THE DESIGN AND CONSTRUCTION OF A LOW COST SETTLING COLUMN FOR TAPHONOMIC RESEARCH

In order to understand the taphonomic histories of fossils found in fluvial sediments, it is essential to understand their transport potential. In order to investigate the transport properties of both small (rodent) and large (deer) sized bones an inexpensive large settling column had to be designed and built. Presented here is a description of the materials necessary and the method of fabrication of an 18x18x72 inch settling column, designed for taphonomic studies of modern animal bones.

The column is fabricated from five sheets of plexiglass epoxied together; four sheets forming the sides, and one the base. Each corner is further reinforced by the addition of metal corner brackets along the entire height and base of the column. All seems on the inside and outside of the column were calked and allowed to dry. With the addition of water the glass bowed outward, which had to be solved by applying pressure to the exterior surface of the sides. This was accomplished by metal plumbing hanging strip wrapped around the column and tightened using nuts, bolts, and washers. To further tighten the metal straps, bolts were screwed in to the metal strapping to push against a metal plate on the face of the plexiglass. This design allows variable pressure to be generated along each side of the column at different places.

To remove settled material from the column a square ¼ inch wire mesh basket was fabricated with a ¾ inch lip, then lined from below with 1mm fiberglass window screen. The two meshes were sewed together with fishing line to prevent scraping on the sides of the column. This apparatus was then weighed down to encourage faster sinking. To remove the basket from the column, fishing line was secured at each corner and the bundle of all four strands was threaded through a metal loop to prevent tangling. A cardboard top was also manufactured to prevent insects and other biological material from entering the column. Commercial chlorine tablets were used to further prevent biological growth.