Tuscarora District

The Tuscarora Mining District is within a major gold producing region of Nevada. Placer gold was discovered in the district in 1867 and production of silver-gold lode deposits began in 1875 (LaPointe, et al., 1991). Total precious metal production between 1867 and 1990 consists of >500,000 ounces of gold and 7,632,000 ounces of silver from quartz veins and quartz stockwork mineralization.

Since 1982, the Tuscarora District has had a sustained, exploration effort. This effort has been almost continuous, with each subsequent operator building on the previous work. Ultimately, this work led to the area covered by the Tuscarora Project.

The Tuscarora Project lies south and east of the Dexter historic open-pit. Newcrest drilled this area and noted numerous significant gold values for the South Navajo Vein and East Pediment areas. With up to 5 feet, grading 182 g/t Au in drill hole TN38, in the South Navajo Vein area. Their assay values indicated narrow and somewhat discontinuous shoots of high-grade gold. Newcrest also described coarse visible gold that created a metallurgical nugget effect.

The Great Basin in Nevada is a westward thickening wedge of carbonate and siliciclastic rocks deposited along a craton margin over hundreds of millions of years. The regional structural setting is simply portrayed as older Paleozoic and Mesozoic rocks above younger Paleozoic and Mesozoic rocks. Multiple global scale tectonic events pushed eastward, developing low-angle thrust faults that juxtaposed siliciclastic and carbonate rocks. In the late Mesozoic and early Cenozoic, extensional tectonic events led to multiple volcanic and intrusive events that continue into modern times. In this region of the Great Basin, three lithologic domains developed during the Cambrian to Late Devonian. Shallow, platform carbonates and shelf-slope carbonates formed the earliest domain as a westward-thickening wedge along the passive margin edge of the North American craton. A second domain formed in the Ordovician from deep-water ocean basin siliciclastic, volcanic, and volcaniclastic rocks to the west. The third domain is the result of the Antler highland emerging along the leading edge of the Roberts Mountain Thrust with subsequent erosion and deposition of the sediments along the eastern margin of the highland and into the foreland basin. In the early Tertiary, a period of extensive silicic volcanism occurred throughout a large portion of southwestern North America.

The Tuscarora volcanic field developed during this period and is one of the largest examples of Eocene age magmatism in Nevada. The most intense magmatism occurred to the southeast in an area that encompasses at least five major volcanic centers including the Mount Blitzen volcanic center.