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El Dorado Mining District, Mother Lode Belt, El Dorado Co., California, USAi
Regional Level Types
El Dorado Mining DistrictMining District
Mother Lode BeltBelt
El Dorado Co.County
CaliforniaState
USACountry

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Key
Latitude & Longitude (WGS84):
38° North , 120° West (est.)
Estimate based on other nearby localities or region boundaries.
Margin of Error:
~5km
Locality type:


Location and History
This district is in west-central El Dorado County a few miles southwest of Placerville. It is in the Mother Lode gold belt and includes the Logtown area a few miles to the south of El Dorado. El Dorado, originally known as Mud Springs, was a camp on the Kit Carson emigrant trail before the beginning of the gold rush. There was much activity here during the gold rush and for some years afterward. The Church, Union and other mines were worked on a large scale during the 1890's and early 1900's. There was some work in the district again in the 1930's, but only minor prospecting since. This district is to the N of the Nashville District.

Geology
Slate of the Mariposa Formation (Upper Jurassic) occurs in the central portion of the district. Massive greenstone of the Logtown Ridge Formation (Upper Jurassic) is to the west, and granite rocks, schist and amphibolite lie to the east. The Mother Lode Belt here bends from the north to the northeast towards Placerville.

Ore Deposits
Most of the quartz veins in this district are confined to the slate, although a few are in greenstone and schist. They have north to northeast strikes and usually range from five to 10 feet in thickness. The ore contains free gold and pyrite and has an average content of about Yo ounce of gold per ton. Considerable high-grade ore was recovered from shallow workings. Much fault gouge is present. The greatest depth of development is about 2,000 feet.

Mines
Bidstrup, Buena Vista, Church ($1 million), Crown Point, Crusader, German, Griffith, Larkin, Martinez, McNulty, Ophir, Pochahantas, Red Wing, Starlight, Tullis, Union ($5 million?).

Regions containing this locality

Pacific OceanOcean
North America PlateTectonic Plate

Select Mineral List Type

Standard Detailed Strunz Dana Chemical Elements

Commodity List

This is a list of exploitable or exploited mineral commodities recorded from this region.


Mineral List

Mineral list contains entries from the region specified including sub-localities

16 valid minerals.

Detailed Mineral List:

Arsenopyrite
Formula: FeAsS
Reference: Emmons and Becker (1885) Statistics and Technology of the precious Metals. Census reports Tenth census. June 1, 1880, Volume 13 By United States. Census office. 10th census, 1880, United States. Census Office
Bornite
Formula: Cu5FeS4
Calcite
Formula: CaCO3
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10310688.
Chalcopyrite
Formula: CuFeS2
Diopside
Formula: CaMgSi2O6
Colour: Dark green
Description: Occurs as fine crystals.
Reference: Hanks, Henry Garber (1884), Fourth report of the State Mineralogist: California Mining Bureau. Report 4, 410 pp. (includes catalog of minerals of California pp. 63-410), and miscellaneous observations on mineral products): 318; Kunz, George Frederick (1889), Apophyllite from California: Soc. Franc. Mineralogie, Bulletin 12: 80; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 307.
Galena
Formula: PbS
Gold
Formula: Au
Localities: Reported from at least 47 localities in this region.
Muscovite
Formula: KAl2(AlSi3O10)(OH)2
Muscovite var: Sericite
Formula: KAl2(AlSi3O10)(OH)2
'Psilomelane'
Formula: Mn, O
Pyrite
Formula: FeS2
Localities: Reported from at least 7 localities in this region.
Pyrite var: Auriferous Pyrite
Formula: FeS2
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10310688.
Pyrolusite
Formula: Mn4+O2
Pyrrhotite
Formula: Fe7S8
Reference: U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
Quartz
Formula: SiO2
Localities: Reported from at least 44 localities in this region.
Rhodonite
Formula: Mn2+SiO3
Silver
Formula: Ag
Reference: U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
Sphalerite
Formula: ZnS
Reference: Emmons and Becker (1885) Statistics and Technology of the precious Metals. Census reports Tenth census. June 1, 1880, Volume 13 By United States. Census office. 10th census, 1880, United States. Census Office
Talc
Formula: Mg3Si4O10(OH)2
Description: Occurs as talcose schist in the vein.
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10030133.

