Invertebrate fossil preparation

The delicate nature of the specimens at Florissant Fossil Beds National Monument, Colorado requires a constant monitoring of the collections. The overall stability of the fossils is greatly impacted by the abrupt change in humidity that may occur after the paper shale has been excavated, as well as the varying levels of humidity in the collections and display areas. Creating methods to effectively “acclimate” the shale’s transition from the ground to the lab, and finding and maintaining the ideal humidity range for our collections room is integral to the collections management at Florissant Fossil Beds. For these experiments, a controlled environment chamber was used, employing both humidification and dehumidification systems. The humidity is systematically lowered to slowly dehydrate
damp shale and safely lower it to the ambient relative humidity (RH) in the lab and collections areas. Tests have also been run to monitor damages the shale undergoes when it reaches a certain level of humidity. Below 25% RH, deformation occurs in the form of flaking and delamination. Initial data suggest that the ideal range to keep the collections area is between 30-35%. These tests will ultimately become the basis for a protocol that will outline how the paper shale will be handled once excavated, and how the collections area should be maintained.