Dakli Occurrence, Shungnak Mining District, Yukon-Koyukuk Census Area, Alaska, USAi

Regional Level Types
Dakli Occurrence	Occurrence
Shungnak Mining District	Mining District
Yukon-Koyukuk Census Area	Census Area
Alaska	State
USA	Country

Location: This occurrence is at an elevation of about 3,000 feet on the Continental Divide in section 14, T. 11 N., R. 12 E., of the Kateel River Meridian. Cobb (1972, MF-448), locations 8, 9, 10 and Miller and Ferrians (1968), figure 3.
Geology: The Dakli occurrence is at the northern edge of the Zane Hills pluton at the contact between Cretaceous hornblende-biotite granodiorite and Jurassic-Cretaceous andesite. According to Miller and ferrians (1968), copper and other minerals occur at three places along the contact . At locality 1, massive chalcopyrite in fractured quartz occurs in frost-riven blocks of meta-andesite. Pyrite, malachite, and covellite are also present. Grab samples of chalcopyrite in quartz contain as much as 150 ppm Ag, 0.8 ppm Au, 10,000 ppm Cu, 150 ppm Mo, and 1,000 ppm Zn. Several streams near this locality have meta-andesite float that is cut by sulfide-bearing quartz veins and contains disseminated sulfides. At locality 2, malachite and limonitic chalcopyrite occur in fractures in blocks of brecciated quartz, andesite and altered granodiorite in a zone 100 feet wide. Grab samples from this location contain as much as 30 ppm Ag, 0.09 ppm gold, 700 ppm Zn, 70 ppm Mo, and from 1,000 to 20,000 ppm Cu. At locality 3, a sample of sulfide-bearing quartz contained 1,000 ppm Cu, 2 ppm Ag, and 15 ppm Mo. At locality 4, about one mile south of the contact, rusty-colored molybdenite-bearing quartz veins as much as 2 feet thick cut the andesite near the granodiorite contact. A grab sample from one vein contained 2,000 ppm Mo. Sediments in streams draining the Dakli occurrence contain anomalous values of copper ranging from 100 to 300 ppm. The intrusives and volcanics both show little or no hydrothermal alteration. Copper and traces of molybdenum minerals are essentially restricted to the contact between the granodiorite and andesite and to the quartz veins within the contact area (unpublished industry data, NANA Regional Corp. files).
Workings: This occurrence was mapped by the U.S. Geological Survey in the mid 1960's (Miller and Ferrians, 1968). Numerous rock and stream sediment samples were collected and analyzed. A number of exploration companies examined the site during reconnaissance geologic programs in the 1970's and early 1980's.
Age: Cretaceous or younger.
Alteration: Oxidation of pyrite and chalcopyrite to limonite and secondary copper minerals.

Commodities (Major) - Ag, Au, Cu
Development Status: None
Deposit Model: Disseminated and massive sulfides in quartz veins cutting andesite and granodior

Other Databases

Link to USGS - Alaska:	SH004

Other Regions, Features and Areas containing this locality

References