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Reinisch (Arsenic Hill)

Prospect in Alaska, United States with commodities Gold, Silver
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Geologic information

Identification information

Deposit ID 10001989
MRDS ID A012833
Record type Site
Current site name Reinisch (Arsenic Hill)

Geographic coordinates

Geographic coordinates: -165.42495, 64.61372 (WGS84)
Relative position This lode prospect is on the same low knoll, locally called Arsenic Hill, along the west side of Rock Creek as the Rock Creek bench placer (NM210). Cathcart (1922, p. 245) described the location as opposite the mouth of Sophie Gulch. It is 3,400 feet due east of the Snake River road and about 1.6 miles south-southwest of Mount Byrnteson. Rock Creek is an east tributary to Snake River with headwaters on the south flank of Mount Byrnteson. The map location is midway between the 250- and 300-foot contours, just inside the north boundary of section 23, T. 10 S., R. 34 W., Kateel River Meridian. The prospect was included in locality 43 of Cobb (1972 [MF 463], 1978 [OFR 78-93]) and is locality 15 of Hummel (1962 [MF 247]).
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Gold Primary
Silver Secondary

Comments on the commodity information

  • Gangue = graphitic carbon

Materials information

Materials Type of material
Arsenopyrite Ore
Gold Ore
Hematite Ore
Limonite Ore
Pyrite Ore
Scorodite Ore
Albite Gangue
Calcite Gangue
Quartz Gangue

Alteration

  • (Local) Albitization; sulfidization (especially introduction of arsenopyrite); and oxidation of arsenopyrite.

Mineral occurrence model information

Model code 273
USGS model code 36a
Deposit model name Low-sulfide Au-quartz vein
Mark3 model number 27

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Schist

Nearby scientific data

(1) -165.42495, 64.61372
ListMap

Comments on the geologic information

  • Geologic Description = Cathcart (1922, p. 245) reported free gold in vuggy crystalline quartz in quartz-muscovite-graphite schist at this locality, which he described as a hydraulic pit (Reinisch) on a bench opposite Sophie Gulch. In recent years this bench has been called Arsenic Hill. The name apparently was applied in the 1980s by geologist R.V. Bailey to abundant exposures rich in arsenopyrite and its oxidation products, hematite, limonite, and scorodite.? Arsenic Hill is the low rounded ridge opposite the mouth of Sophie Gulch on the west side of Rock Creek. The crest of the ridge is at an elevation of about 280 feet. It is underlain by moderately resistant quartz-mica schist. Northeast-striking sheeted quartz veins are as much as one-half foot thick. The veins are spaced about 3 to 5 feet apart near the top of the ridge.? Southwest of the crest of Arsenic Hill, the quartz-mica schist appears to be much more altered and only locally crops out. This area was explored by Placer Dome trench 87-1, which cuts northwest across the ridge, and by Kennecott Exploration Company trench 94-8, which trends northeasterly subparallel to the sheeted vein structure. The Kennecott trench cuts across fold- and possibly fault-controlled mineral zones in schist that mainly contain arsenopyrite, which has been extensively oxidized to scorodite, hematite, and limonite. Sheeted veins cut across the northwest-aligned arsenopyrite-rich zones. Albite is locally abundant in the northwest-aligned structures. Sheeted veins exposed near the southwest end of trench 94-8 are deformed, apparently by recent slump and creep. The Arsenic Hill deposit explored by Placer Dome and Kennecott Exploration Company contains little gold.? the quartz-mica schist of Arsenic Hill is cut off on the southeast by the Arsenic Hill fault, a structure that crosses the ridge at an elevation of about 230 feet. Where exposed in trenches and subcrops, the fault locally contains graphitic zones with crystalline quartz, apparently similar to the gold-bearing rocks originally described by Cathcart (1922). Rocks southeast of the fault are relatively soft, graphitic calc-mica schist and resistant graphitic quartz schist. This graphitic schist is bounded to the northwest by the Arsenic Hill fault and to the northeast by the Sophie Gulch fault.
  • Age = Mid-Cretaceous; veins cross cut regionally metamorphosed schist; see NM207. The earliest albite- and arsenopyrite-rich replacement deposits at Arsenic Hill are along ductile folds in the host schist. Sheeted, non-deformed quartz veins cut the deposits along the ductile folds.

Economic information

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Comments on exploration

  • Status = Active?

Mining district

District name Nome

Comments on the workings information

  • Workings / Exploration = Placer gold was produced from the elevated bench deposit on the south end of the ridge (NM210); badly sloughed pits and shallow trenches reflect exploration before about 1920. The area has been explored, especially by trenching, sequentially since the 1980,s by R.V. Bailey, Placer Dome, and Kennecott Exploration Company.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A012833
USGS Alaska Resource Data File ARDF NM213

Bibliographic references

  • Deposit

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

  • Deposit

    Hummel, C.L., 1962, Preliminary geologic map of the Nome C-1 quadrangle, Seward Peninsula, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-247, 1 sheet, scale 1:63,360.

  • 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.

Comments on the references

  • Primary Reference = This report

General comments

Subject category Comment text
Deposit Model Name = Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a).

Reporter information

Type Date Name Affiliation Comment
Reporter 10-JUL-00 Hawley, C.C. Hawley Resource Group
Reporter 10-JUL-00 Travis L. Hudson Hawley Resource Group