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Title: Lakeview uranium area, Lake County, Oregon - constraints on genetic modelling from a district-scale perspective

Thesis/Dissertation ·
OSTI ID:6013188

Extent-of-outcrop geologic mapping (1:12,000) on the Cox Flat 7.5-minute quadrangle establishes the stratigraphy and structure near the White King uranium mine, about 25 km northwest of Lakeview, Lake County, Oregon. Bedrock includes an Oligocene andesitic volcanic/sedimentary section, four late Oligocene rhyodacitic ignimbrite sequences, a late Oligocene/Miocene tuffaceous section, locally thick early to late Miocene basaltic flows, and an interbedded sequence of late Miocene (about 7-8 Ma old) felsic tuffs and thin basalt flows. Relatively intense down-to-the northeast normal faulting and southwestward stratal tilting resulted from a pre-Basin-and-Range extensional tectonic regime with an ENE least-principal stress orientation. This faulting and tilting began after the late Oligocene ignimbrite volcanism and before the spread of Coleman Rim-equivalent basalt flows. The interpreted geology constrains genetic models, resource estimates, and exploration strategies for uranium occurrences in the Lakeview area. Fault- and fracture-controlled hydrothermal uranium deposits are restricted to favorable stratigraphic horizons of the Miocene section with the important exception of porous and permeable upper portions of the late Oligocene section. Previous models have stressed the importance of intrusive rhyolite plug domes as sources of uranium and/or heat in ore genesis and targeted exploration efforts at dome contacts. Mass balance and other arguments show that an association with rhyolite domes is not a necessary criterion for ore formation or exploration.

Research Organization:
Stanford Univ., CA (USA)
OSTI ID:
6013188
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English