By Adrian Fenech, Graduate Diploma in Archaeology Student
The directed study I am working on involves reanalysing material excavated by Mick Morrison from Weipa in northern Queensland and uses sugar to aid the ‘floatation’ lab technique. I’m doing this because previous research projects on shell mound sites in northern Australia suggests that they contain very few faunal materials other than shellfish remains. The aim of this work is to find if the low recovery rate of faunal materials in samples is due to taphonomic or sampling technique biases. I am going to use chemical floatation to assist the sorting and faunal identification processes.
The chemical floatation process involves dry sieving the archaeological material and then immersing it in water that has been treated with some kind of chemical (Ross and Duffy 2000, p 33). This is designed to change the specific gravity of the water to separate materials that have different weights. For reasons of personal safety and economy, sugar will be used, hopefully the lab technicians, John and Chantal will not think that I am cooking in the lab.
A secondary process I am considering is defloccation which involves swirling archaeological materials around in a solution of water and some form of cleaning agent. I will be playing this by ear until I can see if the floatation cleans the material in any way.
Ross, A. and R. Duffy 2000, Fine mesh screening of midden material and the recovery of fish bone: the development of floatation and deflocculation techniques for an efficient and effective procedure. Geoarchaeology 15(1): pp. 21-41.
Vale, D. and R.H. Gargett 2002 Size matters: 3mm sieves do not increase richness in a fishbone assemblage from Arrawarr 1, an Aboriginal Australian shell midden on the mid-north coast of New South Wales, Australia. Journal of Archeological Science. vol. 29: pp. 57-63.