Date of Award


Degree Name

Master of Arts



First Advisor

Dr. Stanley K. Derby

Second Advisor

Dr. Robert Poel

Third Advisor

Dr. John Grace

Access Setting

Masters Thesis-Open Access


A spectrographic analysis was conducted on ten granite samples of different geological origin from the Pioneer Mountains in Central Idaho. A qualitative analysis was performed first and then a quantitative analysis to determine the presence and relative amounts of copper in the various samples. This spectrographic analysis employed a direct current arc source of 340 volts and 4 amperes to excite the samples which were dissolved in acid and dried on the ends of high purity carbon electrodes. The emitted light passed through a step sector and a medium quartz spectrograph to a photographic plate. The optical density of the spectral lines on the photographic plate was determined with a microdensitometer. The optical density is related to the percentage of copper present in the rock samples. In order to compensate for many uncontrolled variables which could alter the optical line density, an internal control element, indium, was added to each sample. By comparing the copper line density to the internal control line density the influence of such variables as sample mass, exposure time, or slit width is controlled. The analysis of the ten samples found that the copper content varied from approximately 25 parts per million to 400 part per million.

This information augments and confirms previous analytical and geological knowledge concerning these granite samples from the Pioneer Mountains.

Included in

Optics Commons