Monarch

Prospect in Alaska, United States with commodities Iron, Gold, Manganese, Lead, Zinc

Geologic information

Identification information

Deposit ID 10094060
MRDS ID A012779
Record type Site
Current site name Monarch
Related records 10233513

Geographic coordinates

Geographic coordinates: -165.7783, 64.75178 (WGS84)
Relative position The Monarch prospect is at the head of an unnamed northwest-flowing tributary of the Sinuk River. It is mainly in the W1/2 section 33, T. 8 S., R. 35 W., Kateel River Meridian. It is 1.5 miles southwest of the Mogul prospect (NM020) and accurately located. It is locality 3 of Cobb (1972 [MF 463],1978 [OFR 78-93]).
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Iron Primary
Gold Secondary
Manganese Secondary
Lead Secondary
Zinc Secondary

Materials information

Materials Type of material
Goethite Ore
Hematite Ore
Limonite Ore
Pyrolusite Ore
Dolomite Gangue

Alteration

  • (Local) Dolomitization and oxidation.

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Metavolcanic Rock > Mafic Metamorphic Rock > Greenstone

Nearby scientific data

(1) -165.7783, 64.75178

Comments on the geologic information

  • Geologic Description = Iron and 11 percent manganese. The West Gap body seems to have more manganese. A representative sample of the East Gap body contained 78.30 percent ferric oxide (about 55 percent iron) and 1.37 percent manganese oxide (Eakin, 1915, p. 363). Soil samples collected here by Herreid (1970, table II, figure 4) locally are highly anomalous in lead and zinc. One sample at the basal marble contact below the West Gap zone contained 1,000 ppm zinc. Samples over the East Gap zone contain as much as 340 ppm lead and 1,200 ppm zinc. Sample 111 from West Gap contained 280 ppm lead. The prospect appears to lie along north-trending high-angle faults (Herried, 1970).? This prospect and other iron deposits of the Sinuk River area are at or near the base of massive marble whose protolith age is probably lower Paleozoic (Sainsbury, Hummel, and Hudson, 1972; Bundtzen and others, 1994). The deposits are locally controlled by high angle faults or folds, but they are in general crudely stratabound within the basal massive marble or underlying calc-schist (Mulligan and Hess, 1965; Herreid, 1970). This stratigraphic interval also hosts base metal sulfide-fluorite-barite deposits at the Galena (NM130) and Quarry prospects (NM135).? the origin and age of the iron deposits of the Sinuk River area are uncertain. The deposits may be, in part, gossan developed on oxidized sulfide deposits (Eakin, 1915 [B 622-I, p. 361-365]; Mertie, 1918 [B 662-I, p. 425-449]; Cathcart, 1922; Mulligan and Hess, 1965; Herreid, 1970). Several of the iron deposits, including American (NM014) and Monarch (NM017), are locally highly anomalous in zinc and lead. Arguing against a simple gossan origin is the paucity of diagnostic textures and structures in boxworks that would suggest derivation from specific sulfide minerals. Alternatively, these deposits could be hypogene iron oxide and carbonate deposits that are possibly transitional to some of the lead-zinc-barite (as at the Quarry prospect, NM135) deposits of the area.? the age of the iron deposits of the Sinuk River area is most likely post-mid-Cretaceous because faults that crosscut mid-Cretaceous metamorphic rocks are an important control. A Late Cretaceous age for the iron deposits was suggested by Brobst and others (1971) because this is the age of flourine-rich tin granites of northwestern Seward Peninsula (Hudson and Arth, 1983). The youngest possible age appears to be Early ?Tertiary, when deep weathering, sandstone-type uranium mineralization, and possibly karst formation occurred to the east in the Solomon quadrangle (Hudson, 1999).
  • Age = Late Cretaceous or Early Tertiary; post mid-Cretaceous metamorphism.

