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Aspen District

Past Producer in Pitkin county in Colorado, United States with commodities Silver, Lead, Zinc, Copper, Gold, Manganese, Cadmium, Uranium, Arsenic, Antimony, Platinum
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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. Alteration
  9. Mineral occurrence model information
  10. Host and associated rocks
  11. Nearby scientific data
  12. Geologic structures
  13. Ore body information
  14. Controls for ore emplacement
  15. Economic information about the deposit and operations
  16. Mining district
  17. Land status
  18. Workings at the site
  19. Links to other databases
  20. Bibliographic references
  21. General comments
  22. Reporter information

Geologic information

Identification information

Deposit ID 10013878
MRDS ID D010418
Record type District
Current site name Aspen District
Alternate or previous names Roaring Fork District

Geographic coordinates

Geographic coordinates: -106.82201, 39.17443 (WGS84)
Elevation 2682
Relative position 5.2 MILES N 45 E OF ASPEN, THRU ASPEN, TO 5 MILES DUE SOUTH OF ASPEN

Site location context

Political divisions (FIPS codes)

Pitkin(county)

Colorado(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Aspen(quadrangle 1:24,000 scale)

Leadville(quadrangle 1:100,000 scale)

Leadville(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Roaring Fork(hydrologic unit)

Colorado Headwaters(hydrologic accounting unit)

Colorado Headwaters(hydrologic subregion)

Upper Colorado(hydrologic region)

Federal lands

White River National Forest(National Forest)

National Forest FS(Type of land area)

FS(Federal land areas administered by FS)

Geographic areas

Country State County
United States Colorado Pitkin

Public Land Survey System information

Meridian Township Range Section Fraction State
6th Principal 010S;010S;011S;011S 084W;085W;084W;085W 04,05,07,08,17,18,19,30,31;12,13,23,24,25,26,36;06,07,08,18;01,12,13 Colorado

Comments on the location information

  • ASPEN DISTRICT PROPER LIES FROM 1.5 MILES NE OF TOWN (TO HUNTER CREEK) ACROSS ROARING FORK RIVER TO TOURTELLOTTE PARK 2.5 MILES SOUTH OF TOWN. ON BASIS OF STRATIGRAPHIC/STRUCTURAL CONTINUITY AND SIMILARITY OF ORE OCCURRENCE, TOTAL ASPEN DISTRICT INCLUDES SUBDISTRICTS, SATELLITE DISTRICTS, OR AREAS OF LENADO (ON WOODY CREEK) AND RICHMOND HILL (SOUTH OF TOURTELLOTTE PARK). S-T-R DESIGNATIONS BASED ON MINING CLAIMS MAPS AND ON PROJECTIONS INTO UNSURVEYED AREA AROUND ASPEN. DISTRICT ALSO INCLUDES T9S, R84W (SECS. 03, 10, 15, 22, 27, 28, 33, 34) (LENADO AREA) AND EXTENDS ONTO HAYDEN PEAK AND RUEDI QUADRANGLES. LAT-LONG GIVEN IS CENTER OF COMMON LINE OF T10S, R 84 & 85W. ; INFO FROM LAND.ST :(1980)

Commodities

Commodity Importance
Silver Primary
Lead Primary
Zinc Critical Primary
Copper Secondary
Gold Secondary
Manganese Critical Tertiary
Cadmium Tertiary
Uranium Tertiary
Arsenic Critical Tertiary
Antimony Critical Tertiary
Platinum Critical Tertiary

Comments on the commodity information

  • BASTIN (1925) REPORTED OCCURRENCE OF PYRITE, CHALCOCITE, AND COVELLITE AS RARE. MOST AU IN DISTRICT APPARENTLY OCCURRED IN PLACERS; IN LODE DEPOSITS, OCCURRENCE AS NATIVE AU OR CONTAINMENT IN OTHER SULFIDES IS UNKNOWN. SB AND AS CONTAINED IN TETRAHEDRITE-TENNANTITE AND POLYBASITE-PEARCEITE. CD ASSOCIATED WITH ZINC PROBABLY IN SPHALERITE (BRYANT, 1979), BUT SPURR (1898) REPORTS OCCURRENCE OF SMALL AMOUNTS OF CD, AS, PB, ZN, CU, CO, AND NI IN PYRITE. VOLIN AND HILD (1950) REPORT OCCURRENCE OF WURTZITE IN SMUGGLER MINE.

