A SPATIAL INVESTIGATION OF METAL AND MINERAL ASSOCIATIONS IN THE MARCELLUS SHALE

In this study, Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) was used to map the elemental compositions of core and outcrop samples of the Marcellus Shale that were collected from western NY and PA. The elements of primary interest in this study included the metals uranium and chromium as well as oxygen, hydrogen and carbon. 2-D image maps produced from ToF-SIMS analyses were analyzed by ImageJ; a computer-based program that integrates hardware and software for managing, analyzing and displaying data. Six shale samples with total organic content between 3.13 and 8.55 wt% were analyzed. Uranium concentrations ranged from 8.7 to 53.4 ppm and chromium concentrations ranged from 53 to 120 ppm. Preliminary results indicate that chromium (Cr⁺) has little to no negative correlation to the hydrocarbons present in the samples with correlation coefficients (R) ranging from -0.06 to -0.25. The uranium species identified include UH⁺, U⁺, and UO^-. UH⁺ and U⁺ both show little to no negative or positive relationship with the hydrocarbons in the sample with correlation coefficients ranging from -0.1 to 0.22 and from -0.01 to 0.18, respectively. UO^- also shows little to no positive correlation with the hydrocarbons present in the sample with correlation coefficients ranging from 0.02 to 0.23. Correlation of uranium and chromium to clay minerals present in the samples will be explored.