Lode Gold — JOSEPHINE County

Source: Tom Ashworth's Prospectors Cache (tomashworth.com / Mike Higbee / 49erMike). Author: Tom Ashworth. Original page: josephine_or.shtml. State index: https://web.archive.org/web/20040830075749/http://www.tomashworth.com/goldloc.shtml Area: Lode Gold. Map coordinates are an approximate county centroid — not a precise claim site. The geology of Southwestern Oregon is complex and not fully understood, being closely associated with plate tectonics and crustal subduction. Numerous gold-quartz veins can be found in greenstone of Triassic age, which trends in belts from the southwest to the northeast parts of Josephine County. Black slate, peridotite, and serpentine of Jurassic age sometimes contain gold-quartz veins and tend to parallel the greenstone belts. Granite, diorite, and gabbro intrusive bodies of Jurassic and Cretaceous age can be found in many parts of the county, but are generally devoid of mineralization except where they are in contact with older rocks. Josephine County is noted for past chromium, copper, and nickel production as well as gold, and exploratory work for nickel continue to this day. The most productive lode gold mine was the Greenback (see map), which produced some 175,000 ounces of gold from a persistent quartz vein in greenstone. It was sunk to an inclined depth of 1,000 feet on 12 levels. The Benton Mine was developed in gold-quartz veins in greenstone near the contact with intrusive diorite, and produced 18,500 ounces of gold. The nearby Gold Bug Mine produced 37,500 ounces. Numerous other lode mines produced between 1,000 and 13,000 ounces of gold, primarily in the period between 1893 and 1942.