Materials information

Materials Type of material
Anglesite Ore
Argentite Ore
Bornite Ore
Chalcocite Ore
Chalcopyrite Ore
Chrysocolla Ore
Covellite Ore
Cuprite Ore
Hemimorphite Ore
Malachite Ore
Polybasite Ore
Pyrargyrite Ore
Pyrite Ore
Smithsonite Ore
Sphalerite Ore
Tenorite Ore
Tetrahedrite Ore
Wurtzite Ore
Barite Gangue
Calcite Gangue
Dolomite Gangue
Epsomite Gangue
Hematite Gangue
Limonite Gangue
Quartz Gangue
Selenite Gangue
Siderite Gangue
Wad Gangue

Alteration

  • (Local) See Comments

Analytical data

Result SPURR'S (1898) AVERAGES OF ABOUT 400 ORE-SHIPMENT ASSAYS ARRANGED BY 200-FT ELEVATION INTERVALS. VALUES FOR EACH LEVEL REPRESENT ORES FROM INTERVAL +/- 100 FT OF ELEVATION. EACH SET OF VALUES IS ELEVATION (FT), OZ/TON AG, % PB, % S, % ZN, % BARITE, % FE203, % CAO, % SIO2 (NR=NOT REPORTED): 7400, 460.0, 17.5, NR, 2.4, 12.6, 1.8, 13.1, 23.2
Result 7600, 234.6, 5.6, 2.6, 2.6, 13.3, 2.7, 17.3, 19.7
Result 7800, 39.5, 16.3, 3.5, 1.9, 20.8, 4.3, 13.2, 9.2
Result 8000, 59.3, 1.8, 5.2, 1.8, 25.6, 5.5, 17.5, 17.4
Result 8200, 56.6, 2.1, 5.2, 3.2, 14.5, 4.5, 10.3, 9.9
Result 8400, 25.3, 3.8, 1.0, 1.5, 3.5, 2.4, 28.4, 10.1
Result 8600, 52.0, 2.4, 3.0, 1.0, 2.0, 3.3, 28.3, 12.8
Result 8800, 36.5, 10.8, 1.8, 1.3, 11.9, 6.4, 23.5, 17.1
Result 9000, 26.5, 4.5, 0.7, 0.4, 1.3, 4.5, 23.8, 10.3
Result 9200, 51.3, 10.4, NR, 3.5, 5.5, 6.2, 21.4, 19.8
Result 9400, 26.0, 3.0, 5.7, 3.7, 7.8, 6.4, 12.7, 33.1
Result 9600, 49.8, 2.9, 3.5, 1.9, 23.7, 10.1, 8.7, 22.6
Result 9800, 71.9, 0.8, 2.1, 1.4, 23.2, 6.5, 10.8, 32.8
Result 10000, 51.0, 4.4, 0.8, 2.1, 24.2, 8.9, 11.1, 23.0
Result 10200, 35.6, 2, 0.9, 1.5, 16.4, 4.9, 14.8, 37.6
Result 10400, 62.5, 6.7, 6.6, 3.2, 21.8, 10.3, 7.5, 27.3
Result 10600, 27.3, NR, NR, NR, 30.5, NR, NR, 52.5
Result 10800, 36.7, 6.0, 1.0, TRACE, 31.0, 4.4, 12.8, 28.5

Mineral occurrence model information

Model code 72
USGS model code 19a
Deposit model name Polymetallic replacement
Mark3 model number 47

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock > Diorite
    Stratigraphic age (youngest) Oligocene
  • Host or associated Associated
    Rock type Metamorphic Rock > Metasedimentary Rock > Quartzite
    Rock unit name Granodiorite;Hornblende Quartz Diorite, Quartz Porphyry, Aplite, And Aplite Porphyry
    Rock description Granodiorite;Hornblende Quartz Diorite, Quartz Porphyry, Aplite, And Aplite Porphyry
  • Host or associated Associated
    Rock type Plutonic Rock > Granitoid > Granite
  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Shale
  • Host or associated Host
    Rock type Sedimentary Rock > Carbonate > Limestone
  • Host or associated Host
    Rock type Sedimentary Rock > Carbonate > Dolomite
    Rock unit name Leadville Limestone (Redcliff And Castle Butte Members);Belden Formation
    Rock description Leadville Limestone (Redcliff And Castle Butte Members);Belden Formation

Nearby scientific data

(1) -106.82201, 39.17443
ListMap

Economic information

Geologic structures

Type of structure Regional
Structure description Sawatch Uplift, Central Colorado Trough, Piceance Basin, White River Uplift, Elk Uplift
Type of structure Local
Structure description Aspen Mountain Syncline, Castle Creek Fault Zone, Silver Fault, Contact Fault, Aspen Mountain Fault System, Della Fault System, Tourtellotte Park Fault System, Butte Fault System, Lenado Fault

