Soil Chemistry

The Chemical Analyses of Floor Sediments

Diverse domestic activities such as craft production (assorted debris and residues), cooking (wood ash, salts and minerals), food preparation (inorganic and organic midden remains), human waste and animal husbandry (high concentration of phosphate and other elements) can be identified because they leave chemical signatures on earthen floors. Initially phosphate was considered the only marker of anthropogenic activity and for decades it was successfully used to identify human activity. However, in recent years the use of an ICP-OES (Inductively Coupled Plasma Optical Emission Spectroscopy also called ICP-AES Inductively Coupled Plasma Atomic Emission Spectroscopy), has allowed for the expansion of the elemental suite. The instrument can quantitatively analyze a dozen elements simultaneously to detect anthropogenic activities. Analyses conducted with ICP-OES are often far more revealing than the results obtained by extractable phosphates. This instrument is available at Koç University, in the laboratory of Dr. Funda Acar Yağcı.

Sampling Process (Barcın Höyük)

Sampling Process (Tell Atchana/Alalakh)

Procedure: To conduct the analyses, first sediment samples are collected from living floors of archaeological settlements on a grid. Samples are brought back to the lab, weighed and placed into vials. A solution of dilute hydrochloric acid is thereafter added to each vial. After approximately half a minute of intense agitation, the vials are placed aside for 2 weeks at room temperature. Following this 14 day period, after the extract is filtered to remove the solution of any solids, the filtrate can be analyzed for a series of elements including Aluminum, Al; Barium, Ba; Calcium, Ca; Iron, Fe; Magnesium, Mg; Manganese, Mn; Sodium, Na; Phosphorus, P; Strontium, Sr; Titanium, Ti; and Zinc, Zn. Elemental concentrations recorded in parts per million (ppm) and must thereafter be log-transformed for statistical analyses and plotted on the settlement plan using a GIS program. In order to account for any variability caused by the parent material, activity residues must always interpreted with respect to geological control samples.

 Contact: Dr. Rana Özbal