Sherman District

Site Name

Primary: Sherman District
Secondary: Patented Claims: George Washington, MS 312
Secondary: Colorado Placer, MS 375
Secondary: Rebel Boy, MS 599
Secondary: Eastern Rebel Boy, MS 600
Secondary: I. X. L., MS 1289
Secondary: Minnie Lee, MS 1473a
Secondary: Minnie Lee Mill Site, MS 1473b
Secondary: Black Wonder, MS 1939
Secondary: Mountain View, MS 2621
Secondary: No. 2 Ruby, MS 2637
Secondary: Black Wonder Extension, MS 4663
Secondary: Sterling, MS 6267
Secondary: Nellie G., MS 6267
Secondary: Conalan, MS 6267
Secondary: Dolphim, MS 6267
Secondary: Come Up, MS 8402
Secondary: Mineral Flower, MS 8402
Secondary: Black Wonder No. 2, MS 8493
Secondary: Crescent, MS 12429
Secondary: Meteor, MS 12429
Secondary: Tillman, MS 12429
Secondary: Wanimoo, MS 12429
Secondary: Morning Star, MS 12879
Secondary: Gracie, MS 15503
Secondary: Niagara, MS 15503

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Commodity

Primary: Silver
Primary: Gold
Secondary: Lead
Secondary: Copper
Tertiary: Zinc
Tertiary: Bismuth
Tertiary: Molybdenum

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Location

State: Colorado
County: Hinsdale
District: Sherman District

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Land Status

Land ownership: Private
Note: the land ownership field only identifies whether the area the mine is in is generally on public lands like Forest Service or BLM land, or if it is in an area that is generally private property. It does not definitively identify property status, nor does it indicate claim status or whether an area is open to prospecting. Always respect private property.

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Holdings

Not available

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Workings

Not available

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Ownership

Owner Name: Coburn (Estate) (George Washington Group)
Home Office: Boston, Ma.
Years: 1932 -

Owner Name: Roy Van Houten And Others (George Washington Group)
Home Office: Lake City, Co.
Years: 1932 -

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Production

Not available

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Deposit

Record Type: District
Operation Category: Past Producer
Deposit Type: Vein
Operation Type: Unknown
Year First Production: 1882
Year Last Production: 1925
Discovery Year: 1877
Discovery Method: Ore-Mineral In Place
Years of Production:
Organization:
Significant: N
Deposit Size: S

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Physiography

General Physiographic Area: Rocky Mountain System
Physiographic Province: Southern Rocky Mountains

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Mineral Deposit Model

Not available

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Orebody

Not available

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Structure

Type: R
Description: San Juan Volcanic Field, San Juan Depression

Type: L
Description: San Juan-Uncompahgre Calderas, Lake City Caldera, Silverton Caldera, Eureka Graben

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Alterations

Not available

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Rocks

Name: Quartz Monzonite
Role: Associated
Age Type: Host Rock Unit
Age Young: Oligocene

Name: Quartz Monzonite
Role: Associated
Age Type: Associated Rock
Age Young: Oligocene

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Analytical Data

Not available

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Materials

Ore: Galena
Ore: Sphalerite
Ore: Molybdenite
Ore: Tetrahedrite
Ore: Chalcopyrite
Ore: Pyrite
Gangue: Calcite
Gangue: Barite
Gangue: Quartz

