Mineral resources of the Big Frog Wilderness Study Area, Polk County, Tennessee and Fannin County, Georgia

Abstract

The proposed Big Frog Wilderness is comprised of approximately 1820 hectares (18.2 km 2 ) of mountainous terrain in the Cherokee and Chattahoochee National Forests south of the Ocoee River in Polk County, Tennessee, and Fannin County, Georgia. Rocks of the study area are greenschist-facies metasandstone, meta-arkose, metagraywacke, and dark slate of the Ocoee Supergroup of late Precambrian age. A major thrust fault, correlated with the Greenbrier Fault, separates fine-grained slaty rocks of the Snowbird Group on the northwest side, from coarse clastic sediments and interbedded slates of the Great Smoky Group on the southeast. North- and northeast-trending folds are common in the map area. Minor deposits of Quaternary sand and gravel occur locally in the lower parts of large streams. Semiquantitative spectrographic, atomic absorption, and selected fire assay analyses were done on more than 200 samples of rock, soil, and stream sediment. No significant metal anomalies were found for 31 major, minor, and trace elements. In many places, metasiltstone and metasandstone contain trace amounts of chalcopyrite and sphalerite as microscopic intergrowths with the chief sulfide minerals, pyrite and pyrrhotite. Sulfides make up as much as 5 to 10 percent of some rocks and provide concentrations of Cu, Zn, and As slightly higher than background in samples of rock and soil. Rocks containing these disseminated base-metal sulfides are of insufficient grade to have current economic potential, however. No metallic mineral resources are known within the proposed Big Frog Wilderness. Nonmetallic resources, including slate and phyllite, stone, and sand and gravel are present locally, but are not presently a value because similar resources exist closer to markets outside the study area. These deposits therefore would have only marginal use in the region.