National mineral assessment tract AK-SC26 (Polymetallic replacement)

Tract AK-SC26
Geographic region South Central, AK
Tract area 4,445sq km
Deposit type Polymetallic replacement
Deposit age Mesozoic - Tertiary

Rationale

Explained by Marti L. Miller, Bruce M. Gamble, and Thomas D. Light
On the choice of deposit models
In south-central Alaska and nearby parts of southwestern, west-central, and east-central Alaska, carbonate rocks that are locally intruded by small felsic plutons may host polymetallic replacement deposits as described by Morris (1986).
On the delineation of permissive tracts
The areas permissive for polymetallic replacement deposits are defined by Paleozoic carbonate rocks, belonging to the Nixon Fork and Minchumina terranes, that are locally intruded by Late Cretaceous and Tertiary plutons (Patton and others, 1994). This tract is a continuation of adjacent tracts in southwestern, east-central, and west-central Alaska.
Important examples of this type of deposit
No examples of polymetallic replacement deposits are known in this tract.
On the numerical estimates made
No estimate of undiscovered resources was attempted.
References
Morris, H.T., 1986, Descriptive model of polymetallic replacement deposits, in Cox, D.P., and Singer, D.A., eds., Mineral deposit models: U.S. Geological Survey Bulletin 1693, p. 99-100.
Patton, W.W., Jr., Box, S.E., Moll-Stalcup, E.J., and Miller, T.P., 1994, Geology of west-central Alaska, in Plafker, George, and Berg, H.C., eds., The Geology of Alaska: Boulder, Colorado, Geological Society of America, The Geology of North America, v. G-1, p. 241-269.

Geographic coverage

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