Nathan Irgang
Pronouns: He/Him/His
Research Mentor(s): Jennifer Bauer
Research Mentor School/College/Department: Museum of Paleontology / LSA
Program: UROP
Session: Session 1 (9:00am – 9:50am)
Authors: Jennifer Bauer, Nathan Irgang, Joseph Rathnaw
Abstract
Pyrite disease is a major problem that has plagued museums and collections facilities for over a century. Iron pyrite (FeS2) may be incorporated in fossils to a varying degree during the fossilization process. When these specimens are kept in a humid environment, oxidation of pyrite spontaneously occurs with oxygen and water in the air as represented in the following scheme: 4FeS2+13O2+2H2O 4FeSO4+2H2SO4+SO2 However, there is disagreement amongst chemists and paleontologists as to what form iron takes on in the products, with Fe(OH)3, FeOOH, and FeO having all been suggested. In an effort to seek better methods of treatment and long term preservation, a collection of over 200 invertebrate fossil specimens were analyzed and treated using a variety of methods to determine the most effective means for mitigating the effects of pyrite disease, with success being determined qualitatively based on improvement in the specimens visual appearance and a reduction of the oxidation byproducts, which take the form of a white powder on the surface of the specimen. Approaches included mechanical treatment, i.e. removal of byproduct with a brush, chemical treatment with compounds such as hydrogen peroxide, lithium aluminum hydride, and ethanolamine thioglycolate, or both chemical and mechanical treatments, in some cases. Upon subsequent analysis of these data, it was determined that hydrogen peroxide proved largely ineffective at reducing byproduct on specimens, instead being more effective at breaking up sediment attached to the specimens, resulting in misleading calculations for the percent weight lost following treatment. However, manually removing the byproduct proved helpful for long-term storage, as it can quickly remove much byproduct with little cost and effort. It appears that the most effective method was a combination of mechanical and chemical treatments, based on the combined benefits from both individual treatments to result in a decrease in both byproduct and sediment, while also maintaining a relatively low cost and effort threshold. These data provide insight into how museum professionals can efficiently treat fossil and rock specimens that are prone to pyrite oxidation. With this information, long and short-term treatment plans can be established for material to insure preservation of the material in perpetuity.
