| Quadrangle map, 1:250,000-scale | MM |
|---|---|
| Quadrangle map, 1:63,360-scale | B-1 |
| Latitude | 63.3996 |
| Longitude | -150.2881 |
| Nearby scientific data | Find additional scientific data near this location |
| Location and accuracy | This record describes prospects on the Highlander (Lead No. 3) and Cleary (Nord) claims, herein referred to as the easternmost tier of claims of the part of the Mt. Eielson (Copper Mountain) district west of the Thorofare River. The location is the approximate center of the side line between the Highlander and Cleary claims; it is an elevation of about 3400 feet in the SW1/4NW1/4 sec. 32, T. 17 S., R. 14 W., Fairbanks Meridian. The location is probably accurate to 500 feet. |
Geologic descriptionThe deposits on the Highlander and Cleary claims are well exposed in the cliff faces above the Thorofare River, near the east end lines of the claims. On the Highlander claim, altered and fresh Paleozoic sedimentary rocks strike N 75 W, and dip about 50 N. These rocks are cut by many sills of porphyritic granodiorite (Reed, 1933, p. 283). A mineralized bed about 60 feet thick is exposed about in the middle of the east side line. A chip sample representing the best mineralized half of the bed assayed 0.01 ounce of gold and 1.50 ounces of silver per ton, 0.83 percent copper, 2.89 percent lead, and 5.57 percent zinc. A five-foot-thick band of ore is at the east side line of the Cleary claim. The best two feet of the band assayed 0.01 ounce of gold and 15.3 ounces of silver per ton, 0.78 percent copper, 4.22 percent lead, and 20.16 percent zinc (Reed, 1933, p. 283-284). The mineralization probably is Oligocene, roughly contemporaneous with the Eocene or Oligocene emplacement age of the granodiorite (Reed and Lanphere, 1974; Decker and Gilbert, 1978; Cole, 1998). | |
| Geologic map unit | (-150.290355282112, 63.3991083059338) |
|---|---|
| Mineral deposit model | Polymetallic replacement deposits; Pb-Zn skarn (Cox and Singer, 1986; models 19a; 18c). |
| Mineral deposit model number | 19a, 18c |
| Age of mineralization | The mineralization probably is Oligocene, roughly contemporaneous with the Eocene or Oligocene emplacement age of the granodiorite (Reed and Lanphere, 1974; Decker and Gilbert, 1978; Cole, 1998). |
| Alteration of deposit | Introduction of epidote and quartz into calcareous sedimentary rocks. |
| Workings or exploration | Sometime before 1931, the Highlander claim was staked by Hugh Matheson and the Cleary claim was staked by Ben Cleary. Shortly before World War II, these claims were restaked, respectively, as the Lead No. 3 and Nord (Muir, Thomas, and Sanford, 1947). They probably have not been active since about 1950. |
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| Indication of production | Undetermined |
Additional commentsThe claims are in Denali National Park and Preserve. | |
ReferencesCole, R. B., 1998, Early Tertiary post-subduction volcanism and deformation along the north side of the McKinley fault, Alaska [abs]: Geological Society of America. Abstracts with program, v. 30, p. 177.
Reed, B. L., and Lanphere, M. A., 1974, Offset plutons and history of movement along the McKinley segment of the Denali fault system, Alaska: Geological Society of America Bulletin, v. 85, p. 1883-1892.
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| Reporters | C.C. Hawley |
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| Last report date | 12/15/2000 |