By Adrian Fenech, Graduate Diploma in Archaeology Student
I have started the floatation procedure that I described in my earlier post and it is proceeding reasonably quickly. I am still thinking about the defloccation procedure but I am unsure if I will have enough time to accommodate it.
Despite the mess of sugar water I am making in the archaeology labs, the floatation is going well because it has managed to float quite a few materials that will be picked out in the sorting stage. So far, the dominant floated materials have been charcoal and vegetation, the former would have been difficult to locate in sorting. This is because of the many other dark-coloured materials in the samples. The photos below show the resulting fractions produced by the floatation work.
Light fraction: material which floated
Heavy fraction: material that sank
The photos show the contrast in materials that the floatation produced. The light fraction consists primarily of charcoal with some vegetation and a few shells. The heavy fraction is dominated by shell with a considerable amount of stones and some faunal material (from a glance). I’ve only just begun the slow process of sorting through the heavy fractions; hopefully I’ll find some non-molluscan fauna!
I am considering the defloccation procedure because the sugar water is often black after its second floatation. After the materials have been rinsed off, they are still encrusted with a considerable amount of sediment. A test will have to be performed; two samples of materials, one with defloccation performed and one without will be sorted and the ease of sorting will be compared. This will be subjective, though because it will be difficult to get two samples that are equal in quantities of material types.