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Comments

Comment (Geology): WITHIN AND ON SAN JUAN-UNCOMPAHGRE CALDERA MARGIN; (8) BROAD EPISODIC RESURGENT DOMING ALONG CREST PERMITTED DOWNFAULTING OF EUREKA BRABEN, EXTENDING FROM WITHIN SILVERTON CALDERA NE ACROSS MEDIAL SEPTUM (COMPOSED OF PRECAMBRIAN GRANITE) SEPARATING SAN JUAN AND UNCOMPAHGRE CALDERAS; (9) ERUPTION OF MIOCENE SUNSHINE PEAK SILICIC ALKALI RHYOLITE TUFF (23.0 M.Y.) WITH CONCURRENT COLLAPSE OF LAKE CITY CALDERA (NESTED WITHIN UNCOMPAHGRE CALDERA) ALONG SINGLE, CONTINUOUS VERTICAL TO STEEP INWARD-DIPPING RING FAULT; ASH FLOWS INTERONGUING WITH COLLAPSE BRECCIAS; (10) FLOWS AND DOMES OF VISCOUS, SILICIC LAVAS (GRASSY MOUNTAIN AND RED MOUNTAIN QUARTZ LATITEA) (23.3 TO 22.8 M.Y.) ISSUED FROM RING-FAULT VENTS ON EAST SIDE OF LAKE CITY CALDERA; YOUNGER EMPLACEMENT OF ENE-TRENDING CHAIN OF RHYOLITIC INTRUSIVES (18.5 M.Y.) IN UNCOMPAHGRE CALDERA MOAT AREA NORTH OF LAKE CITY CALDERA; (11) UPWARD MOVEMENT OF SHALLOW GRANITIC MAGMA CAUSED SIMPLE DOMAL RESURGENCE OF LAKE CITY CALDERA, WITH NE-TRENDING

Comment (Geology): APICAL GRABEN FAULTING OVER DISTENDED CREST (REFLECTINT SIMILAR TREND OF EUREKA) AND CHAOTIC COLLAPSE BRECCIAS ON SW SIDE; (12) MIOCENE TO PLIOCENE REGIONAL EXTRUSION OF BIMODAL MAFIC-SILICIC (BASALTIC TO RHYOLITIC) FLOWS OF HINSDALE FM (18.8 TO 12.6 M.Y.) PERIPHERAL TO CALDERA COMPLEX AND RELATED TO INITIAL DEVELOPMENT OF RIO GRANDE RIFT AND REGIONAL EASTWARD TILTING OF EAST PART OF SAN JUAN VOLCANIC FIELD; (13) LATE TERTIARY AND QUATERNARY EROSION, DISSECTION, EXTENSIVE MASS WASTING, AND GLACIATION OF CALDERAS ADN PERIPHERAL OUTFLOW DEPOSITS.

Comment (Deposit): Discovery Year: LATE 1870S

Comment (Geology): GENERALIZED EVOLUTION OF UNCOMPAHGRE-SAN JUAN, SILVERTON, AND LAKE CITY CALDERAS (LIPMAN AND OTHERS, 1973; STEVEN AND LIPMAN, 1976; HON AND MEHNERT, 1983): (1) ERUPTION OF EARLY OLIGOCENE (35.6 TO 31.9 M.Y.) INTERMEDIATE-COMPOSITION LAVAS, BRECCIAS, AND PYROCLASTICS (SAN JUAN AND LAKE FORK FMS), AND LATERALLY ASSOCIATED VOLCANICLASTICS FROM CLUSTERED CENTRAL-VENT SHIELD VOLCANOES (LARSON, CARSON, AND CIMARRON CENTERS) COMPRISED OF RHYOLITE PORPHYRY, ANDESITIC TO RHYODACITIC, AND MONZONITIC INTRUSIVES; (2) LOWER FLANKS AND COALESCING OUTFLOW APRONS OF SHIELD VOLCANOES COVERED BY ASH-FLOW SHEETS (UTE RIDGE (29.1 M.Y.) AND BLUE MESA TUFFS) FROM NEARBY UTE CREEK AND LOST LAKE CENTERS TO SE; (3) ERUPTION OF RELATIVELY SMALL VOLUME OF DILLON MESA TUFF (29 TO 28 M.Y.) PROBABLY FROM AREA OF INCIPIENT UNCOMPAHGRE CALDERA; (4) VOLUMINOUS ERUPTION OF WIDESPREAD SAPINERO MESA TUFF (CIRCA 28 M.Y.) FROM SAN JUAN DEPRESSION, CONCURRENT COLLAPSE OF SAN JUAN AND UNCOMPAHGRE CALDERAS WITHIN DEPRESSION,

