RAPID IN-SITU RESIN IMPREGNATION OF UNCONSOLIDATED AEOLIAN SAND DUNES

Established methods for resin impregnation of sediments require long gel times (weeks to months) before samples can be transported. I’ve developed a method using surfboard resin to impregnate unconsolidated sand-gravel mixtures which allows them to be transported within 24 hours of the initial impregnation. This is an efficient and inexpensive technique which can be used to prepare thin sections of unconsolidated samples for micromorphologic studies. Micromorphology is typically applied to soils and other fine-grained deposits like glacial till, but I’ve developed this technique in order to apply micromorphology to gain a better understanding of the internal structure of harvester anthills in Southeastern Oregon.

The sampling site is located in a remote area without electricity, therefore it was not possible to impregnate the samples under vacuum, as would typically be done in a laboratory setting. I selected a surfboard resin that could be thinned to an extremely low viscosity, with a short-but-modifiable gel-time. To prevent the resin’s rapid dispersal in the unconsolidated sand and gravel of the anthills I carefully inserted a tin can with one end removed into the anthill. I then used a syringe to inject the resin through a small hole drilled in the closed end of the can, and left the sample to harden overnight. The samples were not completely cured, but they had hardened enough to be transported without any detectable damage to the anthill’s structure. A secondary impregnation conducted using a vacuum oven and the same resin mixture was sufficient to allow the samples to be sliced open for thin sectioning.

This technique has broad applications for study of bio-sedimentary structures, as the short gel time prevents the breakdown of organic matter which can occur with other resin impregnation techniques. My focus is on ants, but the macro-structure of a microbiological community could also be studied using this method.