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dc.contributor.authorLessard, Richard R.
dc.date.accessioned2016-09-28T21:05:59Z
dc.date.available2016-09-28T21:05:59Z
dc.date.issued2006-12
dc.identifier.urihttp://hdl.handle.net/11122/6918
dc.descriptionThesis (M.S.) University of Alaska Fairbanks, 2006en_US
dc.description.abstractThe Caribou Creek area, in the Big Delta C4 Quadrangle, East-Central Alaska, is known for significant placer gold, but no lode source. I present a new 200 km² area geologic map utilizing ground based mapping, airborne geophysical surveys, and follow-up laboratory investigations. Mapping and petrography delineate 10-20 km² blocks containing contrasting rock units and mineral assemblages. Amphibolite facies blocks contain abundant post-kinematic andalusite, with central blocks containing partially replaced kyanite, and blocks to the southeast and west containing post-kinematic sillimanite. Geothermobarometry shows that the amphibolite-facies blocks experienced pressures/temperatures of 11.5 kbars/650°C, followed by a collisional event associated with low-P/variable T post-kinematic recrystallization. The distribution of alumino-silicates suggests the central blocks were down dropped relative to adjacent blocks. Gold occurrences are found in west to northwest trending, steeply dipping quartz veins with stibnite ± arsenopyrite. Located in the central blocks, they are separated from a barren granodiorite pluton by a sinistral, northeast trending, high-angle fault. This study has shown the existence of major faults with significant vertical and horizontal movement, making gold source determination difficult. Future lode gold exploration in the area must take the high-angle faulting into consideration.en_US
dc.description.tableofcontents1. Introductions and geologic setting -- 2. Overview of rock types and structure -- 3. Igneous and meta-igneous rocks -- 4. Lower grade metamorphic rocks -- 5. Medium-grade metamorphic rocks -- 6. Characterization and distribution of metamorphic P-T conditions -- 7. Mineralization -- 8. Discussions and conclusions -- References.en_US
dc.language.isoen_USen_US
dc.titleGeology of the Caribou Creek area, Big Delta quadrangle, east-central Alaskaen_US
dc.typeThesisen_US
dc.type.degreemsen_US
dc.identifier.departmentDepartment of Geology and Geophysicsen_US
refterms.dateFOA2020-01-25T02:15:41Z


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