Unnamed (Cobblestone River)

Occurrence in Alaska, United States with commodity Graphite

Sections on this page

Identification information
Geographic coordinates
Site location context
Geographic areas
Commodities
Materials 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	10002103
MRDS ID	A012967
Record type	Site
Current site name	Unnamed (Cobblestone River)

Geographic coordinates

Geographic coordinates:	-165.46721, 64.98012 (WGS84)
Relative position	This occurrence is near an unnamed west-flowing tributary to the upper Cobblestone River. It is near the center of section 24, T. 6 S., R. 34 W., Kateel River Meridian. It is on a minor ridge at about 1,400 feet elevation. The occurrence is locality 38 of Hummel (1962 [MF 248]).

Site location context

Political divisions (FIPS codes)

Nome(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Nome D-1(quadrangle 1:63,360 scale)

Solomon NW(quadrangle 1:100,000 scale)

Nome(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Imuruk Basin(hydrologic unit)

Norton Sound(hydrologic accounting unit)

Northwest(hydrologic subregion)

Alaska(hydrologic region)

Geographic areas

Country	State
United States	Alaska

Commodities

Commodity	Importance
Graphite Critical	Primary

Materials information

Materials	Type of material
Graphite	Ore
Biotite	Gangue
Feldspar	Gangue
Garnet	Gangue
Quartz	Gangue
Sillimanite	Gangue

Host and associated rocks

Host or associated

Associated

Rock type

Plutonic Rock > Granitoid > Granite

Stratigraphic age (youngest)	Early Cambrian
Stratigraphic age (youngest)	Pliocene

Host or associated Host

Rock type Metamorphic Rock > Schist

Host or associated	Host
Rock type	Metamorphic Rock > Schist

Nearby scientific data

(1)	PzPxkg	ListMap

Economic information

Comments on the geologic information

Geologic Description = This is one of three graphite occurrences (this occurrence, NM023, and NM112) mapped by Hummel (1962 [MF 248]) in this part of the Kigluaik Mountains. At NM023, graphite with biotite is disseminated in schist and in segregations to 18 inches thick. It also occurs as sparse disseminations in pegmatite. Moffit (1913, p. 135-136) described a graphite-rich layer 8 inches thick between pegmatite and schist walls. This occurrence is probably also disseminations and segregations of graphite in schist.? the graphite-bearing rocks are upper amphibolite facies schist and gneiss that are probably derived from Precambrian protoliths (Sainsbury, 1972; Bunker and others, 1979; Till and Dumoulin, 1994). They are thought to have undergone regional high-pressure metamorphism along with many other rocks of Seward Peninsula in the Late Jurassic or Early Cretaceous (Sainsbury, Coleman, and Kachadoorian, 1970; Forbes and others, 1984; Thurston, 1985; Patrick, 1988; Patrick and Evans, 1989; Armstrong and others, 1986; Hannula and McWilliams, 1995). Higher temperature metamorphism overprinted these rocks in conjunction with regional extension, crustal melting, and magmatism in the mid-Cretaceous (Throckmorton and Hummel, 1979; Till, 1983; Evans and Patrick, 1987; Leiberman, 1988; Patrick and Leiberman, 1988; Miller and Hudson, 1991; Miller and others, 1992; Dumitru and others, 1995; Hannula and others, 1995; Hudson and Arth, 1983; Hudson, 1994; Amato and others, 1994; Amato and Wright, 1997, 1998). Uplift of the higher temperature metamorphic rocks took place in the mid- to Late Cretaceous and in the Eocene (Calvert, 1992; Dumitru and others, 1995).
Age = Mid-Cretaceous, the age of high-grade metamorphism.

Economic information about the deposit and operations

Development status	Occurrence
Commodity type	Non-metallic

Comments on exploration

Status = Inactive

Mining district

District name	Nome

Reference information

Links to other databases

Agency	Database name	Acronym	Record ID	Notes
USGS	Mineral Resources Data System	MRDS	A012967
USGS	Alaska Resource Data File	ARDF	NM113

Bibliographic references

Deposit

Moffit, F.H., 1913, Geology of the Nome and Grand Central quadrangles, Alaska: U.S. Geological Survey Bulletin 533, 140 p.
Deposit

Hummel, C.L., 1962, Preliminary geologic map of the Nome D-1 quadrangle, Seward Peninsula, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-248, 1 sheet, scale 1:63,360.
Deposit

Sainsbury, C.L., Coleman, R.G., and Kachadoorian, Reuben, 1970, Blueschist and related greenschist faces rocks of the Seward Peninsula, Alaska, in Geological Survey research 1970: U.S. Geological Survey Professional Paper 700-B, p. B33-B42.
Deposit

Sainsbury, C.L., 1972, Geologic map of the Teller quadrangle, Seward Peninsula, Alaska: U.S. Geological Survey Map I-685, 4 p., 1 sheet, scale 1:250,000.
Deposit

Bunker, C.M., Hedge, C.E., and Sainsbury, C.L., 1979, Radioelement concentrations and preliminary radiometric ages of rock in the Kigluaik Mountains, Seward Peninsula, Alaska: U.S. Geological Survey Professional Paper 1129-C, 12 p.
Deposit

Till, A.B., 1980, Crystalline rocks of the Kigluaik Mountains, Seward Peninsula, Alaska: University of Washington, Seattle, M.Sc. thesis, 97 p.
Deposit

Till, A.B., 1983, Granulite, peridotite, and blueschist: Precambrian to Mesozoic history of Seward Peninsula: Alaska Geological Society Journal, Proceedings of the 1982 Symposium on Western Alaska Resources and Geology, p. 59-65.
Deposit