List of minerals arranged by Strunz 10th Edition classification

Group 1 - Elements
Gold1.AA.05Au
Silver1.AA.05Ag
Group 2 - Sulphides and Sulfosalts
Arsenopyrite2.EB.20FeAsS
Bornite2.BA.15Cu5FeS4
Chalcopyrite2.CB.10aCuFeS2
Galena2.CD.10PbS
Pyrite2.EB.05aFeS2
var: Auriferous Pyrite2.EB.05aFeS2
Pyrrhotite2.CC.10Fe7S8
Sphalerite2.CB.05aZnS
Group 4 - Oxides and Hydroxides
Pyrolusite4.DB.05Mn4+O2
Quartz4.DA.05SiO2
Group 5 - Nitrates and Carbonates
Calcite5.AB.05CaCO3
Group 9 - Silicates
Diopside9.DA.15CaMgSi2O6
Muscovite9.EC.15KAl2(AlSi3O10)(OH)2
var: Sericite9.EC.15KAl2(AlSi3O10)(OH)2
Rhodonite9.DK.05Mn2+SiO3
Talc9.EC.05Mg3Si4O10(OH)2
Unclassified Minerals, Rocks, etc.
'Psilomelane'-Mn, O

List of minerals arranged by Dana 8th Edition classification

Group 1 - NATIVE ELEMENTS AND ALLOYS
Metals, other than the Platinum Group
Gold1.1.1.1Au
Silver1.1.1.2Ag
Group 2 - SULFIDES
AmBnXp, with (m+n):p = 3:2
Bornite2.5.2.1Cu5FeS4
AmXp, with m:p = 1:1
Galena2.8.1.1PbS
Pyrrhotite2.8.10.1Fe7S8
Sphalerite2.8.2.1ZnS
AmBnXp, with (m+n):p = 1:1
Chalcopyrite2.9.1.1CuFeS2
AmBnXp, with (m+n):p = 1:2
Arsenopyrite2.12.4.1FeAsS
Pyrite2.12.1.1FeS2
Group 4 - SIMPLE OXIDES
AX2
Pyrolusite4.4.1.4Mn4+O2
Group 14 - ANHYDROUS NORMAL CARBONATES
A(XO3)
Calcite14.1.1.1CaCO3
Group 65 - INOSILICATES Single-Width,Unbranched Chains,(W=1)
Single-Width Unbranched Chains, W=1 with chains P=2
Diopside65.1.3a.1CaMgSi2O6
Single-Width Unbranched Chains, W=1 with chains P=5
Rhodonite65.4.1.1Mn2+SiO3
Group 71 - PHYLLOSILICATES Sheets of Six-Membered Rings
Sheets of 6-membered rings with 2:1 layers
Muscovite71.2.2a.1KAl2(AlSi3O10)(OH)2
Talc71.2.1.3Mg3Si4O10(OH)2
Group 75 - TECTOSILICATES Si Tetrahedral Frameworks
Si Tetrahedral Frameworks - SiO2 with [4] coordinated Si
Quartz75.1.3.1SiO2
Unclassified Minerals, Mixtures, etc.
Muscovite
var: Sericite
-KAl2(AlSi3O10)(OH)2
'Psilomelane'-Mn, O
Pyrite
var: Auriferous Pyrite
-FeS2

