Abstract

The Tertiary Norwood Tuff, north of Mountain Green, Morgan County, Utah hosts a clinoptilolite occurrence which was discovered in the 1950s but which is only sparsely reported in the literature. In order to encourage development of this geologic resource, an investigation was initiated to gather data on the mineralogy, thickness, richness, lateral extent and potential uses for the zeolitic tuff in this occurrence.

Methodology consisted of a thorough literature review followed by mapping and sampling of the occurrence. Altered tuff beds were located on aerial photos and then mapped in the field at 1:24,000 scale. The thicknesses and strikes and dips of the zeolitic units were also measured. Grab samples were taken from representative outcrops and sent to an analytical laboratory for determination of mineralogy and clinoptilolite content by X-ray diffraction and cation exchange capacity (CEC) of the zeolite by the ammonium method.

The investigation delineated a large, high-potassium clinoptilolite occurrence of good purity and moderate cation exchange capacity. Five zeolitized airfall tuffs of the Late Oligocene to Early Eocene Norwood Tuff constitute the resource. These tuffs crop out in a north-south trending syncline of Basin and Range extensionsl origin. The syncline extends six miles north-south and three miles east-west. Assays of individual grab samples yielded grades as high as 85% clinoptilolite with cation exchange capacities up to 2.3 milliequivalents per gram of tuff. Zeolite mineralization shows good vertical and lateral continuity. Two measured and sampled sections in an altered tuff unit (unit C), at locations 2.5 miles apart were both 37 feet thick and had comparable vertical variation in clinoptilolite content and cation exchange capacity.

There is high potential for production of clinoptilolite from this occurrence especially for local uses involving agriculture and pollution control. Possible agricultural uses include as a component in fungicide and fertilizer, as a livestock holding pen deodorant and as a livestock feed supplement. Possible pollution control uses include as a slow sand filter media for municipal wastewater treatment and as an absorbent in in-situ hazardous waste treatment.