Friday, June 4, 2010
NECROPOLIS, SARCOPHAGUS, PINUS
While Dinosaur National Monument as a whole contains a diverse collection of cultural and natural resources, it is the Carnegie Quarry that makes it unique and the resource for which the Monument was originally established. So protecting the quarry face is a top concern during the QVC work. Nothing like this has ever been done before at a fossil quarry site.
The central problem was how to prevent an object or piece of equipment from hitting the quarry face and damaging the bones. One common early suggested solution was to cover the face in an expanding, hardening foam. The idea was to first put down a layer of plastic sheeting, spray the foam over it, and let the foam harden into a shell. Seems simple enough but closer evaluation reveals some serious problems.
First, the 70 degree slope of the quarry face would present problems getting a layer of foam of even thickness and complete coverage. Any object hitting the foam would transmit some energy through the foam. For smaller objects that might not be an issue, but large tools or pieces of equipment might break fragile bones under the foam.
Furthermore, the 1500 bones on the quarry face are exposed in bas-relief, with undercuts around and under transverse processes, ribs, pneumatic features, neural spines, etc. Under this approach to protection, when the Quarry Visitor Center project was completed, we would essentially have to re-excavate the entire quarry face, only this time preparing away hardened foam rather than sandstone. The particulates generated through this re-excavation would pose a health threat to those doing the work and would have to be completely captured by the air-filtration system in the refurbished building.
Ultimately the decision was made to enclose the entire face in a rigid structure that is held well away of the quarry face. Work planned for the Quarry Visitor Center includes redoing the ceiling. The company that is erecting the scaffolding for that part of the project came up with idea combining the scaffolding structure itself with plywood to form a rigid structure that would thus serve both as a work platform and a wooden sarcophagus. The scaffolding is 50 feet high and 150 feet in length. It will take several weeks, and plenty of plywood, to get this part of the project done. We’ll follow the process of this work over several posts, but here are some photos of the initial stages of the erection of the scaffolding at the west end of the building and the first sheets of plywood being hauled up and anchored in place.
(1) Russell, D.A. 1980. Reflections of the dinosaurian world. in: Jacobs, L.L. (ed.) Aspects of Vertebrate History, Essays in Honor of Edwin Harris Colbert. Museum of Northern Arizona Press: pp. 257-268.
Photo credits: Dinosaur National Monument