List of minerals for each chemical element

HHydrogen
H Muscovite (var: Sericite)KAl2(AlSi3O10)(OH)2
H TalcMg3Si4O10(OH)2
H MuscoviteKAl2(AlSi3O10)(OH)2
CCarbon
C CalciteCaCO3
OOxygen
O QuartzSiO2
O PsilomelaneMn, O
O PyrolusiteMn4+O2
O RhodoniteMn2+SiO3
O DiopsideCaMgSi2O6
O Muscovite (var: Sericite)KAl2(AlSi3O10)(OH)2
O CalciteCaCO3
O TalcMg3Si4O10(OH)2
O MuscoviteKAl2(AlSi3O10)(OH)2
MgMagnesium
Mg DiopsideCaMgSi2O6
Mg TalcMg3Si4O10(OH)2
AlAluminium
Al Muscovite (var: Sericite)KAl2(AlSi3O10)(OH)2
Al MuscoviteKAl2(AlSi3O10)(OH)2
SiSilicon
Si QuartzSiO2
Si RhodoniteMn2+SiO3
Si DiopsideCaMgSi2O6
Si Muscovite (var: Sericite)KAl2(AlSi3O10)(OH)2
Si TalcMg3Si4O10(OH)2
Si MuscoviteKAl2(AlSi3O10)(OH)2
SSulfur
S PyrrhotiteFe7S8
S ChalcopyriteCuFeS2
S PyriteFeS2
S BorniteCu5FeS4
S GalenaPbS
S ArsenopyriteFeAsS
S SphaleriteZnS
S Pyrite (var: Auriferous Pyrite)FeS2
KPotassium
K Muscovite (var: Sericite)KAl2(AlSi3O10)(OH)2
K MuscoviteKAl2(AlSi3O10)(OH)2
CaCalcium
Ca DiopsideCaMgSi2O6
Ca CalciteCaCO3
MnManganese
Mn PsilomelaneMn, O
Mn PyrolusiteMn4+O2
Mn RhodoniteMn2+SiO3
FeIron
Fe PyrrhotiteFe7S8
Fe ChalcopyriteCuFeS2
Fe PyriteFeS2
Fe BorniteCu5FeS4
Fe ArsenopyriteFeAsS
Fe Pyrite (var: Auriferous Pyrite)FeS2
CuCopper
Cu ChalcopyriteCuFeS2
Cu BorniteCu5FeS4
ZnZinc
Zn SphaleriteZnS
AsArsenic
As ArsenopyriteFeAsS
AgSilver
Ag SilverAg
AuGold
Au GoldAu
PbLead
Pb GalenaPbS

References

Sort by

Year (asc) Year (desc) Author (A-Z) Author (Z-A)
Lindgren, Waldemar (1894), Placerville folio: USGS Geological Atlas of the U.S., folio 3, 4 pp.
Storms, W. H. (1900), Church and Union mines: California Mining Bureau Bulletin 18: 91-92.
Tucker, W. B. (1919), El Dorado County, Church and Union mines: California Mining Bureau Report 15: 283, 299.
Logan, C. A. (1936), Mother Lode gold belt, Church and Martinez mines: California Division of Mines Bulletin 108: 21-22, 30-31.
Clark, W. B., and Carlson, D.W. (1956), EI Dorado County, lode gold mines: California Jour. Mines and Geology, vol. 52, pp. 401-429.
Lindgren, Waldemar & Henry Ward Turner (1894), Description of the gold belt, California; description of the Placerville sheet: USGS Geol. Atlas, Placerville folio (Folio No. 3) 3 pp.; […(abstract): Jour. Geol.: 4: 248-250 (1896)].
Storms, William H. (1900), The Mother Lode region of California: Church and Union Mines, California Mining Bureau. Bulletin 18: 91-92.
Tucker, W. Burling & C.A. Waring (1919), El Dorado County: California Journal of Mines and Geology, California Mining Bureau. (Report 15): 15: 283, 299.
Logan, Clarence August (1935), Mother Lode Gold Belt of California: California, Church and Martinez Mines, Division Mines Bulletin 108, 221 pp.: 21-22, 30-31.
Clark, Wm. B. & D.W. Carlson (1956), Mines and mineral resources of El Dorado County, California: California Journal of Mines and Geology: 52(4): 401-429.
Clark, Wm. B. (1970a) Gold districts of California: California Division Mines & Geology Bulletin 193: 45.

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