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Angels Camp Mining District, Mother Lode Belt, Calaveras Co., California, USAi
Regional Level Types
Angels Camp Mining DistrictMining District
Mother Lode BeltBelt
Calaveras 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
This district is in southwest Calaveras County in the vicinity of the town of Angels Camp and Altaville. It is an important part of the Mother Lode belt and lies between the San Andreas district to the northwest and the Carson Hill district to the southeast. It is both a lode and placer district, but the lode mines have been more productive.

History
The streams in the area were mined shortly after the beginning of the gold rush. The town was founded in 1848 and named for Henry Angel, who had established a trading post here. Rich surface ores were mined in the oxidized zones in the 1850s, and most of the important veins were discovered at that time. By 1885 Angels Camp had become one of the major gold-mining districts in the state. The Utica Mining Company was organized in the middle 1850s, and for the next 40 years the Utica mine was a major source of gold. From 1893 to 1895 this mine yielded more than $4 million worth of gold. All of the major mines were shut down during World War I. There was some activity in the district again during the 1930's, and the Calaveras Central and Altaville drift mines have been intermittently prospected during the past 15 years. This district has an estimated total output of at least $30 million, and it may be considerably more. The colorful jumping frog jubilee held each year at nearby Frogtown, the county fairgrounds, is based on Mark Twain's tale, The Jumping Frog of Calaveras County. He is supposed to have first related the story at the Angels Hotel.

Geology
This district is underlain by a series of northwest-striking beds of amphibolite and chlorite schist, phyllite, greenstone, and metagabbro. To the east and west are slate, impure quartzite, and micaceous schist. In the north and northeast part of the district is the west and northwest-trending Tertiary Central channel, which is a tributary of the ancestral Calaveras River. The channel gravels are cemented, contain abundant quartz, and are overlain by rhyolite tuff and andesite.

The geology of the Angels Camp district is complex. Bedrock, which is assigned either to the Calaveras Complex or unnamed units of Jurassic age, consists of a series of northwest-striking beds of amphibolite and chlorite schists, phyllite, greenstone, and metagabbro. Ore deposits occur either in amphibolite and chlorite schist or phyllite. There are three principal northwest striking vein systems in the district. In the westernmost system, the veins are in phyllite. In the center system, the veins are along the western margin of a northwest trending belt of metagabbro. In the eastern system, which includes the Lightner Mine, the ore deposits occur in amphibolite and greenstone. To the east and west of the district, bedrock is composed of slate, impure quartzite, and micaceous schist (Clark, 1970).
The low-grade ore bodies in the Lightner and adjoining Utica mine are not within simple gold-quartz veins like many Mother Lode deposits, but instead consist of numerous lenticular quartz-calcite stringer veins separated by various thicknesses of mineralized fissured amphibolite and chloritic and talcose schist. Nonetheless, the mineralized zone was designated the Utica vein (or Bonanza vein) in mine records. Geologically, the Lightner Mine is an extension of the ore body developed in the larger neighboring Utica Mine. In the Lightner Mine, the Utica vein ranged from 10 to 120 feet thick (Storms, 1900; Clark and Lydon, 1962).

Specific information regarding the nature of the ore in the Lightner Mine is meager. However, several records cite its similarity to ore in the adjoining Utica Mine for which there is considerably more information, and from which this description is largely drawn. The stringers range from a few inches to three feet thick and are largely quartz, but carbonate is abundant, especially in the smaller fissures. The stringers strike about N 50? W and dip steeply northeast to vertical, lying nearly in the planes of schistosity of the country rock (Eisenhauer, 1932). Both the quartz and nearby country rock contain free gold and auriferous pyrite. The schist is greatly altered and pyritized and carries the greater gold values. The schists are largely altered and compose of ankerite and sericite, with subordinate quartz, albite, and pyrite.

The richest ore was called "brown quartz", consisting of a fine granular aggregate of quartz, dolomite, and sometimes albite, with abundant small crystals of pyrite. The brown quartz does not always form well-defined veins or stringers, but is intimately associated with the country rock, and is in part an altered form of the country rock. The other vein minerals are free gold, sericite, and chalcopyrite. Gold is not visible in most of the ore, but occurs in considerable masses in certain rich streaks (Ransome, 1900).

The rich brown quartz ore was confined to the shallow workings above the 600-foot level and where the ore body was 120 feet wide. Between the 500 and 600-foot levels the ore body was cut off by a zone of talc 15 to 20 feet thick with a dip of 30? NE (Tucker, 1916). This truncation and a similar talc zone were encountered within the Utica vein in the adjoining Utica Mine where Eisenhauer (1932) and McCurdy (1932) interpreted the abrupt flooring of the ore body to a reverse fault plane within the talc zone, above which the best ore occurred in the hanging wall. The ore body is said to have been picked up below the talc zone in a crosscut run 150 feet on the 900-foot level, but its dip had steepened to between 80?E and vertical (from 65?-71? above the talc) and the ore body had split into three distinctive vein zones, separated by barren schist about 100 feet north of the shaft (Clark and Lydon, 1962).

