Larson Volcano

Occurrence in Hinsdale county in Colorado, United States with commodities Silver, Gold, Copper, Lead, Zinc, Molybdenum

Sections on this page

Identification information
Geographic coordinates
Site location context
Geographic areas
Public Land Survey System information
Commodities
Materials information
Host and associated rocks
Nearby scientific data
Geologic structures
Controls for ore emplacement
Economic information about the deposit and operations
Mining district
Land status
Links to other databases
Bibliographic references
General comments
Reporter information

Geologic information

Identification information

Deposit ID	10094702
MRDS ID	D011578
Record type	Site
Current site name	Larson Volcano
Alternate or previous names	Larson Center

Geographic coordinates

Geographic coordinates:	-107.31035, 38.07861 (WGS84)
Elevation	3114
Relative position	2.5 TO 5.5 MILES N 10 W TO 3 TO 7 MILES N 35 E FROM LAKE CITY

Site location context

Political divisions (FIPS codes)

Hinsdale(county)

Colorado(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Lake City(quadrangle 1:24,000 scale)

Montrose(quadrangle 1:100,000 scale)

Montrose(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Upper Gunnison(hydrologic unit)

Gunnison(hydrologic accounting unit)

Gunnison(hydrologic subregion)

Upper Colorado(hydrologic region)

Federal lands

Grand Mesa, Uncompahgre and Gunnison National Forests(National Forest)

National Forest FS(Type of land area)

FS(Federal land areas administered by FS)

Uncompahgre Wilderness(Wilderness)

Wilderness FS(Type of land area)

FS(Federal land areas administered by FS)

Geographic areas

Country	State	County
United States	Colorado	Hinsdale

Public Land Survey System information

Meridian	Township	Range	Section	Fraction	State
New Mexico	044N;045N	004W;004W	01,02,03,10,11,12,13,14,15;25,27,28,33,34,35,36		Colorado

Comments on the location information

PRINCIPAL INTRUSIVE LIES ON WEST SIDE OF LAKE FORK GUNNISON RIVER 3 MILES NORTH OF LAKE CITY. TWO SMALLER PLUGS LIE ON EAST SIDE OF RIVER. INCLUDES LOWER PORTIONS OF LARSON CREEK, SPARLING GULCH, EATON GULCH, INDEPENDENCE GULCH, STONY CUT, BILL HARE GULCH, NOURSE CREEK, HOBO GULCH, AND HIGH BRIDGE GULCH. SECTIONS LISTED INCLUDE THOSE PERIPHERAL TO STOCK THAT ARE TRAVERSED BY RADIAL DIKES (WITHIN LIMIT OF LIPMAN'S (1976) MAPPING). AREA ACCESSIBLE VIA COLORADO RTE 149 SOUTH FROM U.S. RTE 50, BLUE MESA RESERVOIR, AND GATEVIEW, AND NORTH FROM LAKE CITY. ELEV AND LAT-LONG GIVEN ARE FOR APPROX CENTER OF PRINCIPAL INTRUSIVE, HILLTOP NEAR C SEC. 10, T44N, R4W. ; INFO FROM LAND.ST :1977

Commodities

Commodity	Importance
Silver	Primary
Gold	Primary
Copper	Primary
Lead	Primary
Zinc Critical	Secondary
Molybdenum	Tertiary

Comments on the commodity information

METALS AND ORE MINERALS LISTED ABOVE (EXCEPT MO) ARE UNVERIFIED BUT BASED ON MINERALIZATION AT OTHER PERIPHERAL PRECALDERA VOLCANIC CENTERS AROUND SAN JUAN-UNCOMPAHGRE CALDERA COMPLEX.

Materials information

Materials	Type of material
Chalcopyrite	Ore
Molybdenite	Ore
Pyrite	Ore
Sphalerite	Ore

Host and associated rocks

Host or associated

Associated

Rock type

Plutonic Rock > Granitoid > Monzonite

Stratigraphic age (youngest)	Oligocene
Stratigraphic age (youngest)	Oligocene

Host or associated Associated

Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite
Host or associated Associated

Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyodacite
Host or associated Associated

Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Quartz Latite

Host or associated	Associated
Rock type	Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite
Rock unit name	Early Intermediate-Composition Lavas And Related Rocks--Intrusive Rocks (Monzonite And Monzonite Porphyry);Early Intermediate-Composition Lavas And Related Rocks--Intrusive Rocks (Rhyolite Porphyry);Early Intermediate-Composition Lavas And Related Rocks--Intrusive Rocks (Andesite And Rhyodacite Porphyries);Early Intermediate-Composition Lavas And Related Rocks--Cone Breccias And Lava Flows
Rock description	Early Intermediate-Composition Lavas And Related Rocks--Intrusive Rocks (Monzonite And Monzonite Porphyry);Early Intermediate-Composition Lavas And Related Rocks--Intrusive Rocks (Rhyolite Porphyry);Early Intermediate-Composition Lavas And Related Rocks-

Host or associated Host

Rock type Plutonic Rock > Granitoid > Monzonite
Host or associated Host

Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite
Host or associated Host

Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyodacite
Host or associated Host

Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite

Host or associated	Host
Rock type	Plutonic Rock > Granitoid > Monzonite

Host or associated	Host
Rock type	Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite

Host or associated	Host
Rock type	Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyodacite

Host or associated	Host
Rock type	Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite

Nearby scientific data

(1)	-107.31035, 38.07861	ListMap

Economic information

Geologic structures

Type of structure	Regional
Structure description	San Juan Volcanic Field, San Juan Depression
Type of structure	Local
Structure description	San Juan-Uncompahgre Calderas, Lake City Caldera, Larson Volcano

Controls for ore emplacement

Plugs And Radiating Dikes From Precaldera Volcano

Comments on the geologic information

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, CONTINUOUS 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
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.
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,
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 (SILVERTONCALDERA), 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

Economic information about the deposit and operations

Development status	Occurrence
Commodity type	Metallic
Deposit size	Small
Significant	No

Mining district

District name	Larson Creek Area

Land status

Ownership category	National Forest

Comments on the workings information

PROSPECT PITS AND SEVERAL SHORT EXPLORATORY ADITS.

Reference information

Links to other databases

Agency	Database name	Acronym	Record ID	Notes
USGS	Mineral Resources Data System	MRDS	D011578

Bibliographic references

Deposit

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

STEVEN, T.A., AND OTHERS, 1977, MINERAL RESOURCES OF STUDY AREAS CONTIGUOUS TO THE UNCOMPAHGRE PRIMITIVE AREA, SAN JUAN MOUNTAINS, SOUTHWESTERN COLO RADO: USGS BULL. 1391-E, P. 36, 83-85, PLS. 1, 3.
Deposit

WORCESTER, P.G., 1919, MOLYBDENUM INDUSTRY: CGS BULL. 14, P. 67.

General comments

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

Subject category

Comment text

Deposit

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

Reporter information

Type	Date	Name	Affiliation	Comment
Reporter	01-MAR-1984	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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