|Quadrangle map, 1:250,000-scale||MM|
|Quadrangle map, 1:63,360-scale||D-4|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This occurrence is on the west side of the range of low hills that extends north from Chilchukabena Lake. The location is approximately at the midpoint of the boundary between sections 6 and 7, T 11 S., R. 20 W., Fairbanks Meridian. It is probably accurate within about 1000 feet. The location correponds to that of rock samples 5 and 6 of Hawley and Associates (1978).|
A stock of McKinley-type granite (Reed and Lanphere, 1973) forms hills north of Chilchukabena Lake. The outcrop of the stock is about 3 miles long and 1.3 miles across; a small granite cupola crops out northeast of the stock. Only the approximate southern two-thirds of the stock is in the Mt. McKinley quadrangle.
In 1975, Hawley and Associates (1978) made an airborne radiometric survey of the area using a hand-held spectrometer. The aircraft flew about 150 feet above the ground at 90 miles per hour. Background radiation over the granite mass was relatively high, partly due to its potassium feldspar content, but the radiation level was more than twice background over the cupola. Hawley and Associates collected samples of slightly altered, fine- and coarse-grained granite on the south side of the stock (the location of this occurrence). The samples contained up to 50 ppm lead, 200 ppm zinc, 20 ppm beryllium, and 10 ppm tin.The granite at this site resembles the granite that hosts beryllium and base-metal prospects in the Boulder Creek or Tonzona area west of the old park boundary (Hawley and Associates, 1978, p. 4,124-126).
|Geologic map unit||(-151.54974844255, 63.982375229698)|
|Mineral deposit model||Weakly-altered tin? granite.|
|Age of mineralization||The stock is tentatively correlated with McKinley-type granite, which is about 55 Ma (Reed and Lanphere, 1973).|
|Alteration of deposit||Weak argillic(?) alteration.|
|Workings or exploration||Hawley and Associates (1978) conducted an airborne radiometric survey and reconnaissance-sampled the stock.|
|Indication of production||None|
Additional commentsThe south part of the granite stock is in Denali National Park and Preserve.
Hawley, C. C. and Associates, Inc, 1978, Mineral appraisal of lands adjacent to Mt. McKinley National Park, Alaska: U. S. Bureau of Mines Open-File Report 24-78, 275 p. (paged by sections).
Reed, B.L., and Lanphere, M.A., 1973, Alaska-Aleutian Range batholith--Geochronology, chemistry, and relation to circum-Pacific plutonism: Geological Society of America Bulletin, v. 84, no. 8, p. 2583-2610.
|Last report date||5/7/2001|