Gelder Mine, Pioche Mining District, Lincoln County, Nevada, USAi

Regional Level Types
Gelder Mine	Mine
Pioche Mining District	Mining District
Lincoln County	County
Nevada	State
USA	Country

Structure: Bedding Plane Shear Zone, Slickensides

Alteration: Argillic, Bleaching, Silicification

Deposit: Lower workings are in pioche shale and explore a S-dipping low angle fault which is intersected by a n60e, 75 SE shear. Rocks are argillically altered and stained with Fe-Mn oxides, and abundantly stained with psilomelane. Shear separates prospect mountain quartzite on NW from pioche shale on se. The shear zone is hydrothermally altered and gossany. At the main adit, above the lower workings, limestone beds strike n35w, dip 30 s W and are bleached and altered, with an exposed bedding plane shear zone heavily stained with Fe-mn oxides. Most of the dump material at the adit is pioche shale while main ore bin is full of quartzite and limestone carrying minor grains of galena and pyrite in quartz veins. The adjacent shaft is caved in. At the shaft, a rib of silicified siltstone/limestone is cut by vitreous quartz vein carrying fine-grained oxidized pyrite/chalcopyrite, argentifereous galena and possibly sphalerite, and is stained with minor malachite and Fe-mn oxides. Most rocks exhibit slickensides. Mineralization occurs in fissure-filling quartz veins. Most pyrite is oxidized with malachite stain probably from oxidized chalcopyrite or tetrahedrite (?). Minor yellow oxides were note

Deposit type: Polymetallic veins

Development: Not active at time of examination in 1983

Rock formation(s): Pioche Shale, Prospect Mountain Quartzite;Lyndon Limestone


Ore(s): Intersection Of S-Dipping Low Angle Fault And N60e,75se Shear Zone

References

Other Databases

Link to USGS MRDS:	10046409