The grade of ore varied greatly. Information about the ore body in the Utica Mine indicates the shallowest ores yielded as much as $13.02 per ton but declined to $3.60 or less with depth. Occasionally small high-grade pockets were found. Pyrite and chalcopyrite are the only sulfides reported in the ore. Ore averaged about 2% concentrates.

Ore Deposits
The lode deposits consist of massive quartz veins, zones of parallel quartz stringers and bodies of mineralized schist and greenstone. The ore contains disseminated free gold and auriferous pyrite. Usually the gold is in fine particles, although occasional high-grade pockets containing coarse gold have been found. Calcite, talc, ankerite, and sericite, are commonly present in the ore. The milling-grade ore usually averaged 1/7 to 1/5 ounce of gold per ton, but the ore bodies were scores of feet in thickness, hundreds of feet in length, and were mined to depths of several thousand feet.

The deposits occur either in the amphibolite and chlorite schist or phyllite. There are three principal vein systems. In the system on the west the veins are in phyllite. In the center one the veins are along the west margin of a northwest-trending belt of metagabbro. In the eastern system, which contains the famous Utica mine, the ore deposits are in amphibolite and greenstone.

Mines
Lode: Altaville, Angels $3.25 million+, Angels Deep $100,000+, Belmont-Osborn $100,000+, Benson, Big Spring, Bruner, Bullion, Chaparral Hill, Cherokee, Evening Star, Ghost, Gold Cliff $2,834,- 000+, Gold Hill $100,000+, Great Western, Hardy, Keystone, Last Chance, Lightner $3 million+, Lindsey, Madison $1 million+, Marble Springs, Mohawk, Mother Lode Central $100,000+, Oriole, Parnell, Pure Quill, Santa Ana, Sultana $200,000+, Tollgate, Triple Lode, Tulloch, Utica $17 million, Vonich, Whittle, Wagon Rut, Waterman, Yellowstone. Drift: Altaville, Calaveras Central 22,000 ounces+.

Regions containing this locality

Pacific OceanOcean
North America PlateTectonic Plate

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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

20 valid minerals.

Rock Types Recorded

Note: this is a very new system on mindat.org and data is currently VERY limited. Please bear with us while we work towards adding this information!

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

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Alphabetical List Tree Diagram

Detailed Mineral List:

Albite
Formula: Na(AlSi3O8)
Altaite
Formula: PbTe
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): 68; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 61, 116, 286; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 105, 110.
'Amphibole Supergroup'
Formula: AX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
Description: Occurs as amphibole schist both in and out of the veins.
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10102716.
Ankerite
Formula: Ca(Fe2+,Mg)(CO3)2
Localities:
Arsenopyrite
Formula: FeAsS
Reference: Clark, Wm. B. & P.A. Lydon (1962), Mines and mineral resources of Calaveras County, California: California Division of Mines & Geology County Report 2; [… Geological Society of America Proceedings, 1933: 312-313, 1934]: 71; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 75.
Calaverite
Formula: AuTe2
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): 68; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 116; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 110.
Calcite
Formula: CaCO3
Localities: Reported from at least 7 localities in this region.
Chalcocite
Formula: Cu2S
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10029117.
Chalcopyrite
Formula: CuFeS2
'Chlorite Group'
Dolomite
Formula: CaMg(CO3)2
Galena
Formula: PbS
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
Gold
Formula: Au
Localities: Reported from at least 110 localities in this region.
Gypsum
Formula: CaSO4 · 2H2O
Description: Occurs as platy aggregates with quartz.
Reference: Knopf, Adolf (1929), The Mother Lode system of California: USGS Professional Paper 157, 88 pp.: 37; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 285.
Margarite
Formula: CaAl2(Al2Si2O10)(OH)2
Reference: Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 255; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 431.
Molybdenite
Formula: MoS2
Description: Occurs in sulphide-rich Au ore.
Reference: Brown, J.A. (1890), Amador, Calaveras Counties: California Mining Bureau. Report 10: 98-123, 147-152; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 79.
Muscovite
Formula: KAl2(AlSi3O10)(OH)2
Muscovite var: Sericite
Formula: KAl2(AlSi3O10)(OH)2
Petzite
Formula: Ag3AuTe2
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): 68; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 116, 286; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 110.
'Psilomelane'
Formula: Mn, O
Colour: Blue-black
Description: Hard material with flesh-colored chert.
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10028967.
Pyrite
Formula: FeS2
Localities: Reported from at least 12 localities in this region.
Quartz
Formula: SiO2
Localities: Reported from at least 83 localities in this region.
Silver
Formula: Ag
Reference: U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
Talc
Formula: Mg3Si4O10(OH)2
Localities: Reported from at least 7 localities in this region.

