West-East core-based cross section through the middle to upper Green River formation, Uinta Basin, Utah - Plate 1

Conclusions/observations from west-east cross section: The top of economic oil shale was picked at the top of the lower R-8 zone (top of the Big Three rich oil shale beds). This zone was selected to avoid the abundant saline minerals found in the overlaying saline zone, which often contains high-TDS water. If saline minerals (and high-TDS water) do not adversely affect potential extraction techniques, the top of economic oil shale could be extended to include the middle R-8, but only in the basin's paleo-depocenter. The base of economic oil shale will depend on specifications of potential extraction technologies. Maximum depth might be the base of the R-4 zone. The Mahogany zone (MZ), the richest oil shale zone, and the lower R-8 are dominantly calcareous mudstone, with thin beds of clay-rich and dolomitic mudstone. The upper and lower R-6 zones are dominantly dolomitic to clay-rich mudstones. The R-5 and R-4 zones consist of interbedded organic-rich clay-rich mudstones and organic-lean dolomitic mudstones in ~10 ft cycles. The higher MgO oil shale zones (R-6, R-5, R-4) and the more calcareous, lower MgO (MZ, R-8) oil shale zones will most likely have somewhat different thermodynamic properties, affecting potential extraction techniques. In general, rich zones are thickest and richest in the basin's paleo-depocenter represented by the Coyote Wash 1 core. Thin oil shale breccias are only found in the lower R-8, MZ, and R-6 in the paleo-depocenter of the lake (Coyote Wash 1 core), somewhat thickening the rich zones in this area. Minor saline mineral depositon occurred within the upper MZ and A-groove in the paleo-depocenter of the lake, possibly due to a lake regression/salinity increase related to the deposition of the organic-lean, dolomite-rich A-Groove. Lean zones are mostly composed of organic-lean mudstone, siltstone, and sandstone and thin significantly to the east, but thicken again in the south (Skyline 16 core) due to deltaic sands entering the basin. Siliciclastic-dominated lean zones record periods of high sediment supply sourced from active basin margin delta or mouthbar systems. Carbonate-dominated rich zones record periods of low detrital sediment supply. The saline zone thins to the east due to the deposition of volcaniclastic debris flows, possibly representing an influx of fresh water, creating a localized freshing of the lake. The large nodule saline facies is only found in the basin's paleo-depocenter (east side of cross section), but the small saline crystal facies seems to extend across the basin, as evident in the 16X-23D-36 core.