Ore body information

  • General form IRREGULAR
  • General form IRREGULAR
  • General form IRREGULAR

Controls for ore emplacement

  • Breccia Zones Around Intersection Of Silver And Contact Bedding Plane Faults With Later Cross Faults; Paleokarst Breccia Zones Along Contact Between Leadville Limestone Members And Between Leadville And Belden Fm.; Fissures Involving Quartz Porphyry And Aplite Porphyry Sills In Belden Fm.

Comments on the geologic information

  • SEQUENCE OF STRUCTURAL DEFORMATION INTERPRETED AS (OLDEST TO YOUNGEST): 1) INITIAL UNFOLDING OF SAWATCH RANGE; 2) PROBABLE CONTEMPORANEOUS BEDDING PLANE FAULTS IN LEADVILLE LIMESTONE (SILVER AND CONTACT FAULTS); 3) START OF NORTH-SOUTH-TRENDING FAULT SYSTEMS, BEGINNING WITH CASTLE CREEK FAULT ZONE (INCLUDING CASTLE CREEK, ANNIE, AND DUBUQUE FAULTS); 4) AFTER THIS OR AT SAME TIME CAME DOMAL FOLDING IN TOURTELLOTTE PARK AREA AND FORMATION OF ASSOCIATED NORTH-SOUTH AND EAST-WEST FRACTURING; 5) FORMATION OF ASPEN MOUNTAIN FAULT SYSTEM (NORTH-SOUTH TRENDS, INCLUDING PRIDE, SADDLE ROCK, SARA JANE, SCHILLER, AND MARY B. FAULTS), MINOR CROSS-FAULTING (EAST-WEST TRENDS, INCLUDING BONNYBEL AND CHLORIDE FAULTS), DELLA FAULT SYSTEM (EAST-WEST); 6) FORMATION OF TOURTELLOTTE PARK FAULT SYSTEM (NORTH-SOUTH TRENDS, INCLUDING JUSTICE, COPPER, AND ONTARIO FAULTS); 7) FORMATION OF BUTTE FAULT SYSTEM (EAST-WEST TRENDS, INCLUDING BUTTE, GOOD THUNDER, HALLET, DIXON, SILVER BELL, BURRO, GRAND DUKE, AND
  • WINNIE FAULTS). STAGES 6 AND 7 ARE POST-MINERAL. ALTHO NO DIRECT AGES HAVE BEEN DETERMINED ON ASPEN ORES, THEIR SPATIAL ASSOCIATION SUGGESTS LARAMIDE AGE. AGES CAN BE BRACKETED BY THOSE DETERMINED ON ASSOCIATED IGNEOUS ROCKS, THE CRETACEOUS-PALEOCENE QUARTZ PORPHYRY AND APLITE (72.2 +/- 2.2 TO 67.4 +/- 2.2) AND THE LATER OLIGOCENE GRANODIORITE (33.9 +/- 1.0).

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic
Deposit size Small
Significant Yes
Discovery year 1879
Year of first production 1882
Year of last production 1968

Mining district

District name Aspen (Roaring Fork) District

Land status

Ownership category Private

Comments on the production information

  • PARTIAL PRODUCTION RECORD; FIGURES PRIOR TO 1932 NOT REPORTED SEPARATELY BY DISTRICT WITHIN PITKIN COUNTY. NO PRODUCTION REPORTED FOR 1955 OR AFTER 1956.

Comments on the reserve resource information

  • AG-PB-ZN RESERVES VERY LIKELY REMAIN IN A NUMBER OF MINES IN THE DISTRICT, BUT THEIR REOPENING AND OPERATION IS PROBABLY SEVERELY LIMITED IN MOST PLACES BY PRESENT EXTENT OF RECREATIONAL FACILITIES. HEYL (1964) STATES THAT VERY LARGE QUANTITIES OF AG-BEARING OXIDIZED ZN-PB ORES REMAIN IN DISTRICT BECAUSE AFTER RICHER ORES WERE MINED OUT BY SELECTIVE AND IRREGULAR STOPING (AS IN SMUGGLER, MOLLIE GIBSON, AND GREAT WESTERN MINES), LEANER MATERIALS WERE WASTED ONTO DUMPS. REMAINING LARGE DUMPS CONTAIN ESTIMATED 1 TO 3 % COMBINED ZN-PB, 1 TO 4 OZ/TON AG, SOME MN, MUCH IN FORM OF OXIDIZED ORE. A FEW RICHER DUMPS, PROBABLY EXCEEDING 500,000 TONS, CONTAIN ESTIMATED 5 % COMBINED PB-ZN AND 1 TO 5 OZ/TON AG. AS OF 1056, A FEW SMALL REMAINING RICH DUMPS CONTAINED 8 TO 19 % COMBINED ZN AND PB. TOURTELLOTTE PARK MAY CONTAIN A LARGE TONNAGE OF LEAN ZN-BEARING MANGANIFEROUS DOLOMITE AND MN OXIDES.

