Midden sample floatation process going swimmingly

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.

One response to “Midden sample floatation process going swimmingly

  1. HI Adrian, it is fantastic that you are using this flotation method – are you using the flotation tank at the SA Museum? I gave the archaeobotany lectures and flotation pracs until about two years ago and encouraged students to use flotation in preference to dry sieving when looking at hearths and middens – but you are only the second person at FU that I know of using this method. I would love to catch up and see your work. regards, Pam Smith

    Dr Pamela Smith, PhD AACAI
    Senior Research Fellow
    Department of Archaeology
    Flinders University

    e: Pamela.Smith@flinders.edu.au
    p/f: 0882788172 or 0428315266