Date of Graduation

Fall 2018

Degree

Master of Science in Geospatial Sciences

Department

Geography, Geology, and Planning

Committee Chair

Gary Michelfelder

Keywords

method development, chemical image analysis, ToF-SIMS, diamond geochemistry, stable isotope geochemistry

Subject Categories

Geochemistry | Geology | Materials Chemistry | Mineral Physics

Abstract

The chemical resistance of diamond allows in-situ study of the diamond source regions. For a majority of gem quality diamonds, this source region is the sublithospheric mantle keel of a cratonic nuclei. Through analysis of stable isotopes, radiogenic isotopes and trace elements, diamond geochemical analyses can define chemical fluxes in the mantle keel. However, such studies require multiple methodologies for each chemical suite, high spatial resolution and analytical precision. Here, I evaluate Time-of-Flight Secondary Ionization Mass Spectrometer (ToF-SIMS) as an alternative method for diamond geochemical analyses. ToF-SIMS analysis can perform in cation and anion mode to measure the entire periodic table of an analyte. Establishing a quantitative ToF-SIMS methodology would dramatically increase the accessibility of diamond geochemical analyses. I determine the feasibility of developing such a ToF-SIMS diamond geochemical methodology. For ToF-SIMS to be considered a plausible method, ToF-SIMS needs to replicate established instrumentation spatial resolution and analytical precision. I determine that ToF-SIMS is able to replicate established spatial resolutions with single pixels in our element maps being < 2 μm2.Through measurements of 13C and 12C, I show that ToF-SIMS is unable to replicate the analytical precision necessary for δ13C values. I conclude by establishing a framework for future ToF-SIMS studies to the end of obtaining the necessary analytical precision for quantifying isotopic variation and improved mass resolution.

Copyright

© Tyler J. Sundell

AR transects.xlsx (257 kB)
Image transects of diamond AR

AR Carbon and Oxygen.xlsx (9478 kB)
Raw Oxygen and Carbon data file for diamond AR

SL-1 Transects.xlsx (444 kB)
Image transects of diamond SL-1

SL-1 Carbon and Oxygen.xlsx (17422 kB)
Raw Oxygen and Carbon data file for diamond SL-1

SL-2 Transects.xlsx (442 kB)
Image transects of diamond SL-2

SL-2 Carbon and Oxygen.xlsx (17260 kB)
Raw Oxygen and Carbon data file for diamond SL-2

SL-4 Transects.xlsx (378 kB)
Image transects of diamond SL-4

SL-4 Carbon and Oxygen.xlsx (14379 kB)
Raw Oxygen and Carbon data file for diamond SL-4

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