of Rocky Mountain deformation. Pennsylvanian deformation was as consequential in the Rocky Mountains as Laramide deformation, but is commonly masked by undisturbed Mesozoic rocks. Detection of these faults and folds has been greatly enhanced by seismic data, as well as deep-seated basement faults whose recurrent movement has controlled overlying stratigraphy. Stratigraphic exploration in Rocky Mountain basins has challenged both geologists and geophysicists and they have joined in an increasingly sophisticated search for traps in sand dunes, fluvial channels, incised valley, delta fans, salt-solution structures, carbonate banks and reefs, karst topography, and sometimes in poorly understood, but equally prolific, simple porosity and/or permeability barriers. End_of_Article - Last_Page 849------------