Award Date

5-1-2015

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Geoscience

First Committee Member

Pamela C. Burnley

Second Committee Member

Russell Malchow

Third Committee Member

Elisabeth Hausrath

Fourth Committee Member

Ralf Sudowe

Number of Pages

203

Abstract

Aerial gamma ray surveys have many applications in geology and science in general, such as locating mining prospects, defining radioactive plumes, and detecting nuclear weapons. Unfortunately there is currently no simple way to separate the natural gamma radiation of soil and rocks from that of contaminants such as radioactive plumes. This project used geochemical data (uranium, potassium and thorium concentrations) collected from national databases, private companies, and the NURE (National Uranium Resource Evaluation) Survey, to create forward models of exposure rates measured by aerial gamma ray surveys. We developed these techniques using an area in north central Arizona known as the Navajo Mines area, chosen for its optimal conditions for aerial gamma ray surveys and readily available survey data. Models based on geochemical analyses from databases were not found to be successful, in part due to lack of data for some units. Models based on NURE data sorted by geologic unit were successful at replicating the aerial gamma ray survey, though units with Uranium mineralization proved difficult. ASTER visualizations were effectively used to create subunits of similar exposure rate within the Chinle Formation which contains multiple lithologies. For alluvial units, models based on drainage basin were attempted with success. With these models we are developing techniques to estimate the natural radiation generated by the rocks and soils of an area, making aerial gamma ray surveys more effective.

Keywords

Aerial surveys; Gamma ray survey; Gamma rays; Geochemistry; Health physics; Radiation, Background; Radioactive; United States – Chinle Formation; Uranium

Disciplines

Geochemistry | Geology | Remote Sensing

Language

English


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