List of minerals arranged by Strunz 10th Edition classification

Group 1 - Elements
Gold1.AA.05Au
Silver1.AA.05Ag
Group 2 - Sulphides and Sulfosalts
Altaite2.CD.10PbTe
Arsenopyrite2.EB.20FeAsS
Calaverite2.EA.10AuTe2
Chalcocite2.BA.05Cu2S
Chalcopyrite2.CB.10aCuFeS2
Galena2.CD.10PbS
Molybdenite2.EA.30MoS2
Petzite2.BA.75Ag3AuTe2
Pyrite2.EB.05aFeS2
Group 4 - Oxides and Hydroxides
Quartz4.DA.05SiO2
Group 5 - Nitrates and Carbonates
Ankerite5.AB.10Ca(Fe2+,Mg)(CO3)2
Calcite5.AB.05CaCO3
Dolomite5.AB.10CaMg(CO3)2
Group 7 - Sulphates, Chromates, Molybdates and Tungstates
Gypsum7.CD.40CaSO4 · 2H2O
Group 9 - Silicates
Albite9.FA.35Na(AlSi3O8)
Margarite9.EC.30CaAl2(Al2Si2O10)(OH)2
Muscovite9.EC.15KAl2(AlSi3O10)(OH)2
var: Sericite9.EC.15KAl2(AlSi3O10)(OH)2
Talc9.EC.05Mg3Si4O10(OH)2
Unclassified Minerals, Rocks, etc.
'Amphibole Supergroup'-AX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
'Chlorite Group'-
'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 = 2:1
Chalcocite2.4.7.1Cu2S
Petzite2.4.3.3Ag3AuTe2
AmXp, with m:p = 1:1
Altaite2.8.1.3PbTe
Galena2.8.1.1PbS
AmBnXp, with (m+n):p = 1:1
Chalcopyrite2.9.1.1CuFeS2
AmBnXp, with (m+n):p = 1:2
Arsenopyrite2.12.4.1FeAsS
Calaverite2.12.13.2AuTe2
Molybdenite2.12.10.1MoS2
Pyrite2.12.1.1FeS2
Group 14 - ANHYDROUS NORMAL CARBONATES
A(XO3)
Calcite14.1.1.1CaCO3
AB(XO3)2
Ankerite14.2.1.2Ca(Fe2+,Mg)(CO3)2
Dolomite14.2.1.1CaMg(CO3)2
Group 29 - HYDRATED ACID AND NORMAL SULFATES
AXO4·xH2O
Gypsum29.6.3.1CaSO4 · 2H2O
Group 71 - PHYLLOSILICATES Sheets of Six-Membered Rings
Sheets of 6-membered rings with 2:1 layers
Margarite71.2.2c.1CaAl2(Al2Si2O10)(OH)2
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
Group 76 - TECTOSILICATES Al-Si Framework
Al-Si Framework with Al-Si frameworks
Albite76.1.3.1Na(AlSi3O8)
Unclassified Minerals, Mixtures, etc.
'Amphibole Supergroup'-AX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
'Chlorite Group'-
Muscovite
var: Sericite
-KAl2(AlSi3O10)(OH)2
'Psilomelane'-Mn, O