Workings at the site

  • Type of workings Underground
    Length 48279M
    Overall depth 365.76M

Comments on the workings information

  • PRINCIPAL MINES DEVELOPED BY VERTICAL SHAFTS WITH CROSSCUTS TO SILVER AND CONTACT FAULTS. SOME DECLINES ALONG FAULT PLANES. LEVELS DEVELOPED NORTH-SOUTH AND NE-SW ALONG FAULTS. CONSIDERABLE INTERCONNECTING BETWEEN PROPERTIES. LONGER DRAINAGE AND DEVELOPMENT TUNNELS DRIVEN EASTWARD TO SOUTHWARD INTO HILLSIDES WEST, NW, AND BELOW SHAFT SITES

Comments on development

  • TUNNEL, TENCHING IN ANNIE BASIN, AND CORE DRILLING IN LENADO AREA. SMUGGLER MINE CURRENTLY (1982) UNDER LEASE. DISTRICT IS NOTED AS ONE OF FIRST TO USE ELECTRIC HOISTS AND PUMPS AND AS FIRST COLORADO DISTRICT TO PRODUCE ZN FROM OXIDIZED ORE. IN 1894, SMUGGLER MINE YIELDED AG NUGGET WEIGHING 1840 LB.
  • PROSPECTORS MOVED WESTWARD FROM LEADVILLE AND MADE FIRST DISCOVERIES AROUND ASPEN IN 1879, STAKING THE SMUGGLER, DURANT, IRON, SPAR, MONARCH, AND LATE ACQUISITION CLAIMS. FIRST PRODUCTION CAME IN EARLY 1880'S FROM SPAR AND CHLORIDE MINES ON ASPEN MTN. ALTHOUGH RICH DEEPER ORES WERE FOUND BY 1884, SIGNIFICANT DEVELOPMENT NOT SEEN UNTIL ARRIVAL OF COLORADO MIDLAND RR. IN 1887. ACTIVITY ALSO SLOWED IN MID 1880'S BY LITIGATION REGARDING APEX VS VERTICAL SIDELINE METHODS OF GRANTING MINING CLAIM TITLES. DECISIONS FAVORED APEX CLAIMANTS. BOOM PERIOD FOR AG PRODUCTION WAS 1888-1892, BUT RICH ORE DEPLETION AND AG DEVALUATION IN 1893 CAUSED SUDDEN, THEN GRADUAL DECLINE TO 1903. THEN RECOVERY OF AG-BEARING ZN ORES BEGAN. BOOM IN ZN ENDED BY 1908, BUT OXIDIZED ZN AND ZN-PB ORES WERE PRODUCED SPORADICALLY FROM 1911-1929 AND 1934-1952. VERY LITTLE AG-PB-ZN PRODUCED SINCE 1952. MOST RECENT ACTIVITY WAS 1960'S AND INCLUDED ATTEMPT TO MILL SMUGGLER/MOLLIE GIBSON DUMP ORES, EXTENSION OF HIGHLAND

Reference information

Bibliographic references

  • Deposit

    BASTIN, E.S., 1924, OBSERVATIONS ON THE RICH SILVER ORES OF ASPEN, COLORADO: USGS BULL. 750, P. 41-62.

  • Deposit

    BRYANT, BRUCE, 1972, MAP SHOWING MINES, PROSPECTS, AND AREAS OF SIGNIFICANT SILVER, LEAD, AND ZINC PRODUCTION IN THE ASPEN QUADRANGLE, PITKIN COUNTY, COLORADO: USGS MAP I-785-D.

  • Deposit

    BRYANT, BRUCE, 1971, GEOLOGIC MAP OF THE ASPEN QUADRANGLE, PITKIN COUNTY, COLORADO: USGS MAP GQ-933.

