Old Smoky

Prospect in Alaska, United States with commodities Gold, Antimony

Geologic information

Identification information

Deposit ID 10002912
MRDS ID A015402
Record type Site
Current site name Old Smoky
Related records 10232996

Geographic coordinates

Geographic coordinates: -148.52693, 65.50967 (WGS84)
Relative position The Old Smoky prospect is 1/4 mile north of Money Knob, just north of the old town of Livengood; NW1/4 sec. 23, T. 8 N., R. 5 W., of the Fairbanks Meridian.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Gold Primary
Antimony Secondary

Materials information

Materials Type of material
Gold Ore
Stibnite Ore

Alteration

  • (Local) Most of the intrusive rocks and some of the sedimentary host rocks have experienced variable degrees of metasomatic hydrothermal alteration followed by lower temperature supergene alteration (Allegro, 1984, p. 4). Allegro (1984) described four types of hydrothermal alteration: 1) silicification, as partial to complete replacement of the host rock by a dense network of quartz veinlets generally localized along contacts between the intrusive and sedimentary rocks; 2) sericitization, as fine- to medium-grained white mica in selvages along quartz veins, as anastomosing sericite-opaque mineral veinlets, and as patchy to massive sericitic replacement of feldspar, ferromagnesium minerals and quartz; 3) deposition of trigonal nets of needle-like rutile often associated with secondary quartz and minor feldspar; and 4) epidote 1 sericite as a replacement of calcic plagioclase and ferromagnesian minerals resulting in massive aggregates, pseudomorphs, veins, and vug fillings of epidote commonly associated with sericite, opaque minerals, and quartz.

Host and associated rocks

  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Sandstone

Nearby scientific data

(1) -148.52693, 65.50967

Comments on the geologic information

  • Geologic Description = Trenching near the head of Olive Creek has exposed narrow, northwest-trending auriferous arsenopyrite-quartz veins in ferruginous quartzite near the intersection of an altered, porphyritic, biotite-monzonite dike, and a potassium feldspar-porphyry dike (Foster, 1968). Mineralization at the Old Smoky prospect is in Devonian sedimentary rocks composed of shale, argillite, fine-grained sandstone, and pebbly conglomerate (Allegro, 1984, p. 3). Narrow zones of thermal metamorphism occur along sheared contacts between these sedimentary rocks and hypabyssal igneous intrusive rocks (Allegro, 1984, p. 3). Similar felsic intrusive rocks throughout the Livengood Quadrangle have been potassium-argon dated at 58.0 to 88.8 m.y. (Turner and others, 1975).? Most of the intrusive rocks and some of the sedimentary host rocks have experienced variable degrees of metasomatic hydrothermal alteration followed by lower temperature supergene alteration (Allegro, 1984, p. 4). Allegro (1984) described four types of hydrothermal alteration: 1) silicification, as partial to complete replacement of the host rock by a dense network of quartz veinlets generally localized along contacts between the intrusive and sedimentary rocks; 2) sericitization, as fine- to medium-grained white mica in selvages along quartz veins, as anastomosing sericite-opaque mineral veinlets, and as patchy to massive sericitic replacement of feldspar, ferromagnesium minerals and quartz; 3) deposition of trigonal nets of needle-like rutile often associated with secondary quartz and minor feldspar; and 4) epidote +/- sericite as a replacement of calcic plagioclase and ferromagnesian minerals resulting in massive aggregates, pseudomorphs, veins, and vug fillings of epidote commonly associated with sericite, opaque minerals, and quartz.? Allegro's (1984) investigation and sample data reveal that the mineralization in the southern portion of the cut is localized along the contact zones between the biotite monzonite and the surrounding sedimentary rocks, and along a contact between biotite monzonite and feldspar porphyry. Channel and chip samples of arsenopyrite-stibnite quartz veins from these zones contained 1.0 to 29.8 ppm gold. Selected samples from the prospect contain 3 to 13 ppm gold as determined by atomic absorption, and 1.6 to 7.0 ppm gold as determined by fire assay-atomic absorption (Foster, 1968, p. 2).? Adjacent to the sheared contact zone, the intrusive rocks are either highly silicified with abundant rutile and some epidote, sericite, arsenopyrite, and monor stibnite, or contain epidote with sericite, rutilated quartz and arsenopyrite (Allegro, 1984, p. 6). Other rocks from the contact zone show intense supergene effects such as clay alteration, covellite and iron-oxides. In some cases these zones contain gold. Green scorodite is present throughout the mineralized areas.? In the northern section of the prospect, the most abundant mineralization is located along the contact area between the feldspar porphyry and a roof pendant of sandstone and shale (Allegro, 1984). A massive 1-meter-wide stibnite lens surrounded by a bleached sericite zone occurs along the northern contact of the roof pendant. Channel samples along this contact zone range from 0.5 to 4.3 ppm gold (Allegro, 1984, p. 6). Some gold is also associated with saprolitic zones in all the intrusive phases but these zones are not limited to shear zones or contacts (Allegro, 1984, p. 6).
  • Age = Felsic intrusive rocks throughout the Livengood Quadrangle, similar to those at the mineralized contact zone of the Old Smoky prospect, have been potassium-argon dated at 58.0 to 88.8 m.y. (Turner and others, 1975).

Economic information

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Tolovana

Comments on the workings information

  • Workings / Exploration = Some trenching and prospect pits that have been channel and chip sampled.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A015402
USGS Alaska Resource Data File ARDF LG014

Bibliographic references

  • Deposit

    Foster, R.L., 1968, Descriptions of the Ruth Creek, Lillian Creek, Griffin, Old Smoky, Sunshine No. 2, and Olive Creek lode prospects, Livengood District, Alaska: U.S. Geological Survey Open-File Report 68-104, 21 p.

  • Deposit

    Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Circle quadrangle, Alaska: U.S. Geological Survey Open-File Report 76-633, 72 p.

  • Deposit

    Allegro, G.L., 1984, Geology of the Old Smokey prospect, Livengood C-4 quadrangle: Alaska Division of Geological and Geophysical Surveys Report of Investigations 84-1, 10 p., 1 sheet, scale 1:120.

  • Deposit

    Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Livengood quadrangle, Alaska: U.S. Geological Survey Open-File Report 76-819, 241 p.

  • Deposit

    Cobb, E.H., 1972, Metallic mineral resources map of the Livengood quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-413, 2 sheets, scale 1:250,000.

Comments on the references

  • Primary Reference = Allegro, 1984

General comments

Subject category Comment text
Deposit Model Name = Gold-bearing shear zone at contact of hypabyssal intrusions into sediments.

Reporter information

Type Date Name Affiliation Comment
Reporter 04-MAY-1999 C.J. Freeman Avalon Development Corporation
Reporter 04-MAY-1999 J.R. Guidetti Schaefer Avalon Development Corporation