Abstract

Teapot Dome is an asymmetric, basement-cored, Laramide-age anticline. A systematic study of natural fractures indicates that lithology and structural position control outcrop and subsurface fracture patterns. Three throughgoing fracture sets were documented within this context. The oldest fracture set, containing relatively few fractures, is oblique to the hinge of the anticlinal fold. The majority of these fractures strike NW to WNW and abutting relationships indicate they predate folding. A second set of fractures consists of bed-normal extension fractures striking subparallel to the fold hinge. A third set consists of bed-normal extension fractures striking normal to the fold hinge. In many areas this fracture set is spatially related and subparallel to NE-striking, normal dip-slip and normal oblique-slip faults that maintain a roughly perpendicular orientation to the fold hinge. Fractures, deformation bands and faults, with conjugate geometries oriented such that they have a vertical bisector to the acute angle and strike subparallel or normal to the axis of the anticline and have a normal sense of displacement, are also observed. Analyses of 3-D seismic data allow mapping of subsurface structural features. Structural trends vary slightly with depth, suggesting a slight difference in orientation between basement fault blocks and applied Laramide stresses responsible for uplift of Teapot Dome.