Viper is an early-stage, low-sulfidation epithermal gold target, located in northeastern Nevada. The property comprises 40 unpatented lode claims under BLM jurisdiction, and additional lands held under agreements with third parties.
Viper is unusual in that vein and vein stockwork mineralization are hosted by Permo-Triassic silty limestone and silicified conglomerate which are overlain by (barren) Miocene rhyolite and dacite. The gold system is believed to be coeval with the felsic volcanic rocks, and similar in age and character to the nearby Jarbidge district
Work completed by Fronteer Gold in 2009 and 2010 defined multiple target areas on the basis of outcropping vein and vein/stockwork occurrences. Textures range from banded quartz/calcite to bladed and lattice textures typical of epithermal veins in active hydrothermal systems.
Rock chip samples from the Pilot claims and from adjacent ground now under option to Logan include multiple values in excess of one ounce gold, and contain visible gold in outcrop. A number of historic drill holes returned significant gold values.
Location and Land Tenure
The Viper property is located in Elko County, Nevada, approximately 60 km NE of Montello. It comprises 40 unpatented lode claims under BLM jurisdiction, together with ground held under agreements with third parties.
Geology and Alteration
Bedrock comprises a sequence of gently dipping and folded Permo-Triassic limestone and calcareous siltstone, unconformably overlain by Tertiary conglomerate. Miocene felsic volcanic rocks and associated intrusive domes are younger than the conglomerate, and are thought to be coeval with the gold mineralizing event.
High angle faults that are interpreted to be feeder structures to gold bearing fluids display several orientations including north-south, northwest, and northeast.
Alteration related to gold mineralization is dominated by silicification and decalcification as broad selvages to veins, particularly within calcareous siltstone host rock. Overlying conglomerate is also pervasively silicified although only rarely mineralized.
Gold mineralization at Viper is intimately related to the presence of quartz-calcite veins and vein stockworks. Individual veins exhibit spectacular bladed and lattice epithermal textures, and free gold is conspicuous in a number of outcrops. Exploration on the Pilot claim block returned surface rock samples to 11.8 g/t Au. Adjacent ground now subject to a lease/option agreement with Logan includes vein outcrops which have assayed up to 25.2 g/t Au over three meters. Silver and indicator metal abundances are low at Viper, although statistical analysis of soil sample data indicates a strong positive correlation between gold and iron.
In most respects, Viper is a typical low sulfidation epithermal project, although host rock (sediments) and trace element association (iron) are unusual. The current model for gold deposition envisages high angle faults as feeders with ascending hydrothermal fluids ponding beneath the impermeable rhyolite cap. Associated alteration is dominated by silicification and decalcification with gold deposited in reactive silty carbonate (Figure 2).
The Viper area was identified as a greenfields target by Fronteer Gold in 2009. The larger district has been explored by Fronteer, Pilot, and the Kuzma/Miranda/Ramelius joint venture. Technical programs have been comprehensive, including geologic mapping, geochemical sampling, hyperspectral studies, geophysical surveys, isotopic studies, and RC drilling.
Historic results in the Viper District - although encouraging – do not define mineable grades and widths of mineralization at appropriate depths. Logan believes another phase of targeting is required, and has moved to consolidate the district land package through a lease/purchase option agreement on adjacent claims. Work will focus initially on merging the historic databases to assemble a comprehensive, 3D district scale model designed to better define the main feeder structures. Logan anticipates this program of work will be successful in generating future drill targets.
Dr. Craig Bow, Vice President Exploration of Logan, is a Qualified Person (“QP”) as defined by National Instrument 43-101. The QP is a member in good standing of the American Institute of Professional Geologists as a Certified Professional Geologist (CPG.). Dr. Bow has reviewed and is responsible for the technical information disclosed on the website relating to the USA Gold Projects.