National mineral assessment tract AK-BR05 (Kipushi Cu-Pb-Zn)

Tract AK-BR05
Geographic region Brooks Range, AK
Tract area 49,825sq km
Deposit type Kipushi Cu-Pb-Zn
Deposit age Mississippian - Pennsylvanian


Explained by Jeanine M. Schmidt, Karen D. Kelley, Richard I. Grauch, Byron R. Berger, John W. Cady, Gregory T. Spanski, James E. Kilburn.
On the choice of deposit models
This Brooks Range tract is permissive for Kipushi-type deposits, as described by Cox and Bernstein (1986), because it has the appropriate geologic setting (a continental platform or shelf with continental or passive margin rifting) and host rocks (dolostone, shale and shallow-water or platform carbonate rocks) for the deposit model.
On the delineation of permissive tracts
This tract is defined by carbonate rocks of the Mississippian to Pennsylvanian Lisburne Group. These are mainly platform carbonates, with some slope and deeper-water lithologies. Rapid facies changes in the western part of the tract suggest an environment of extensional synsedimentary faulting. Where the environment of deposition is not known or indeterminate, carbonate rocks of possible shelf, slope, or deeper-water-facies are included.
Important examples of this type of deposit
There are no known examples of Kipushi-type deposits in this tract, but there are several such deposits in pre-Mississippian rocks elsewhere in the Brooks Range.
On the numerical estimates made
No grade and tonnage curves are available for Kipushi-type deposits; no attempt was made to estimate the number of undiscovered deposits.
Cox, D.P., and Bernstein, L.R., 1986, Descriptive model of Kipushi Cu-Pb-Zn, in Cox, D.P., and Singer, D.A., eds., 1986, Mineral deposit models: U.S. Geological Survey Bulletin 1693, p. 227.
Schmidt, J.M., 1997b, Strata-bound carbonate-hosted Zn-Pb and Cu deposits of Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 90-119.

Geographic coverage

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