Cimarron District

Site Name

Primary: Cimarron District
Secondary: Patented Claims
Secondary: Roscoe Conkling, MS 1697
Secondary: Government Stamp Lode, MS 2353
Secondary: Pay Day Placer, MS 9779
Secondary: Phil Sheridan, MS 9780
Secondary: Golden Eagle, MS 9781
Secondary: Good Enough, MS 13896
Secondary: Good Enough Extension, MS 13896
Secondary: Silver Jack, MS 20073

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Commodity

Primary: Lead
Primary: Gold
Primary: Silver

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Location

State: Colorado
County: Hinsdale
District: Cimarron 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: Jim Ingram (Silver Jack Mine)
Home Office: Montrose, Co.
Years: 1968 -

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Production

Not available

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Deposit

Record Type: District
Operation Category: Past Producer
Operation Type: Unknown
Year Last Production: 1931
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, Cimarron Volcano

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Alterations

Alteration Type: L
Alteration Text: Propylitization, Argillization, Silicification, Pyritization

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Rocks

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

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

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Analytical Data

Analytical Data: STEVEN AND OTHERS' (1977) SAMPLES SHOWED ANOMALOUS AG, AS, CU, MO, PB, SB, TE, ZN

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Materials

Ore: Pyrite
Gangue: Limonite

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Comments

Comment (Geology): CAUSED SIMPLE DOMAL RESURGENCE OF LAKE CITY CALDERA, WITH NE-TRENDING APICAL GRABEN FAULTING OVER DISTENDED CREST (REFLECTING SIMILAR TREND OF EUREKA GRABEN) 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 AND PERIPHERAL OUTFLOW DEPOSITS.

Comment (Deposit): INDIVIDUAL RECORD PREPARED FOR DISTRICT'S ON LY KNOWN PRODUCTIVE MINE: SILVER JACK. SECOND PREPAREDED FOR REPORTEDLY PRODUCTIVE UNNAMED MINE IN PORPHYRY BASIN. ; INFO.SRC : 1 PUB LIT; 2 UNPUB REPT

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): WITHIN AND ON SAN JUAN-UNCOMPAHGRE CALDERA MARGIN; (8) BROAD EPISODIC RESURGENT DOMING ALONG NE-TRENDING AXIS OF SAN JUAN DEPRESSION; DISTENTION FRACTURING ALONG CREST PERMITTED DOWNFAULTING OF EUREKA GRABEN, 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, CONTINOUS VERTICAL TO STEEP INWARD-DIPPING RING FAULT; ASH FLOWS INTERTONGUING WITH COLLAPSE BRECCIAS; (10) FLOWS AND DOMES OF VISCOUS, SILICIC LAVAS (GRASSY MOUNTAIN AND RED MOUNTAIN QUARTZ LATITES)(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

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 SILVERTON CALDERA NESTED WITHIN SAN JUAN CALDERA, WITH GREATEST DISPLACEMENT ON SOUTH MARGIN AND GRABEN-FAULTED MONOCLINE ON NE; PRE- AND POST-COLLAPSE MONZONITIC INTRUSIONS

Comment (Commodity): ORE MINERALS LISTED ABOVE ARE UNVERIFIED BUT ARE PROBABLY SIMILAR TO SULFIDE MINERALIZATION AT OTHER PRECALDERA VOLCANIC CENTER (CARSON) TO SOUTH. CU AND ZN ALSO MAY BE PRESENT, BUT THESE ARE UNVERIFIED.

Comment (Development): EARLY HISTORY OF DISTRICT LARGELY UNKNOWN, BUT DISCOVERIES PROBABLY MADE ABOUT 1880. FIRST PATENTED CLAIM (ROSCOE CONKLING) SURVEYED IN 1883 BY HENRY O. MINER, FOLLOWED IN 1885 BY GOVERNMENT STAMP LODE. IN 1895-96, JOHN H. MCILROY SURVEYED AND PATENTED PAY DAY PLACER AND THE PHIL SHERIDAN AND GOLDEN EAGLE CLAIMS. LAST CLAIM (SILVER JACK) SURVEYED AND PATENTED IN 1921-22 BY C.M. HYDE AND JOHN L. VAUGHN. SILVER JACK WAS DISTRICT'S OLNLY KNOWN PRODUCTIVE MINE, REPORTEDLY LAST WORKED IN 1931