Economic information

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Comments on exploration

  • Status = Probably inactive

Mining district

District name Nome

Reserves and resources

  • Type In-situ
    Estimate year 1942
    Total resources 22,000mt ore
    Remarks Entry carried over from Old MRDS or added later (i.e. it did not originate in ARDF)
    Commodity Subtype Grade units Group Importance Year
    Iron Fe 40 wt-pct Iron Major 1942
  • Type In-situ
    Estimate year 1942
    Total resources 223,000mt ore
    Remarks Entry carried over from Old MRDS or added later (i.e. it did not originate in ARDF)
    Commodity Subtype Grade units Group Importance Year
    Iron Fe 20 wt-pct Iron Major 1942

Comments on the reserve resource information

  • Reserves = Shallit (1942; Mulligan and Hess, 1965, table 3) estimated that this prospect contains 50,000 long tons of 30 to 45 percent iron and about 500,000 tons of 15 to 25 percent iron. Most of the iron ore has only 1 percent or less of manganese, but Mulligan and Hess (1965, p. 14) cite one analysis indicating about 15 percent iron and 11 percent manganese. The West Gap body seems to have more manganese. A representative sample of the East Gap body contained 78.30 percent ferric oxide (about 55 percent iron) and 1.37 percent manganese oxide (Eakin, 1915, p. 363).

Comments on the workings information

  • Workings / Exploration = Open cuts, a shallow shaft, and a short adit were driven before 1914. There are at least 12 patented claims over this prospect (Mulligan and Hess, 1965).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A012779
USGS Alaska Resource Data File ARDF NM017

Bibliographic references

  • Deposit

    Eakin, H.M., 1915, Placer mining in Seward Peninsula: U.S. Geological Survey Bulletin 622-I, p. 366-373.

  • Deposit

    Cathcart, S.H., 1922, Metalliferous lodes in southern Seward Peninsula: U.S. Geological Survey Bulletin 722, p. 163-261.

  • Deposit

    Shallit, A.B., 1942, Report on Sinuk River iron-ore deposits, Seward Peninsula, Alaska: Alaska Territorial Department of Mines Minerals Investigation, 46 p., 2 maps, scales 1:31,250, 1:4,800.

  • Deposit

    Mulligan, J.J., and Hess, H.D., 1965, Examination of the Sinuk iron deposits, Seward Peninsula, Alaska: U.S. Bureau of Mines Open-File Report 8-65, 34 p.

  • Deposit

    Herreid, G.H., 1970, Geology and geochemistry of the Sinuk area, Seward Peninsula, Alaska: Alaska Division of Mines and Minerals Geologic Report 36, 61 p., 3 sheets, scale 1:42,000.

  • Deposit

    Brobst, D.A., Pinckney, D.M., and Sainsbury, C.L., 1971, Geology and geochemistry of the Sinuk River barite deposits: U.S. Geological Survey Professional Paper 750-D, p. D1-D8.

  • Deposit

    Sainsbury, C.L., Hummel, C.L., and Hudson, Travis, 1972, Reconnaissance geologic map of the Nome quadrangle, Seward Peninsula, Alaska: U.S. Geological Survey Open-File Report 72-326, 28 p., 1 sheet, scale 1:250,000.

  • Deposit

    Cobb, E.H., 1972, Metallic mineral resources map of the Nome quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-463, 2 sheets, scale 1:250,000.

  • Deposit

    Cobb, E.H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Nome quadrangle, Alaska: U.S. Geological Survey Open-File report 78-93, 213 p.

  • 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

    Hudson, T.L., 1999, Alaska Resource Data File, Solomon quadrangle: U.S. Geological Survey Open-File Report 99-573, 360 p.

  • Deposit

    Bundtzen, T.K., Reger, R.D., Laird, G.M., Pinney, D.S., Clautice, K.H., Liss, S.A., and Cruse, G.R., 1994, Progress report on the geology and mineral resources of the Nome mining district: Alaska Division of Geological and Geophysical Surveys, Public Data-File 94-39, 21 p., 2 sheets, scale 1:63,360.

Comments on the references

  • Primary Reference = Herreid, 1970

General comments

Subject category Comment text
Deposit Model Name = Carbonate-hosted, iron oxide deposit.

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