Babybasket Occurrence, McGrath District, Yukon-Koyukuk Borough, Alaska, USA

Similar deposits are described in the McGrath and Lime Hills quadrangles (Bundtzen and others, 1994; 1997).
Location: The Babybasket occurrence is situated just south of the highest point in the Babybasket Hills (1,455 ft summit) at an elevation of 1,250 feet (381 m) in Section 36, T. 27 S., R. 26 E., of the Kateel River Meridian. Location is imprecise and judged to within a two mile (3.2 km) radius.
Geology: The Babybasket prospect consists of several zones of disseminated chalcopyrite, pyrite and rare sphalerite in calc-silicate skarn and carbonate replacement zones. The mineralized zones are adjacent to gabbro-diorite dikes and sills that intrude Cambro-Ordovician silty limestone and shale of the Lyman Hills Formation, the lower-most part of the Dillinger subterrane as defined by Bundtzen and others (1997). No size or orientations of mineralized zones are known. The occurrences were detected as a result of anomalous values found in stream sediment and pan concentrate samples collected by the U.S. Geological Survey (King and others, 1980; 1983). Age is probably either Paleozoic or Triassic, based on isotopic age data collected from equivalent gabbro-diorite sills in the McGrath quadrangle (Bundtzen and others, 1997).
Workings: The Babybasket occurrence was found as the result of sampling by the U.S. Geological Survey (King and others, 1980; 1983).
Age: The Babybasket occurrence is probably either Paleozoic or Triassic, based on isotopic age data collected from equivalent gabbro-diorite sills in the McGrath quadrangle (Bundtzen and others, 1997).
Reserves: None.

Commodities (Major) - Cu, Zn; (Minor) - Ag, Pb
Development Status: No
Deposit Model: Polymetallic Replacement Deposit (?)(Cox and Singer, 1986; model no. 19a)

References:
Bundtzen, T.K., Harris, E.E., and Gilbert, W.G., 1997, Geologic Map of the eastern McGrath quadrangle, Alaska: Alaska Division of Geological and Geophysical Surveys Report of Investigations 97-14, 34 p., 1 sheet, scale 1:125,000. Bundtzen, T.K., Laird, G.M., Harris, E.E., and Clautice, K.H., 1994, Geologic map of the Lime Hills C-5 and C-6 quadrangles, Alaska: Alaska Division of Geological and Geophysical Surveys Public Data File Report 94-40, 30 p., 1 sheet, scale 1:63,360. King, H.D., Cooley, E.F., and Spiesman, D.L., 1983, Distribution of gold and silver in nonmagnetic and magnetic heavy mineral concentrate and minus 80 mesh stream sediment samples and ash of aquatic bryophyte samples, Medfra quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-811K. King, H.D., Risoli, D.A., Cooley, E.F., O'Leary, R.M., Speckman, W.A., Speisman, D.L., and Galland, D.W., 1980, Final results and statistical summary of analyses of geochemical samples from the Medfra quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-811F, 134 pages.