Explained by Marti L. Miller and Bruce M. Gamble
On the choice of deposit models
Kuroko massive sulfide deposits as described by Singer (1986) are permissive in areas underlain by mixed assemblages that include basaltic to andesitic marine volcanic rocks and local felsic volcanic units.
On the delineation of permissive tracts
This tract is delineated on the basis of geology considered permissive for kuroko massive sulfide deposits; no mineral occurrences of this type are known in the region. The permissive rock types are marine volcanic assemblages of the Koyukuk terrane (Patton and Moll-Stalcup, 1996). These rocks constitute a mixed assemblage largely composed of Upper Jurassic(?) and Lower Cretaceous andesitic volcanic and volcaniclastic rocks, but which locally includes dacitic lava flows (T.K. Bundtzen, written commun., 1992).
Important examples of this type of deposit
No examples of kuroko massive sulfide deposits are known in west-central Alaska.
On the numerical estimates made
No attempt was made to estimate the number of undiscovered kuroko massive sulfide deposits in this tract.
Patton, W.W., Jr. and Moll-Stalcup, E.J, 1996, Geology of the Unalakleet quadrangle, west-central Alaska: U.S. Geological Survey Miscellaneous Investigations Map I-2559, scale 1:250,000.
Singer, D.A., 1986, Descriptive model of kuroko massive sulfide, in Cox, D.P., and Singer, D.A., eds., Mineral deposit models: U.S. Geological Survey Bulletin 1693, p. 189-190.