Comment (Geology): AND DEPOSITION OF THICK INTRA-CALDERA TUFFS AND INTERBEDDED LANDSLIDE BRECCIAS OF ITS EUREKA MEMBER; (5) EARLY POSTSUBSIDENCE LOCAL DOMING AND ERUPTION OF VISCOUS, PORPHYRITIC RHYODACITE TO QUARTZ LATITE LAVAS GRADING UPWARD INTO ANDESITE IN SAN JUAN CALDERA, WITH PERIPHERAL DEPOSITION OF BEDDED TUFFS, VOLCANICLASTICS, AND LACUSTRINE SEDIMENTS (BURNS FM); LATER INFILLING PREDOMINANTLY VOLCANICLASTIC SEDIMENTS AND MUDFLOW BRECCIAS (HENSON FM), PARTLY OVERFLOWING SE CALDERA WALL; (6) INFILL SEQUENCE OVERLAIN BY ASH-FLOW TUFFS FROM ADJACENT ERUPTIVE CENTERS--FISH CANYON (LA GARITA CALDERA) (28.5 M.Y.), CRYSTAL LAKE (SILVERTON CALDERA), CARPENTER RIDGE (BACHELOR CALDERA), WASON PARK (SOURCE UNKNOWN), AND NELSON MOUNTAIN (SAN LUIS CALDERA); (7) ERUPTION OF CRYSTAL LAKE TUFF (27.5 M.Y.) RESULTED IN TRAPDOOR COLLAPSE OF SIVERTON CALDERA NESTED WITHIN SAN JUAN CALDER A, WITH GREATEST DISPLACEMENT ON SOUTH MARGIN AND GRABEN-FAULTED MONOCLINE ON NE; PRE- AND POST-COLLAPSE MONZONITIC INTRUSION

Comment (Deposit): BLM CLAIM RECORDS ASSIGN DISTRICT NAME OF "SHERMAN" TO CLAIMS AROUND OLD TOWNSITE OF SHERMAN. GEORGE WASHINGTON CLAIM (MS 312) ORIGINALLY ASSIGNED TO PARK DISTRICT LOCATED TO NW, BUT BASED ON CONTIGUITY WITH OTHER SHERMAN DISTRICT CLAIM, IT IS INCLUDED IN SHERMAN DISTRICT. INDIVIDUAL RECORDS PREPARED FOR DISTRICT'S PRINCIPAL PROPERTIES, MOST OF WHICH APPEAR TO HAVE PRODUCED SMALL AMOUNTS OF ORE: BLACK WONDER, GEORGE WASHINGTON GROUP, MINNIE LEE, AND STERLING GROUP. ; INFO.SRC : 1 PUB LIT; 2 UNPUB REPT; 4 OTHER SRC

Comment (Deposit): DISTRICT LOCALIZED MAINLY IN PRECAMBRIAN GRANITIC ROCKS THAT BORDER THE UNCOMPAHGRE-LAKE CITY CALDERAS ON SOUTH AND SAN JUAN CALDERA ON SE, AND PROJECTING NW TO FORM THE SEPTUM THAT SEPARATED THE SAN JUAN AND UNCOMPAHGRE CALDERAS FOLLOWING THEIR COLLAPSE INTO SAN JUAN DEPRESSION. GRANITE OF CATARACT CANYON IS MASSIVE, MEDIUM- TO COARSE-GRAINED GRANITE OR QUARTZ MONZONITE, WITH LOCAL WEAK, STEEPLY DIPPING FOLIATION OR LINEATION DEFINED BY ALIGNED MICROCLINES. CUTTING GRANITE ARE SEVERAL PROMINENT CAMBRO-ORDOVICIAN DIABASE DIKES TRENDING GENERALLY NW-SE AND WNW-ESE. DIKES CONSIST OF FINELY INTERGROWN PLAGIOCLASE AND AUGITE, AND HAVE BEEN RECRYSTALLIZED TO FINE-GRAINED ASSEMBLAGE OF SERICITE, CHLORITE, ALBITE, EPIDOTE, AND CALCITE, QUARTZ VEINS LOCALLY PERSISTENT ALONG DIKE MARGINS. ORE AND GANGUE NIMERALS LISTED ARE INFERRED ON BASIS OF SIMILARITY WITH OCCURRENCES IN PARK DISTRICT TO NW AND IN LAKE DISTRICT TO NE, AS DESCRIPTIONS FOR SHERMAN DISTRICT ARE LACKING. AU COULD OCCUR IN

