Abstract: A Structural Reinterpretation of Buck Mountain, Eureka Fold-and-Thrust Belt, Nevada

ASTLE, SUZANNE, JUDITH CHESTER, WALTER SNYDER, and LEE M. LIBERTY

Previous structural interpretations of the Eureka fold-and-thrust belt, including Buck Mountain, Nevada, have assumed classic fold-fault geometries, uniform bed thickness, and strictly followed the rules of cross section balancing. However, recent geologic studies suggest that the assumption of uniform thickness, i.e. simple layer-cake stratigraphy, may be inappropriate. Rather, multiple unconformities and phases of minor deformation during the Paleozoic contribute to an already complex Mesozoic and Cenozoic structural configuration. Field mapping and a recent exploratory well also show that the structure of Buck Mountain is more complex than previously thought.

Reprocessing of an east-west oriented seismic line was done to better constrain the geologic subsurface interpretation. However, a major problem in processing seismic data from Nevada is the poor quality of images produced by the Paleozoic bedrock in the ranges and beneath basin-fill sediments. Therefore, in an attempt to get the most from the available data, detailed attention was paid to the development of the near-surface model. This enabled more appropriate field statics to be applied to the data and determination of better velocities for NMO and migration. Evidence of the complex geology was also observed in the seismic data during reprocessing. Reprocessing of the data was done using ProMAX, industry-standard seismic processing software from Advance Geophysical.

These geophysical data, when combined with the surface geologic data, have allowed a more accurate, although more complex, geologic cross section to be constructed.

AAPG Search and Discovery Article #90946©1997 AAPG Rocky Mountain Section Meeting, Denver, Colorado