| alteration: | The alteration at Johnson River can be divide into two main events. An early stage of nodular anhydrite and fine-grained disseminated pyrite is accompanied by Mg-chlorite, sericite, monmorillonite and or calcite. This alteration is either barren or weakly anomalous in base metal mineralization. The later alteration consists of silicification and sulfidation accompanied by iron-chlorite, sericite, barite, carbonate, and vein anhydrite. This stage alteration includes all the mineralization at Johnson River (Steefel, 1987). |
| References: |
- Deposit:: Detterman, R.L., Reed, B.L., and Lamphere, A.A., 1965, Jurassic plutonism in the Cook Inlet region, Alaska: U.S. Geological Survey Professional Paper 525-D, p. D16-D21.
- Deposit:: Detterman, R.L., and Hartsock, J.L., 1966, Geology of the Iniskin-Tuxedni region, Alaska: U.S. Geological Survey Professional Paper 512, 78 p.
- Deposit:: Steefel, C.I., 1987, The Johnson River Prospect, Alaska: Gold rich sea-floor mineralization from the Jurassic: Economic Geology, V. 82, p. 894-914.
- Deposit:: Nokleberg, W.J., Bundtzen, T.K., Berg, H.C., Brew, D.A., Grybeck, D.J., Robinson, M.S., Smith, T.E., and Yeend, W., 1987, Significant metalliferous lode deposits and placer districts of Alaska: U.S. Geological Survey Bulletin 1786, 104 p.
- Deposit:: Swainbank, R.C., Bundtzen, T. K., Clough A.H., and Henning, M.W., 1997, Alask* mineral industry 1996: Alaska Division of Geological and Geophysical Surveys Special Report 51, 68 p.
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