Comment (Location): DISTRICT LOCATED ALONG LAKE FORK GUNNISON RIVER AT CONFLUENCE WITH COTTONWOOD CREEK AND ALONG UPPER COTTONWOOD CREEK AT CONFLUENCES OF SNARE CREEK AND CUBA GULCH; INCLUDES LOWER PART OF CATARACT GULCH. PROMINENT LANDMARKS INCLUDE SUNSHINE PEAK, WHITECROSS MOUNTAIN, CARSON PEAK, HANDIES PEAK, AND SEVERAL PEAKS AT HEAD OF SNARE CREEK ON HINSDALE-SAN JUAN COUNTY LINE TO WEST (JONES MOUNTAIN, NIAGARA PEAK, CROWN MOUNTAIN). DISTRICT EXTENDS WESTWARD ONTO HANDIES PEAK (1955) QUAD. DISTRICT ACCESSIBLE VIA ROAD UP LAKE FORK SW FROM LAKE CITY; VIA ROAD NORTH FROM SILERTON UP ANIMAS REIVER, UP CINNAMON CREEK, OVER CINNAMON PASS, AND DOWNVERTON UP ANIMAS RIVER, UP CINNAMON CREEK, OVER CINNAMON PASS, AND DOWN LAKE FORK, SECTIONS LISTED ABOVE INCLUDE ONLY THOSE CONTAINING PATENTED CLAIMS. ELEV AND LAT-LONG GIVEN ARE FOR OLD TOWNSITE OF SHERMAN AT CONFLUENCE OF LAKE FORK AND CONTTONWOOD CREEK IN APPROX N2 SEC. T42N, R5W (UNSURVEYED SECTION.) ; INFO FROM LAND.ST :1977

Comment (Deposit): TELLURIDES; AG PROBABLY OCCURS IN TETRAHEDRITE OR CHALCOPYRITE. BI MINERAL(S) UNKNOWN BUT COULD BE IN ANY OF SEVERAL COMPLEX SULFIDES OF CU, PB, AND BI: AIKINITE, MATILDITE, SCHIRMERITE, BISMUTHINITE, OR TELLUROBISMUTHITE (IN LAKE DISTRICT), OR LILLIANITE (IN PARK DISTRICT). DESCRIPTIONS OF MINERALIZATION ALSO LACKING FOR DISTRICT. VEINS AT BLACK WONDER AND GEORGE WASHINGTON MINES COULD BE ASSOCIATED WITH RING FRACTURES OF LAKE CITY CALDERA OR WITH LOCAL QUARTZ VEINS ALONG DIABASE DIKES CUTTING GRANITE AT OR JUST BEYOND SOUTH RIM OF UNCOMPAHGRE AND LAKE CITY CALDERAS. THESE WOULD MOST LIKELY BE ASSOCIATED WITH LAKE CITY CALDERA FORMATION AND, THEREFORE, MIOCENE IN AGE. MINERALIZATION IN SNARE CREEK-CUBA GULCH AREA (MINNIE LEE AND STERLING) LOCATED ON AND JUST BEYOND SE RIM OF SAN JUAN CALDERA: MINNIE LEE IN GRANITE AND STERLING ON CALDERA RIM OR IN SAN JUAN CALDERA INFILL SEQUENCE. AGE UNCERTAIN, POSSIBLY LATE OLIGOCENE ASSOCIATED WITH SAN JUAN COLLAPSE AND FORMATION OF EUREKA GRABEN.

