National mineral assessment tract AK-EC20 (Zn-Pb skarn)

Tract AK-EC20
Geographic region East Central, AK
Tract area 29,265sq km
Deposit type Zn-Pb skarn
Deposit age Mesozoic - Tertiary


Explained by Bruce M. Gamble, Marti L. Miller, and Thomas D. Light
On the choice of deposit models
The presence of intermediate to felsic plutonic rocks that may intrude carbonate-bearing units suggests that this tract is permissive for Zn-Pb skarn deposits as described by Cox (1986).
On the delineation of permissive tracts
This tract is defined by the distribution of carbonate rocks and possible carbonate-bearing units and by the known or inferred presence of intermediate to felsic plutonic rocks (Patton and others, 1994; Nokleberg and others, 1994). Known mineral deposits in the adjacent tract in west-central Alaska include a Cu-Au skarn and a Fe-skarn.
Important examples of this type of deposit
No Zn-Pb skarn deposits are known in this tract.
On the numerical estimates made
Because of the lack of detailed geologic information, no estimates of the number of undiscovered deposits have been attempted.
Cox, D.P., 1986, Descriptive model of Zn-Pb skarn deposits, in Cox, D.P., and Singer, D.A., eds., Mineral deposit models: U.S. Geological Survey Bulletin 1693, p. 90.
Nokleberg, W.J., Moll-Stalcup, E.J., Miller, T.P., Brew, D.A., Grantz, Arthur, Reed, J.C., Jr., Plafker, George, Moore, T.E., Silva, S.R., and Patton, William W., Jr., 1994, Tectonostratigraphic terrane and overlap assemblage map of Alaska: U.S. Geological Survey Open-File Report 94-194, 45 manuscript p., scale 1:2,500,000.
Patton, W.W., Jr., Box, S.E., and Grybeck, D.J., 1994, Ophiolites and other mafic-ultramafic complexes in Alaska, in Plafker, George, and Berg, H.C., eds., The Geology of Alaska: Boulder, Colorado, Geological Society of America, The Geology of North American, v. G-1, p. 671-686.

Geographic coverage

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