Khotol Ridge

Occurrences, Probably inactive

Alternative names

Sunny Day
Honkette

Commodities and mineralogy

Main commodities Pb; Zn
Other commodities Ag; Au; Cu
Gangue minerals limonite

Geographic location

Quadrangle map, 1:250,000-scale NL
Quadrangle map, 1:63,360-scale A-4
Latitude 64.2
Longitude -157.8
Nearby scientific data Find additional scientific data near this location
Location and accuracy This site consists of three small occurrences of gossan in the vicinity of Khotol Mountain. They are informally called Khotol Ridge, Sunny Day, and Honkette. They share similar geologic characteristics and are a mile or so apart. The coordinates are for the approximate location of the Khotol Ridge gossan, at an elevation of 1900 feet on the northwest flank of hill 2047, a northeast-trending ridge of Khotol Mountain. It is in the NW1/4 sec. 23, T. 15 S., R. 5 E., Kateel River Meridian. This location is accurate within 2 miles. The Sunny Day gossan is 1.65 miles south-southwest of the Khotol Ridge gossan, and the Honkette gossan is 1.15 miles west-southwest of it.

Geologic setting

Geologic description

The Khotol Ridge gossan is associated with biotite granite of the Khotol pluton, quartz-mica schist, quartzite, and minor graphitic schist. A transitional phase of quartz-eye biotite schist occurs along the contact between the Khotol pluton and the quartz-mica schist. This quartz-mica schist overlies the quartzite, strikes northeast, and dips approximately 40 degrees southeast. The quartzite resembles that at the nearby Illinois Creek mine (NL023) and commonly contains euhedral limonite pits after pyrite. The quartzite unit can be traced nearly continuously for over 10 km from hill 1677 (NL015) southwest through the Sunny Day gossan to just south of the Honker prospect (NL018). Grab and soil samples at Khotol Ridge contain up to 231 ppm copper, 6750 ppm lead, 1190 ppm zinc, 16 ppm silver, 3600 ppm manganese, 850 ppm arsenic, and 40 ppb gold (Flanigan, 1998).
The Sunny Day gossan consists of scattered limonite-quartzite breccia and minor massive, vuggy, gossan float. It is in an east-west trending gully coincident with an airphoto lineament. Quartzite in this area is similar to quartzite at Illinois Creek (NL023) and Khotol Ridge. Several soil, rock, and stream samples are only weakly mineralized, with values up to 3.0 ppm silver, and less than 1000 ppm arsenic (Flanigan, 1998). The Honkette gossan consists of a linear zone of millimeter- to centimeter-scale limonite veinlets in dark-gray andalusite hornfels. These veinlets are similar to veinlets in the wall rocks at the Honker prospect (NL018) (Flanigan, 1998).
Flanigan (1998) interprets these gossans to be related to magmatic fluids from the Khotol pluton, based on their proximity to the pluton and their low molybdenum content . K-Ar and Ar/Ar dates for the Khotol pluton are approximately 110 Ma (Flanigan, 1998).
Also see NL012-014, 016, and 019-022.
Geologic map unit (-157.802445817821, 64.1993482128338)
Mineral deposit model Pb-Zn gossan; pluton-related epigenetic?
Age of mineralization Flanigan (1998) interprets these gossans to be related to magmatic fluids from the Khotol pluton, based on their proximity to the pluton and their low molybdenum content . K-Ar and Ar/Ar dates for the Khotol pluton are approximately 110 Ma (Flanigan, 1998).
Alteration of deposit Locally conspicuous iron-oxide alteration.

Production and reserves

Workings or exploration These occurrences were discovered by Anaconda Minerals Company in 1982 (Flanigan, 1998).
Indication of production None

References

MRDS Number 10307895

References

Flanigan, B., 1998, Genesis and mineralization of ore deposits in the Illinois Creek region, west central Alaska: University of Alaska, Fairbanks, M.Sc. thesis, 125 p., 2 plates.
Reporters C.E. Cameron (Northern Associates Inc.)
Last report date 8/7/2001