Lessons from the Lagerstätte: An Ashfall Fossil Beds Retrospective and Update
University of Nebraska State Museum
Ashfall Fossil Beds in northeast Nebraska is a Miocene (Clarendonian) waterhole death assemblage containing fully articulated and associated skeletons of rhinoceroses, horses, camels, musk deer, birds and turtles preserved in death positions in volcanic ash. Subsequent to Ashfall’s discovery in 1972, some of the fossils were excavated and removed to the Museum collections (1977-1979), some partially excavated and reburied (1988-1990), and others exposed, prepared in-situ and left in place under the protection of the “Rhino Barn”, a structure providing limited control of environmental agents of deterioration (1991-2008). This thirty-year “experiment” has allowed us to observe differing modes and rates of deterioration and compare the efficacy of preservation strategies under various conditions. Collections made during the 1977-1979 field seasons, now housed in the University of Nebraska State Museum, present their own unique challenges. Approximately three thousand field jackets containing the remains of hundreds of individual skeletons were collected during this period. Each jacket was separately numbered and mapped and each contained perhaps only a part of a single articulated skeleton, or, more typically, parts of multiple skeletons of multiple taxa, associated elements and isolated elements, many of which were revealed only after preparation and thus not referenced in the field notes. Traditional collection databases such as Specify are incapable of tracking such complex associations of specimens or facilitating their full curation. Prior to a recent move and reorganization of these collections, we designed an inventory-based relational database capable of tracking all “objects” within the collection, regardless of their curatorial status, location or known associations. This database relates field notes, inventory observations, curator’s notes and catalogue records and is an essential tool in re-uniting individuals that had become dissociated during collection, preparation and years of research. In addition, newly designed, stable support systems were constructed for skulls and other heavy, fragile elements to improve storage and assure safe handling. Construction of a new, much larger “Rhino Barn” will begin in 2008, allowing excavation, in-situ preservation and research to continue for many years to come.
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