Geroe Creek

Prospect in Alaska, United States with commodities Copper, Molybdenum

Sections on this page

Identification information
Geographic coordinates
Site location context
Geographic areas
Commodities
Materials information
Alteration
Mineral occurrence model information
Host and associated rocks
Nearby scientific data
Economic information about the deposit and operations
Mining district
Links to other databases
Bibliographic references
General comments
Reporter information

Geologic information

Identification information

Deposit ID	10001397
MRDS ID	A012140
Record type	Site
Current site name	Geroe Creek
Alternate or previous names	MAS claims

Geographic coordinates

Geographic coordinates:	-148.81333, 67.67973 (WGS84)
Relative position	The reference point is at an elevation of 5,500 feet, near the divide between Geroe Creek and Willow Creek (NW1/4 sec. 24, T. 33 N., R. 6 W., of the Fairbanks Meridian) and at the center of a large claim block (239 claims). A second large claim block northeast of of the Geroe property, and contiguous with its northeast corner (U.S. Bureau of Mines, 1973), may be part of this large property. The location is accurate within a 1-mile radius.

Geographic coordinates:

-148.81333, 67.67973 (WGS84)

Relative position

The reference point is at an elevation of 5,500 feet, near the divide between Geroe Creek and Willow Creek (NW1/4 sec. 24, T. 33 N., R. 6 W., of the Fairbanks Meridian) and at the center of a large claim block (239 claims). A second large claim block northeast of of the Geroe property, and contiguous with its northeast corner (U.S. Bureau of Mines, 1973), may be part of this large property. The location is accurate within a 1-mile radius.

Site location context

Political divisions (FIPS codes)

Yukon-Koyukuk(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Chandalar C-4(quadrangle 1:63,360 scale)

Chandalar N(quadrangle 1:100,000 scale)

Chandalar C(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Alaska(hydrologic region)

Geographic areas

Country	State
United States	Alaska

Commodities

Commodity	Importance
Copper	Primary
Molybdenum	Primary

Comments on the commodity information

Ore Material = Copper sulfides (chalcopyrite)

Materials information

Materials	Type of material
Chalcopyrite	Ore
Molybdenite	Ore
Chlorite	Gangue
Quartz	Gangue
Sericite	Gangue

Alteration

(Local) Seritization and propylitization of porphyritic host rocks; quartz-sericite-chlorite plus or minus epidote; calcite.

Mineral occurrence model information

Model code	79
USGS model code	21a
Deposit model name	Porphyry Cu-Mo
Mark3 model number	2

Host and associated rocks

Host or associated Associated

Rock type Plutonic Rock > Mafic Intrusive Rock > Diorite

Stratigraphic age (youngest) Late Cretaceous
Host or associated Associated

Rock type Plutonic Rock > Granitoid > Granite

Rock unit name Geroe Creek Pluton

Rock description Geroe Creek Pluton
Host or associated Host

Rock type Plutonic Rock > Granitoid > Granite

Host or associated	Associated
Rock type	Plutonic Rock > Granitoid > Granite
Rock unit name	Geroe Creek Pluton
Rock description	Geroe Creek Pluton

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

Nearby scientific data

(1)	-148.81333, 67.67973	ListMap

Economic information

Comments on the geologic information

Geologic Description = The Geroe Creek prospect is one of several quartz stockworks and altered zones in the northeast-trending belt of Devonian peraluminous biotite-muscovite granites of the Baby Creek batholith and the Devonian metaluminous biotite-hornblende granites and granodiorites of the Horace Mountain plutons (Newberry and others, 1986). Porphyritic phases are locally present in these plutons, and Young and others (1997) reported that the mineralizing intrusives are porphyritic meta-granodiorites and biotite meta-granites. The country rocks are mainly Paleozoic schists and marble along with peraluminous meta-granodiorite. Young and others (1997) also noted that there is no skarn development in the calcareous rocks. The veinlets in the stockworks on the Geroe prospect contain disseminated molybdenite, chalcopyrite, and pyrite along with intense quartz-sericite-chlorite plus or minus epidote alteration. Eakins and others (1983, p. 41) reported Mo grades as much as 0.1 percent, and Nokleberg and others (1987) report that zones in the plutons as much as several meters thick contain values of 0.6 percent Cu, 0.02 percent Mo, and 0.1 grams of gold per ton.
Age = Devonian based on reported Early Devonian Pb/Pb zircon ages from the associated Baby Creek batholith and Horace Mountain plutons (Dillon and others, 1996).

Economic information about the deposit and operations

Development status	Prospect
Commodity type	Metallic

Comments on exploration

Status = Inactive

Mining district

District name	Chandalar and Koyukuk

Comments on the workings information

Workings / Exploration = 239 claims staked in 1975 and 1976.