Comment (Workings): DESCRIBED PROPERTIES DEVELOPED BY SHAFTS UP TO 40 FT DEEP, CROSSCUT AND DRIFT TUNNELS UP TO 300 FT LONG WITH EXTENSIVE DRIFTS; SURFACE CUTS; ONE OR TWO OLD MILLS.

Comment (Development): EARLY HISTORY OF DISTRICT LARGELY UNKNOWN. FIRST PATENTED CLAIM (GEORGE WASHINGTON) SURVEYED IN 1879 BY MARY GARBUTT AND OTHERS. MOST OF REMAINING CLAIMS SURVEYED AND PATENTED INTERMITTENTLY FROM 1880 TO 1894, WITH LAST SEVERAL BETWEEN 1898 AND 1904. SMALL AMOUNT OF PRODUCTION FROM DISTRICT PROBABLY REALIZED BETWEEN 1880 AND 1900. BLACK WONDER MINE LAST ACTIVE ABOUT 1908. PROBABLY SOME EXPLORATION AND DEVELOPMENT SPORADICALLY AT BLACK WONDER, GEORGE WASHINGTON, AND MINNIE LEE MINES BETWEEN 1923 AND 1932. LAST REPORTED ACTIVITY WAS EXPLORATION AND DEVELOPMENT AT STERLING GROUP IN 1964-1969, CONSISTING OF DIAMOND DRILLING, GEOPHYSICAL AND GEOCHEMICAL WORK.

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References

Reference (Deposit): LIPMAN, P.W., AND OTHERS, 1973, REVISED VOLCANIC HISTORY OF THE SAN JUAN, UNCOMPAHGRE, SILVERTON, AND LAKE CITY CALDERAS IN THE WESTERN SAN JUAN MOUNTAINS: USGS JOUR. RESEARCH, V. 1, NO. 6, P. 627-642.

Reference (Deposit): LIPMAN, P.W., AND OTHERS, 1976, MULTIPLE AGES OF MID-TERTIARY MINERALIZATION AND ALTERATION IN THE WESTERN SAN JUAN MOUNTAINS, COLORADO: ECON. GEOLOGY, V. 71, NO. 3, P. 571-588.

Reference (Deposit): HON,KEN, AND MEHNERT, N.H., 1983, COMPILATION OF REVISED AGES OF VOLCANIC UBITS IN THE SAN JUAN MOUNTAINS, COLORADO--RECALCULATED K/AR AGE DETERMINATIONS USING IUGS CONSTANTS: USGS OPEN-FILE REPT. OFR-83-688.

Reference (Deposit): LIPMAN, P.W., 1976, GEOLOGIC MAP OF THE LAKE CITY CALDERA AREA, WESTERN SAN JUAN MOUNTAINS, SOUTHWESTERN COLORADO: USGS MAP I-962.

Reference (Deposit): WORCESTER, P.G., 1919, MOLUBDENUM DEPOSITS OF COLORADO WITH GENERAL NOTES ON THE MOLYBDENUM INDUSTRY: CGS BULL. 14, P. 68.

Reference (Deposit): LIPMAN, P.W., 1976, CALDERA-COLLAPSE BRECCIAS IN THE WESTERN SAN JUAN MOUNTAINS, COLORADO: GEOL. SOC. AMERICA BULL., V. 87, NO. 10, P. 1397-1410.

Reference (Deposit): SLACK, J.F., 1980, MULTISTAGE VEIN ORES OF THE LAKE CITY DISTRICT, WESTERN SAN JUAN MOUNTAINS, COLORADO: ECON. GEOLOGY, V. 75, NO. 7, P. 963-991.

Reference (Deposit): A BLM MINERAL SURVEYS MS 312, 375, 599, 600, 1289, 1473A&B, 1939, 2621, 2637, 46638, 6267, 8402, 8493, 12429, 12879, 15503

Reference (Deposit): STEVEN, T.A., AND LIPMAN, P.W., 1976, CALDERAS OF THE SAN JUAN VOLCANIC FIELD, SOUTHWESTERN COLORADO: USGS PROF. PAPER 958, P. 10-16.

Reference (Deposit): COLORADO DIV. MINES INF. REPTS.

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