Key to Formation Symbols Used on Field Trip Route Maps (Figures 7 and 8)
This trip traverses Middle Ordovician and Lower Ordovician Knox Group strata enroute to American Smelting and Refining Company's (ASARCO) Young mine and mill complex (Stop 1). The Young mine, located near the center of the Mascot-Jefferson City zinc district, is the largest of the operating mines. The ore occurs mainly in collapse breccias which will be observed during an underground mine tour led by ASARCO staff.
The trip retraces the route to Knoxville, then turns southwest to the Sweetwater barite district traversing mostly Knox Group formations. The Stephens barite mine, the only currently active mine, as well as the largest producer over the district's 100-year history, can be seen in passing. The shaft site for the 1970's U.S. Borax Company fluorspar project is just down-dip (southeast) from the Stephens site.