Jackson
Jackson-Plymouth Mining District, Amador County, California, USA
Key Information
Do not enter mining areas without proper authorization.
The Jackson-Plymouth Mining District in Amador County, California, is a historic gold mining area in the Sierra Nevada foothills, about 45 miles southeast of Sacramento.
It features a diverse range of minerals, including gold, uvarovite, diamond, and quartz, with gold being the most prominent.
The geology includes Jurassic slate, greenstone, and older metamorphic rocks, with gold found in veins and ancient river gravels.
Mining began in the mid-19th century, with key mines like Kennedy and Argonaut operating for nearly 90 years, leaving a rich historical legacy.
The area has a strong gold rush heritage, now complemented by a thriving wine industry, with a Mediterranean climate and varied ecosystems.
Geographic Location
The Jackson-Plymouth Mining District is located in western Amador County, California, USA, part of the Sierra Nevada foothills. It’s about 45 miles southeast of Sacramento, with elevations ranging from 250 feet to over 9,000 feet. This district includes towns like Jackson, Sutter Creek, and Amador City, all part of the famous Mother Lode region. Nearby, you’ll find other historic mining towns, adding to the area’s rich exploration history.
Minerals Produced
This district is renowned for gold, with over 140 recorded localities, but it also hosts a variety of other minerals. Highlights include uvarovite (a rare chromium-rich garnet), a 2.65-carat diamond found in 1934, and minerals like arsenopyrite, chalcopyrite, galena, sphalerite, and quartz. These minerals offer a diverse palette for collectors, formed through the region’s complex geological processes.
Geological Structure
The area’s geology features a mix of Jurassic formations, including gray to black slate (Mariposa Formation) and massive greenstone (Logtown Ridge Formation), with older Carboniferous to Permian metasedimentary rocks to the east. South of Jackson, Tertiary auriferous channel gravels—remnants of ancient rivers—also contain gold, showcasing the region’s dynamic geological history.
Mining History
Mining here started with placer gold in the mid-19th century, evolving into lode mining with iconic mines like the Kennedy (1856), Argonaut (1850), and Keystone (1853). The Kennedy Mine was notably the deepest of its time, and operations lasted nearly 90 years, leaving behind a legacy of wealth and innovation, with remnants like shafts and tailings still visible today.
Local Culture and Characteristics
Amador County is steeped in gold rush history, with Jackson settled by 1849 and named after Colonel Alden Jackson. It’s named after José María Amador, a local miner from 1848-1849. Today, alongside its mining past, the county is known for its wineries, producing fine California wines, blending old-world charm with modern viticulture.
Climate and Ecology
The region has a Mediterranean climate, with hot, dry summers and mild, wet winters. The elevation range supports diverse ecosystems, from oak woodlands to pine forests, shaped by rivers like the Cosumnes. The geology, including Tertiary gravels, reflects the area’s climatic and environmental history, influencing mineral formation.