Parks Stewardship Forum

Florissant Fossil Beds National Monument (FLFO) was established to protect the rare abundance and diversity of fossil resources preserved in the Florissant Formation. The majority of fossils are plants and insects preserved in laminated shale, which is prone to conservation issues. These issues result from the inherent thinness of individual laminae (≥0.1 mm) and high clay content, and, during collection, sharp fluctuations in relative humidity (RH) and moisture content. The purpose of this paper is to describe historical and current stabilization methods, and report on two current research efforts at separate institutions to mediate these issues using controlled drying techniques and selection of appropriate adhesives and consolidants following best practices in fossil preparation. Response of shale units to humidity is being investigated at the Western Archeological and Conservation Center facility in Tucson, Arizona, along with the viability of consolidation with tetraethyl orthosilicate (TEOS). This method controls humidity and moisture during drying procedures in order to prevent cracking, flaking, and delamination of the shale matrix for both untreated and treated samples. Results indicate that consolidation with TEOS can prevent damage from occurring during the drying process if the samples are maintained in a hydrated state while the TEOS forms a sol-gel. Without treatment, a slow and moderate drying cycle longer than 14 days without acute drops in (RH) is necessary to prevent damage. To test appropriate adhesives and consolidants that assist in preventing and repairing damage to fossil specimens, analysis is being performed at the National Center for Preservation Technology and Training in Natchitoches, Louisiana. The properties of two ethyl-cyanoacrylates, a medical-grade butyl-octyl cyanoacrylate, and Butvars B-98 and B-76 in 95% ethanol were compared against each other after treated paper shalesamples were stressed under accelerated aging conditions in a weatherometer and analyzed using Fourier Transform Infrared Spectroscopy (FTIR). Results indicate that the paper shale samples treated with a consolidant using the two Butvar resins remain the most stable over time under extreme conditions. Updated methods of drying shale after extraction and using appropriate adhesives and consolidants will ensure conservation of the paleontological specimens at FLFO for ongoing research and public understanding into the future.