List of minerals for each chemical element

HHydrogen
H Muscovite (var: Sericite)KAl2(AlSi3O10)(OH)2
H TalcMg3Si4O10(OH)2
H MargariteCaAl2(Al2Si2O10)(OH)2
H GypsumCaSO4 · 2H2O
H Amphibole SupergroupAX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
H MuscoviteKAl2(AlSi3O10)(OH)2
CCarbon
C DolomiteCaMg(CO3)2
C CalciteCaCO3
C AnkeriteCa(Fe2+,Mg)(CO3)2
OOxygen
O QuartzSiO2
O AlbiteNa(AlSi3O8)
O DolomiteCaMg(CO3)2
O CalciteCaCO3
O Muscovite (var: Sericite)KAl2(AlSi3O10)(OH)2
O PsilomelaneMn, O
O TalcMg3Si4O10(OH)2
O AnkeriteCa(Fe2+,Mg)(CO3)2
O MargariteCaAl2(Al2Si2O10)(OH)2
O GypsumCaSO4 · 2H2O
O Amphibole SupergroupAX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
O MuscoviteKAl2(AlSi3O10)(OH)2
FFluorine
F Amphibole SupergroupAX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
NaSodium
Na AlbiteNa(AlSi3O8)
MgMagnesium
Mg DolomiteCaMg(CO3)2
Mg TalcMg3Si4O10(OH)2
Mg AnkeriteCa(Fe2+,Mg)(CO3)2
AlAluminium
Al AlbiteNa(AlSi3O8)
Al Muscovite (var: Sericite)KAl2(AlSi3O10)(OH)2
Al MargariteCaAl2(Al2Si2O10)(OH)2
Al Amphibole SupergroupAX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
Al MuscoviteKAl2(AlSi3O10)(OH)2
SiSilicon
Si QuartzSiO2
Si AlbiteNa(AlSi3O8)
Si Muscovite (var: Sericite)KAl2(AlSi3O10)(OH)2
Si TalcMg3Si4O10(OH)2
Si MargariteCaAl2(Al2Si2O10)(OH)2
Si Amphibole SupergroupAX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
Si MuscoviteKAl2(AlSi3O10)(OH)2
SSulfur
S MolybdeniteMoS2
S PyriteFeS2
S ChalcopyriteCuFeS2
S ArsenopyriteFeAsS
S GypsumCaSO4 · 2H2O
S GalenaPbS
S ChalcociteCu2S
ClChlorine
Cl Amphibole SupergroupAX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
KPotassium
K Muscovite (var: Sericite)KAl2(AlSi3O10)(OH)2
K MuscoviteKAl2(AlSi3O10)(OH)2
CaCalcium
Ca DolomiteCaMg(CO3)2
Ca CalciteCaCO3
Ca AnkeriteCa(Fe2+,Mg)(CO3)2
Ca MargariteCaAl2(Al2Si2O10)(OH)2
Ca GypsumCaSO4 · 2H2O
TiTitanium
Ti Amphibole SupergroupAX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
MnManganese
Mn PsilomelaneMn, O
FeIron
Fe PyriteFeS2
Fe ChalcopyriteCuFeS2
Fe AnkeriteCa(Fe2+,Mg)(CO3)2
Fe ArsenopyriteFeAsS
CuCopper
Cu ChalcopyriteCuFeS2
Cu ChalcociteCu2S
AsArsenic
As ArsenopyriteFeAsS
MoMolybdenum
Mo MolybdeniteMoS2
AgSilver
Ag SilverAg
Ag PetziteAg3AuTe2
TeTellurium
Te AltaitePbTe
Te CalaveriteAuTe2
Te PetziteAg3AuTe2
AuGold
Au GoldAu
Au CalaveriteAuTe2
Au PetziteAg3AuTe2
PbLead
Pb AltaitePbTe
Pb GalenaPbS

References

Sort by

Year (asc) Year (desc) Author (A-Z) Author (Z-A)
Fairbanks, H.W., (1890), Geology of the Mother Lode region: California Mining Bureau (Report 10): 10: 59-62.
Crawford, J.J. (1894), Utica Stickles mine: California Mining Bureau (Report 12): 12: 98-99.
Turner, H.W. (1894), Jackson folio, California: USGS Geologic Atlas of the U.S., folio No. 11, 6 pp.
Ransome, F.L. (1900), Mother Lode district folio, California: USGS Geologic Atlas of the U.S., folio No. 163, 11 pp.
Storms, W.H. (1900), The Mother lode region-Calaveras County: California Mining Bureau Bulletin IB: 100-127.
Tucker, W.B. (1916), Calaveras County, Angels, Gold Cliff, Lightner, and Utica Mines. California Mining Bureau (Report 14): 14: 68-69, 81-82, 89-90, 110-112.
Knopf, Adolph (1929), Gold Cliff Mine: USGS Professional Paper 157: 71-72.
Logan, C.A. (1935), Mother Lode gold belt-Calaveras County: California Division of Mines Bulletin 108: 125-152.
Julihn, C.E., and Horton, F.W. (1938), Mines of the southern Mother Lode Region: U.S. Bureau of Mines Bulletin 413: 21-94.
Averill, C.V. (1946), Placer mining for gold in California: California State Division of Mines and Geology Bulletin 135, 336 p.: 235-247.
Eric, J.H., A.A. Stromquist & C.M. Swinney (1955), Geology and mineral deposits of the Angels Camp and Sonora quadrangles, Calaveras and Tuolumne Counties, California: California Division Mines Special Report 41, 55 pp.
Clark, W.B., and Lydon, P.A. (1962), Calaveras County, gold: California Division of Mines and Geology, County Report 2: 32-93.

Localities in this Region


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