Explained by Marti L. Miller and Thomas K. Bundtzen
On the choice of deposit models
This tract contains numerous Cretaceous and Tertiary calc-alkaline stocks that may host plutonic porphyry Au deposits as described by Hollister (1992). It is a continuation of a tract defined for southwest Alaska.
On the delineation of permissive tracts
This tract trends northeast through the Ophir, Medfra, Nulato, and Ruby quadrangles, and is contiguous to the tract in the southwestern region. It is defined by the Kuskokwim Mountain belt, which features volcano-plutonic complexes (and related stocks), gold-quartz vein deposits, and favorable geochemical data (Bundtzen and Miller, 1997).
Important examples of this type of deposit
There are no known porphyry gold deposits in this tract; however, the contiguous tract in the southwest region contains several plutonic-related gold deposits including those at Chicken Mountain and Golden Horn (Bundtzen and others, 1992) in the Iditarod quadrangle, and at Vinasale Mt. (DiMarchi, 1993) in the McGrath quadrangle.
On the numerical estimates made
No estimate of the number of undiscovered porphyry gold deposits for this tract was attempted.
Bundtzen, T.K., and Miller, M.L., 1997, Precious metals associated with Late Cretaceous-early Tertiary igneous rocks of southwestern Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral deposits of Alaska: Economic Geology Monograph 9, p. 242-286.
Bundtzen, T.K., Miller, M.L., Laird, G.M., and Bull, K.F., 1992, Geology and mineral resources of Iditarod mining district, Iditarod B-4 and eastern B-5 quadrangles, southwestern Alaska: Alaska Division of Geological and Geophysical Surveys Professional Report 97, 46 p. scale 1:63,360 and 1:770.
DiMarchi, J.J., 1993, Geology, alteration, and mineralization of the Vinasale Mountain gold deposit, west-central Alaska, in Solie, D.N., and Tannian, Fran, eds., Short Notes on Alaskan Geology 1993: Alaska Division of Geological and Geophysical Surveys Professional Report 113, p. 17-29.
Hollister, V.F., 1992, On a proposed plutonic porphyry gold deposit model: Nonrenewable Resources, v. 1, no. 4, p. 293-302.