Reference information

Links to other databases

Agency	Database name	Acronym	Record ID	Notes
USGS	Mineral Resources Data System	MRDS	A012140
USGS	Alaska Resource Data File	ARDF	CH053

Bibliographic references

Deposit

U.S. Bureau of Mines, 1973, Alaska 1:250,000-scale quadrangle map overlays showing mineral deposit locations, principal minerals, and number and type of claims: U.S. Bureau of Mines Open-File Report 20-73, 95 overlays (updated in 1986, 1987).
Deposit

Grybeck, D.J., 1977, Known mineral deposits of the Brooks Range, Alaska: US Geological Survey Open-File Report 77-166C, 41 p., 1 sheet, scale 1:1,000,000.
Deposit

DeYoung, J.H., Jr., 1978, Mineral resources map of the Chandalar quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-878-B, 2 sheets, scale 1:250,000.
Deposit

Arctic Environmental Information and Data Center, 1982, Mineral terranes of Alaska: University of Alaska, Fairbanks, 7 sheets, scale 1:1,000,000.
Deposit

Bundtzen, T.K., Eakins, G.R., and Conwell, C.N., 1982, Review of Alaska mineral resources 1981: Alaska Division of Geological and Geophysical Surveys Annual Report 1981, 48 p., 2 sheets, scale 1:3,000,000.
Deposit

Bundtzen, T.K., Eakins, G.R., and Conwell, C.N., 1982, Alaska mineral resources 1981-82: Alaska Division of Geological and Geophysical Surveys Annual Report 1981-82, 153 p., 4 sheets, scale 1:2,500,000.
Deposit

Eakins, G.R., Bundtzen, T.K., Robinson, M.S., Clough, J.G., Green, C.B., Clautice, K.H., and Albanese M.A., 1983, Alaska's mineral industry, 1982, Alaska Division of Geological and Geophysical Surveys Special Report 31, 63 p.
Deposit

Newberry, R.J., Dillon, J.T., and Adams, D.D., 1986, Regionally metamorphosed calc-silicate-hosted deposits of the Brooks Range, northern Alaska: Economic Geology, v. 81, p. 1728-1752
Deposit

Nokleberg, W.J., Bundtzen, T.K., Berg, H.C., Brew, D.A., Grybeck, D.J., Robinson, M.S., Smith, T.E., and Yeend, W., 1987, Significant metalliferous lode deposits and placer districts of Alaska: U.S. Geological Survey Bulletin 1786, 104 p.
Deposit

Maas, K.M., 1987, Maps summarizing land availability for mineral exploration and development in northern Alaska, 1986: U.S. Bureau of Mines Open-File Report 10-87, 33 sheets.
Deposit

Nokleberg, W.J., Bundtzen, T.K., Berg, H.C., Brew, D.A., Grybeck, Donald, Robinson, M.S., Smith, T.E., and Yeend, Warren, 1988, Metallogeny and major mineral deposits of Alaska: U.S. Geological Survey Open-File Report 88-73, 97 p., 2 plates, scale 1:5,000,000.
Deposit

Nokleberg, W.J., Bundtzen, T.K., Grybeck, D.J., Koch, R.D., Eremin, R.A., Rozenblum, I. S., Sidorov, A.A., Byalobzhesky, S.G., Sosunov, G.M., Shpikerman, V.I., Gorodinsky, M.E., 1993, Metallogenesis of mainland Alaska and the Russian Northeast: U.S. Geological Survey Open-File Report 93-0339, 3 sheets, 230 p.
Deposit

Young, L.E., St. George, P., and Bouley, B., 1997, Porphyry copper deposits in relation to the magmatic history and palinspastic restoration of Alaska, in Goldfarb, R.J., and Miller, L.D., (eds.), Mineral deposits of Alaska: Economic Geology Monograph 9, p. 306-333.

Comments on the references

Primary Reference = Newberry and others, 1986

General comments

Subject category	Comment text
Deposit	Model Name = Porphyry Cu-Mo (Cox and Singer, 1986; model 21a)
Deposit	Other Comments = See also: Venus (CH065), Victor (CH064), Eva (CH063) and Evelyn Lee (CH059) prospects; Alaska Kardex No. 031-68 (Kardex is a card file mining claim information system located at the State of Alaska DNR Public Information Center in Fairbanks).

Reporter information

Type	Date	Name	Affiliation	Comment
Reporter	17-NOV-1999	J.M. Britton	U.S. Geological Survey

Beyond USGS

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

Maps centered on this site

Authoritative Alaska resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.

Geroe Creek

Geologic information

Identification information

Geographic coordinates

Site location context

Geographic areas

Commodities

Comments on the commodity information

Materials information

Alteration

Mineral occurrence model information

Host and associated rocks

Nearby scientific data

Economic information

Comments on the geologic information

Economic information about the deposit and operations

Comments on exploration

Mining district

Comments on the workings information

Reference information

Links to other databases

Bibliographic references

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Deposit

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Deposit

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Comments on the references

General comments

Reporter information

Beyond USGS

Maps centered on this site

Authoritative Alaska resources