  • Deposit

    BRYANT, BRUCE 1977, MINING AT ASPEN, IN VEAL, H.K., ED., EXPLORATION FRONTIERS OF THE CENTRAL AND SOUTHERN ROCKIES: RMAG SYMP. GUIDEBOOK, P. 451-456. & &

  • Deposit

    BRYANT, BRUCE 1979, GEOLOGY OF THE ASPEN 15-MINUTE QUADRANGLE, PITKIN AND GUNNISON COUNTIES, COLORADO: USGS PROF. PAPER 1073, 146 P. & &

  • Deposit

    BRYANT, BRUCE, AND FREEMAN, V.L., 1977, GEOLOGIC SUMMARY OF THE ASOEN AREA, SOUTHERN ROCKY MOUNTAINS, COLORADO, IN VEAL, H.K., ED., EXPLORATION FRONTIERS OF THE CENTRAL AND SOUTHERN ROCKIES: RMAG SYMP. GUIDEBOOK, P. 441-449. &&

  • Deposit

    DEVOTO, R.H., AND MASLYN, R.M., 1977, SEDIMENTOLOGY AND DIAGENESIS OF THE LEADVILLE FORMATION AND CONTROLS OF LEAD-ZINC-SILVER DEPOSITS, CENTRAL COLORADO: MOUNTAIN GEOLOGIST, V. 14, NO. 1, P. 27-28. & &

  • Deposit

    HENDERSON, C.W., 1926, MINING IN COLORADO, A HISTORY OF DISCOVERY, DEVELOPMENT, AND PRODUCTION: USGS PROF. PAPER 138, P. 197-201. &&

  • Deposit

    KNOPF, ADOLPH, 1926, RECENT DEVELOPMENTS IN THE ASPEN DISTRICT, COLORADO: USGS BULL. 785, P. 1-28. & &

  • Deposit

    SPURR, J.E., 1898, GEOLOGY OF THE ASPEN MINING DISTRICT, COLORADO: USGS MON. 260 P.

