Katie Snodgrass
IUUR STEM Summer Research Program
Major: Earth Science
Mentor: Shelby Rader
Platinum group elements (PGE) are important for a wide variety of uses including industrial, medical, electronic, as well as jewelry production, making them an important prospect for materials such as catalytic converters, phones, laptops, rubber, and nylon to name a few. An inactive mine that lies in southeastern Wyoming, known as the New Rambler Mine, is notorious for containing an abundance of PGE mineralization within ore samples. PGE mineralization usually occurs during magmatic differentiation-a chemical change in the composition of magmas; however, these samples are unique in terms of their history. The hypothesis for this phenomenon is that a series of shear zones (a type of displacement of Earth’s crust) allowed for hydrothermal fluids to remobilize and weather material from the surface, causing unusually high concentrations of PGEs. This is an unusual control on PGE mineralization. Upon receiving samples from a historical collection, they were crushed, submitted to a series of acid baths over a hot plate to break any bonds within the sample, diluted at 1,000x and 100,000x with 2% nitric acid, and run through a machine for a process known as ICP-MS (inductively coupled plasma mass spectrometry). The dilution step is vital to ensure that both trace elements and more abundant elements are accurately detected. This instrument calculates the concentrations of the elements present within a sample- including PGE elements. The data collected confirms that PGEs are abundant in the samples collected from the New Rambler Mine. It is apparent that copper hydroxide and copper oxide minerals contain an abundance of PGEs as opposed to copper sulfide minerals. Sulfur mineralization is typical of hypogene (at depth, below crust) fluid flows that originate from magmas; however, the copper sulfide minerals analyzed did not contain a high amount of PGE elements, supporting the hypothesis that this enrichment was not the result of magmatic differentiation. The abundance of PGE-enrichment in more oxidized samples indicate that the PGE-enriched hydrothermal flows could have occurred as more of a secondary, supergene process (closer to the surface of the earth’s crust) that allowed for PGEs to remobilize to depth and enrich the samples via shear zones. Further pursuit for PGE ore deposits can be carried out by researching samples from areas with similar geologic history and characteristics.
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