Comment (Deposit): GENERAL GEOLOGY OF DISTRICT CHARACTERIZED BY THICK SEQUENCE OF PORPHYRITIC ANDESITE, RHYODACITE, AND QUARTZ LATITE FLOWS AND FLOW BRECCIAS INTERBEDDED WITH ANDESITE AND PHYODACITE EXPLOSION BRECCIAS, MUDFLOW BRECCIAS, LOCAL INDURATED SPATTER AGGLUTINATES, AND A FEW BRECCIATED LAVA FLOWS. SEQUENCE IS INTRUDED BY (1) PLUGS OF MONZONITE/MONZONITE PORPHYRY AND RHYOLITE PORPHYRY, AND (2) PLUGS AND RADIATING DIKES OF ANDESITE AND RHYODACITE PORPHYRY. EARLY INTERMEDIATE-COMPOSITION FLOWS/BRECCIAS AND INTRUSIVE ROCKS OF CIMARRON VOLCANIC CENTER ARE CONSIDERED TO PREDATE FORMATION OF SAN JUAN DEPRESSION AND ASSOCIATED CALDERAS, AND THEREFORE REPRESENT OLDEST STAGE OF MINERALIZATION IN CALDERA COMPLEX AREA. MINERALIZED CORE CONTAINS DISSEMINATED SULFIDES AND LOCAL VEINS (LIPMAN AND OTHERS, 1976, P. 577).

Comment (Workings): SHAFTS, TUNNELS, AND DRIFTS (SILVER JACK MINE); PROBABLE SURFACE PROSPECTS

Comment (Location): DISTRICT LIES ALONG EAST FORK OF CIMARRON RIVER ON NORTH SIDE OF LAKE CITY-SILVERTON CALDERA COMPLEX, EXTENDING FROM SILVER CREEK DOWNSTREAM (NORTH) ABOUT TWO MILES. PROMINENT LANDMARKS INCLUDE SHEEP MOUNTAIN, SILVER MOUNTAIN, PORPHYRY BASIN, AND UNCOMPAHGRE PEAK. DISTRICT ACCESSIBLE VIA TRAIL UP EAST FORK CIMARRON RIVER SSE FROM U.S. RTE 50; VIA TRAILS NORTH FROM HENSON CREEK; VIA TRAIL UP-BIG BLUE CREEK SW FROM LAKE FORK GUNNISON RIVER. DISTRICT EXTENDS NORTHWARD ONTO SHEEP MOUNTAIN (1963) QUAD. ELEV AND LAT-LONG GIVEN ARE FOR APPROX CENTER OF DISTRICT AT CONFLUENCE OF EAST FORK CIMARRON RIVER AND UNNAMED TRIBUTARY GULCH DRAINING NW SLOPE OF SILVER MTN, IN N2 NW SEC. 36, T45N, R6W (UNSURVEYED SECTION). ; INFO FROM LAND.ST :1975

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References

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

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, COLORADO: USGS JOUR. RESEARCH, V. 1, NO. 6, P. 627-642.

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.

Reference (Deposit): BLM MINERAL SURVEYS MS 1697, 2353, 9779, 9780, 9781, 13896, 20073

Reference (Deposit): LIPMAN, P.W., AND OTHERS, 1976, MULTIPLE AGES 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, H.H., 1983, COMPILATION OF REVISED AGES OF VOLCANIC UNITS IN THE SAN JUAN MOUNTAINS, COLORADO--RECALCULATED K-AR AGE DETERMINATIONS USING IUGS CONSTANTS: USGS OPEN-FILE REPT. OFR-83-668.

Reference (Deposit): STEVEN, T.A., AND OTHERS, 1977, MINERAL RESOYRCES OF STIDY AREAS CONTIGUOUS TO THE UNCOMPAHGRE PRIMITIVE AREA, SAN JUAN MOUNTAINS, SOUTHWESTERN COLORADO: USGS BULL. 1391-E, P. 36-37, 85-86, PLS. 1, 3.

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