  • Production

    VANDERWILT, J.W., 1947, MINERAL RESOURCES OF COLORADO: FIGS. FOR 1932-45; USBM MINERALS YEARBOOKS FOR REMAINING YEARS

General comments

Subject category Comment text
Deposit ADDITIONAL LITERATURE REFERENCES PERTINENT TO ASPEN DISTRICT INCLUDE--HEYL, A.V., 1964, OXIDIZED ZINC DEPOSITS OF THE UNITED STATES, PART 3--COLORADO: USGS BULL. 1135-C; MCCARTHY, J.H., JR., AND GOTT, G.B., 1966, THE DISTRIBUTION OF AG, PB, ZN, SB, AS, AND HG IN SOILS AT LENADO, ASPEN QUADRANGLE, COLORADO, WITH A PRELIMINARY GEOLOGIC MAP OF THE LENADO MINING DISTRICT, PITKIN COUNTY, COLORADO, BY BRUCE BRYANT: USGS OPEN-FILE REPT.; ROHLFING, D.P., 1938, THE COLORADO MINERAL BELT AND THE ASPEN MINING DISTRICT, PITKIN COUNTY, COLORADO: COLORADO MINING ASSOC. 1937 MINING YEAR BOOK, P. 16-17, 62-64, 90.; SPURR, J.E., 1909, ORE DEPOSITION AT ASPEN,COLORADO: ECON. GEOLOGY, V. 4, P. 310-320.; VANDERWILT, J.W., 1935, REVISION OF THE STRUCTURE AND STRATIGRAPHY OF THE ASPEN DISTRICT, COLORADO, AND ITS BEARING ON THE ORE DEPOSITS: ECON. GEOLOGY, V. 30, NO. 3, P. 223-241.; VOLIN, M.E., AND HILD, J.H., 1850, INVESTIGATION OF SMUGGLER LEAD-ZINC MINE, ASPEN, PITKIN COUNTY, COLORADO: USBM RI 4696.;
Deposit HENRICH, CARL, 1889, NOTES ON THE GEOLOGY AND ON SOME OF THE MINES OF ASPEN MOUNTAIN, PITKIN COUNTY, COLORADO: AIME TRANS., V. 17, P. 156-206. DETAILED RECORDS COMPLETED FOR FOLLOWING PRINCIPAL MINES: ARGENTUM-JUNIATA, ASPEN, ASPEN CONTACT, ASPEN MINING AND DRAINAGE TUNNEL, AE ASPEN MINING AND SMELTING CO., BEST FRIEND, BONNYBEL, BUSHWHACKER, CAMP BIRD, CELESTE, DELLA S., DUBUQUE TUNNEL, DURANT, HIGHLAND TUNNEL, HOPE, IOWA CHIEF, JUSTIC, LAST DOLLAR, LATE ACQUISTION, LEADVILLE, LITTLE ANNIE, LITTLE PERCY, MARY B., MIDNIGHT, MOLLIE GIBSON, NEWMAN TUNNEL, PARK REGENT, PARK TUNNEL, PRIDE OF ASPEN, PRINCESS LOUISE, SCHILLER, SMUGGLER, TILLY. ; INFO.SRC : 1 PUB LIT; 2 UNPUB REPT
Deposit PRINCIPAL PRODUCTIVE ORES OCCUR ALONG CONTACT AND SILVER FAULTS, WHICH WERE INTERPRETED AS BEDDING PLANE FAULTS SEPARATING THE WEST- TO NW-DIPPING LOWER DOLOMITE (REDCLIFF) AND UPPER BLUE LIMESTONE (CASTLE CREEK) MEMBERS OF THE LEADVILLE LIMESTONE AND SEPARATING THE CASTLE CREEK MEMBER FROM OVERLYING BELDEN FM., RESPECTIVELY. MORE RECENT INTERPRETATION ASSERTS THAT BRECCIA ZONES ORIGINALLY SEEN AT THESE HORIZONS ARE ACTUALLY SOIL RUBBLE OR PALEOKARST (SOLUTION COLLAPSE AND FILLING) ZONES, ALTHO BRYANT DID NOTE SOME EVIDENCE OF MOVEMENT ON THESE PLANES AT ASPEN. STRATIGRAPHIC AND STRUCTURAL CONTROL BY KARSTIFICATION AND FAULT MOVEMENT PROVIDED FAVORABLE SITES FOR MINERALIZING SOLUTIONS RICH IN AG-PB AND SECONDARILY IN ZN AND CU, ESPECIALLY WHERE SILVER AND CONTACT FAULTS ARE CUT BY CROSS FAULTING, SUCH AS DELLA AND LENADO SYSTEMS. IN ASPEN MTN-TOURTELLOTTE PARK AREA, ORES ALSO FOUND ASSOCIATED WITH APLITE PORPHYRY SILL IN BELDEN FM ALONG TROUGH OF ASPEN MTN SYNCLINE, COMPLICATED BY
Deposit NORTH-SUTH-TRENDING ASPEN MTN AND TOURTELLOTTE PARK FAULT SYSTEMS AND BY EAST-WEST-TRENDING BUTTE FAULT SYSTEM. FARTHER SOUTH IN ANNIE BASIN-RICHMOND HILL AREA, MINERALIZED FAULT BRECCIA ASSOCIATED WITH QUARTZ PORPHYRY SILL IN BELDEN IN STEEP FAULT CONTACT AGAINST PRECAMBRIAN QUARTZ MONZONITE AND CAMBRIAN-MISSISSIPPIAN SECTION ALONG EAST MARGIN OF CASTLE CREEK FAULT ZONE. MINOR AMOUNTS OF ORE FOUND IN PRECAMBRIAN AND OLDER PALEOZOIC SEDIMENTARY ROCKS AND IN PENNSYLVANIAN MAROON FM IN AREA. ORE OCCURS AS PODS, IRREGULAR MASSES, BRECCIA CEMENT, AND VUG FILLINGS. MINERALIZATION BELIEVED TO BE LIMITED TO ONE BRIEF PERIOD COMPARED TO DURATION OF FAULTING. FOUR-STAGE PARAGENESIS INTERPRETED AS 1) EARLY PRIMARY BARITE, 2) TETRAHEDRITE, TENNANTITE, POLYBASITE (PEARCEITE), SOME CONTEMPORANEOUS BARITE, 3) FINELY CRYSTALLINE GALENA, SUBORDINATE SPHALERITE (THE MILLING ORES), 4) OXIDATION TO NATIVE AG. BASTIN (1924) CLASSIFIES EARLY PRIMARY BARITE, TENNANTITE, RARE PYRITE, AND LATER PRIMARY
Deposit GALENA-SPHALERITE-CHALCOPYRITE, BORNTE, PEARCEITE, AND ARGENTITE ALL AS HYPOGENE; NATIVE AG, SOME PEARCEITE AND ARGENTITE(?), AND RARE CHALCOCITE AND COVELLITE AS SUPERGENE.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-MAR-1983 Schwochow, Stephen D. Colorado Geological Survey

Beyond USGS

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

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