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Geochemical Evolution Of Ferruginous Bauxite Deposits In Northwestern Oregon And Southwestern Washington, Joseph Michael Fassio
Geochemical Evolution Of Ferruginous Bauxite Deposits In Northwestern Oregon And Southwestern Washington, Joseph Michael Fassio
Dissertations and Theses
Ferruginous bauxite deposits developed from flows of the Columbia River Basalt Group in northwestern Oregon and southwestern Washington. Samples of the iron pisolite and the gibbsite nodular zones from the upper portion of the weathering profile of drill core from Columbia County, Oregon and Cowlitz County, Washington, were analyzed by instrumental neutron activation. The mineralogy was determined using Xray diffraction and Mossbauer spectroscopy.
The gibbsite nodular zone is above the clay-rich saprolite or relic basalt zone. The nodules contain relic vesicles and well preserved relic plagioclase microlites. Gibbsite occurs with poorly crystalline goethite and hematite in the gibbsite nodular zone. …