| Description |
Sandstones from the bitumen deposit near Sunnyside, Utah, exhibit many diagenetic modifications that should be considered in any attempt to recover the bitumen. The sandstones generally are subfeldspathic to feldspathic arenites, with varying amounts of carbonate lithic fragments. Detrital feldspars have been partially dissolved to partially cemented by overgrowths, whereas quartz grains have developed syntaxial overgrowths. Many minerals, including quartz, feldspar, illite, mixed-layer illite/smectite, chlorite, kaolinite, zeolites (largely analcirae), calcite, dolomite, siderite, and ankerite, are cements in the sandstones. The amount of any one cement varies considerably from sample to sample. Some minerals, such as dolomite and kaolinite, also replace the detrital grains: dolomite replaces detrital quartz and feldspar, and kaolinite commonly replaces feldspars and carbonate clasts. All of these authigenic minerals serve to reduce permeability and porosity and increase the surface area of the grains facing the pores, and will have a deleterious effect on recovery attempts. |
