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Snelling District

Past Producer in Merced county in California, United States with commodities Gold, Platinum, Silver
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Public Land Survey System information
  6. Commodities
  7. Materials information
  8. Mineral occurrence model information
  9. Host and associated rocks
  10. Nearby scientific data
  11. Ore body information
  12. Controls for ore emplacement
  13. Economic information about the deposit and operations
  14. Mining district
  15. Bibliographic references
  16. General comments
  17. Reporter information

Geologic information

Identification information

Deposit ID 10310680
Record type District
Current site name Snelling District

Comments on the site identification

  • This district consists of an extensive east-west-trending dredge field along the Merced River between Merced Falls and a location a few miles west of the town of Snelling.

Geographic coordinates

Geographic coordinates: -120.43847, 37.51892 (WGS84)
Location accuracy 100(meters)
Relative position The district is about 15 miles north of the city of Merced.

Site location context

Political divisions (FIPS codes)

Merced(county)

California(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Snelling(quadrangle 1:24,000 scale)

Oakdale(quadrangle 1:100,000 scale)

San Jose(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Lower San Joaquin River(hydrologic unit)

San Joaquin(hydrologic accounting unit)

San Joaquin(hydrologic subregion)

California(hydrologic region)

Geographic areas

Country State County
United States California Merced

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 005S 014E 09 N2 California

Comments on the location information

  • Location selected for latitude and longitude is the town of Snelling on the USGS 7.5-minute Snelling quadrangle.

Commodities

Commodity Importance
Gold Primary
Platinum Critical Secondary
Silver Secondary

Comments on the commodity information

  • Commodity Info: the gold varies from pin-point size to small flakes and averages about 890 in fineness. Platinum and silver are also present. Dredge recoveries ranged from $0.10 to $0.30 of gold per cubic yard with the average close to $0.10.
  • Ore Materials: Native gold, native platinum
  • Gangue Materials: Metamorphic rock, igneous rock, quartz (all as clasts)

Materials information

Materials Type of material
Gold Ore
Platinum Ore
Quartz Gangue

Mineral occurrence model information

Model code 119
USGS model code 39a
Deposit model name Placer Au-PGE
Mark3 model number 54

Host and associated rocks

  • Host or associated Host
    Rock type Unconsolidated Deposit > Sand and Gravel
    Stratigraphic age (youngest) Quaternary

Nearby scientific data

(1) -120.43847, 37.51892
ListMap

Economic information

Ore body information

  • General form Irregular

Controls for ore emplacement

  • Mechanical accumulation within stream-channel lag gravels, bars, and point-bar deposits.

Comments on the geologic information

  • REGIONAL GEOLOGY

    The Snelling District is situated within the Great Valley geologic province, which is here represented by the San Joaquin Valley. It is adjacent to the westernmost edge of the Sierra Nevada geologic province.

    The Great Valley province is characterized by Cenozoic sedimentary and volcanic rocks, while the Sierra Nevada province is characterized by complex lithologies and structures that were assembled through various plate-tectonic processes.

    In this region, the Sierra Nevada province is composed of belts of Paleozoic-Mesozoic metamorphic complexes that are intruded by various Mesozoic plutons. Together, they compose the basement of the province. This basement is overlain at higher elevations by erosional remnants of Cenozoic volcanic and sedimentary rocks, including gravels. Most of these various lithologies contain gold in places.

    Structurally, the metamorphic rocks and some of the plutonic rocks have been deformed by folding and faulting. The major fault zones typically trend northerly or northwesterly, although in places intrusion of the younger plutons has deformed some of the zones so as to assume other trends as well. In contrast, the overlying Cenozoic rocks are relatively undeformed.

    The rocks of the Great Valley province overlie the basement of the Sierra Nevada where it extends westward underneath the San Joaquin Valley.

    LOCAL GEOLOGY

    The Snelling District is associated with modern alluvial deposits of the main drainage of the Merced River where it discharges into the San Joaquin Valley after passing through the Sierra Nevada basement terranes. The materials in these deposits have been derived by erosion of the various basement and Cenozoic rocks at higher elevations. In places, the basement rocks contain gold within quartz veins and altered rock, while the Cenozoic deposits contain placer gold derived by erosion of these older basement rocks. Erosion of both the gold-bearing basement rocks and the older Cenozoic rocks provided the gold that was eventually deposited in the modern placer deposits along the main Merced River at Snelling.

Economic information about the deposit and operations

Operation type Surface
Development status Past Producer
Commodity type Metallic
Deposit size Medium
Significant Yes
Discovery year 1850

Mining district

District name Snelling District

Comments on the workings information

  • The district is composed mainly of a dredge field about nine miles long and 1/2 to 1-1/2 miles wide. Minor workings from surface placering and hydraulicking processes were also present locally.

    Vast deposits of dredge tailings still remain in this district.

Comments on other economic factors

  • Koschmann and Bergendahl (1968) reported about 516,000 ounces of gold produced from this district. Clark (1970) estimated that total production of gold for this district was approximately $17 million.

Comments on development

  • As published information about this district is sparse, it is uncertain exactly what year mining activity began in this district. Nonetheless, some surface placer mining and hydraulicking were done in the terrace deposits along the river during the gold rush. The dominant production from the district came from dredging in the 20th century. This method of mining began in 1907 and continued intermittently at least until 1952.

    Amalgamation was used in the recovery process.

Reference information

Bibliographic references

  • Deposit

    Clark, W. B., 1970, Gold districts of California: California Divisions of Mines and Geology Bulletin 193, p. 120-121.

  • Deposit

    Davis, F.F. and Carlson, D.W., 1952, Mines and mineral resources of Merced County: California Journal of Mines and Geology, v. 48, no. 3, p. 220-227.

  • Deposit

    Koschmann, A.H., and Bergendahl, M.H., 1968, Principal gold-producing districts of the United States: U. S. Geological Survey Professional Paper 610, 283 p.

  • Deposit

    Wagner, D.L., Bortugno, E.J., and McJunkin, R.D., 1990, Geologic map of the San Francisco-San Jose Quadrangle, California: California Department of Conservation, Division of Mines and Geology Regional Geologic Map Series, Map No. 5A, scale 1:250,000.

General comments

Subject category Comment text
Deposit Gold was recovered from Quaternary alluvial gravels and flood-plain and terrace deposits in and adjacent to the Merced River. The gravels are loose with very little clay and range from 18 to 36 feet in depth. The gold is distributed throughout the gravel, but the principal concentration is near the bedrock, which has a very irregular surface. Bedrock varies from slate in the vicinity of Merced Falls to Cenozoic volcanic deposits farther west.

Platinum is also present in the alluvial deposits.

Reporter information

Type Date Name Affiliation Comment
Reporter 07-AUG-2006 Higgins, Chris T. California Geological Survey CGS (Formerly CDMG)
Editor 01-SEP-2007 Schruben, Paul G. U.S. Geological Survey Converted from S&A FileMaker format to Oracle. Edit checks on rocks, units, and ages with Geolex search, and other fields.

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

Maps centered on this site

Authoritative California resources

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