Hudson, T.L., and Arth, J. G., 1983, Tin-granites of Seward Peninsula, Alaska: Geological Society of America Bulletin, v. 94, p. 768-790.
Deposit

Forbes, R.B., Evans, B.W., and Thurston, S.P., 1984, Regional progressive high-pressure metamorphism, Seward Peninsula, Alaska: Journal of Metamorphic Geology, v. 2, p. 43-54.
Deposit

Thurston, S.P., 1985, Structure, petrology, and metamorphic history of the Nome Group blueschist terrane, Salmon Lake area, Seward Peninsula, Alaska: Geological Society of America Bulletin, v. 96, p. 600-617.
Deposit

Armstrong, R.L., Harakal, J.E., Forbes, R.B., Evans, B.W., and Thurston, S.P., 1986, Rb-Sr and K-Ar study of metamorphic rocks of the Seward Peninsula and southern Brooks Range, Alaska, in Evans, B.W., and Brown, E.H., eds., Blueschists and eclogites: Geological Society of America Memoir 164, p. 184-203.
Deposit

Evans, B.W. and Patrick, B.E., 1987, Phengite 3-T in high pressure metamorphosed granitic orthogneisses, Seward Peninsula, Alaska: Canadian Mineralogist, v. 25, part 1, p. 141-158.
Deposit

Leiberman, J.E., 1988, Metamorphic and structural studies of the Kigluaik Mountains, western Alaska: Seattle, University of Washington, Ph.D. dissertation, 191 p.
Deposit

Patrick, B.E., 1988, Synmetamorphic structural evolution of the Seward Peninsula blueschist terrane, Alaska: Journal of Structural Geology, v. 10, p. 555-565.
Deposit

Patrick, B.E., and Leiberman, J.E., 1988, Thermal overprint on blueschists of the Seward Peninsula, the Lepontine in Alaska: Geology, v. 16, p. 1100-1103.
Deposit

Patrick, B.E., and Evans B.W., 1989, Metamorphic evolution of the Seward Peninsula blueschist terrane: Journal of Petrology, v. 30, p. 531-555.
Deposit

Miller, E.L., and Hudson, T.L., 1991, Mid-Cretaceous extensional fragmentation of a Jurassic-Early Cretaceous compressional orogen, Alaska: Tectonics, v. 10, p. 781-796.
Deposit

Miller, E.L., Calvert, A.T., and Little, T.A., 1992, Strain-collapsed metamorphic isograds in a sillimanite gneiss dome, Seward Peninsula, Alaska: Geology, v. 20, p. 487-490.
Deposit

Calvert, A.T., 1992, Structural evolution and thermochronology of the Kigluaik Mountains, Seward Peninsula, Alaska: Stanford Califronia, Stanford University, M.Sc. thesis, 50 p.
Deposit

Hudson, T.L. 1994, Crustal melting events in Alaska, in Plafker, G., and Berg, H. C., eds., The Geology of Alaska: Boulder, Colorado, Geological Society of America, The Geology of North America, v. G-1, p. 657-670.
Deposit

Amato, J.M., Wright, J.E., Gans, P.B., and Miller, E.L., 1994, Magmatically induced metamorphism and deformation in the Kigluaik gneiss dome, Seward Peninsula, Alaska: Tectonics, v. 13, p. 515-527.
Deposit

Dumitru, T.A., Miller, E.L., O'Sullivan, P.B., Amato, J.M., Hannula, K.A., Calvert, A.T., and Gans, P.B., 1995, Cretaceous to Recent extension in the Bering Strait region, Alaska: Tectonics, v. 14, p. 549-563.
Deposit

Hannula, K.A., Miller, E.L., Dumitru, T.A., Lee, Jeffrey, and Rubin, C.M., 1995, Structural and metamorphic relations in the southwest Seward Peninsula, Alaska; Crustal extension and the unroofing of blueschists: Geological Society of America Bulletin, v. 107, p. 536-553.
Deposit

Hannula, K.A., and McWilliams, M.O., 1995, Reconsideration of the age of blueschist facies metamorphism on the Seward Peninusla, Alaska, based on phengite 40Ar/39Ar results: Journal of Metamorphic Geology, v. 13, p. 125-139.
Deposit

Amato, J.M., and Wright, J.E., 1997, Potassic mafic magmatism in the Kigluaik gneiss dome, northern Alaska -- A geochemical study of arc magmatism in an extensional tectonic setting: Journal of Geophysical Research, v. B102, no. 4, p. 8065-8084.
Deposit

Amato, J.M., and Wright, J.E., 1998, Geochronologic investigations of magmatism and metamorphism within the Kigluaik Mountains gneiss dome, Seward Peninsula, Alaska, in Clough, J.G., and Larson, Frank, eds., Short Notes on Alaskan Geology 1997: Alaska Division of Geological and Geophysical Surveys Professional Report 118a, p. 1-21.

Comments on the references

Primary Reference = Hummel, 1962 (MF 248)

General comments

Subject category	Comment text
Deposit	Model Name = Graphite disseminations and segregations in amphibolite facies metamorphic rocks.

Reporter information

Type	Date	Name	Affiliation	Comment
Reporter	22-OCT-99	Hawley, C.C.	Hawley Resource Group
Reporter	22-OCT-99	Travis L. Hudson	Hawley Resource Group

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.

Unnamed (Cobblestone River)

Geologic information

Identification information

Geographic coordinates

Site location context

Geographic areas

Commodities

Materials 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

Reference information

Links to other databases

Bibliographic references

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Comments on the references

General comments

Reporter information

Beyond USGS

Maps centered on this site

Authoritative Alaska resources