The ore trend explored by Western Nuclear, Inc. at Smith Lake, lies in approximately six sections in T15N, R13W of McKinley County, New Mexico. All of the orebodies lie within the Brushy Basin Member of the Jurassic Morrison Formation which contains essentially three distinct sandstone units at this location. For exploration purposes this breakdown is adequate, although the sandstones do become exceedingly complex on a small scale.

The Smith Lake ore lies along the southern margin of the Chaco slope. The regional dip is quite uniform at about 2° north-northeast. North of the deposits running subparallel to the east-west ore trend is the Mariano Lake anticline. At the west end, the anticline dies out at the Pinedale monocline and does not extend to the Bluewater fault zone on the east. The Bluewater fault is a normal, high-angle fault, downthrown to the east, and essentially forms the eastern boundary of the area.

The orebodies are aligned approximately east-west and are generally arcuate. The geometry of the ore is controlled by the stream-channel systems in the Brushy Basin sandstones. Some of these orebodies coincide with the redox interfaces that have been found. Those that do can assume the geometry of a typical roll-front type of orebody.

Three hypotheses for depositional controls are: (1) Laramide structures are spatially associated with the ore and have been considered by some geologists as a depositional control; (2) the change of lithologies from sandstones to mudstones down the hydraulic gradient also may have affected ore deposition; and (3) stream channel systems with carbonaceous material localizing the ore is a viable control as well.

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