Comparison of different analysis methods applied in archaeological soil analysis with chemometric techniques in the interpretation of past human activity: A case study from the Yassıtepe Höyük in İzmir, Turkey

Abstract

In this study, human activities carried out in the past of the Yassıtepe Höyük, one of the most important Bronze Age settlements in Western Anatolia, were tried to be determined as a result of examining the data obtained from 108 anthropogenic soil samples (89 from the on-site; 19 from the off-site) taken from different points with chemometric modeling techniques. According to the moisture, pH, and total organic matter analyzes, the mean results were determined as 6.50 % ± 0.21, 8.44 ± 0.28, and 7.42 % ± 0.80 %, respectively. Some elements such as calcium, phosphorus, iron, sodium, potassium, magnesium, and sulfur are determined mean as 119548.15 ± 30680.23, 3497.41 ± 1494.37, 29414.82 ± 5221.90, 5148.15 ± 1072.29, 15962.96 ± 3391.98, 10737.96 ± 1917.15, and 1138.89 ± 420.47 mg L−1, respectively, by elemental analysis. The highest mean phosphorus ratio is reached in the M17 building (5105.00 ± 2886.98 mg L−1) and the IIB2-2 phase of this building had the highest mean phosphorus ratio (8432.50 ± 2199.75 mg L−1). According to the enrichment factor (EF) analysis, lead, arsenic, strontium, phosphorus, calcium, barium, potassium, beryllium, and sulfur elements were found to accumulate in the soil samples of the on-site. To determine which analysis techniques gave more meaningful results, 11 principal component analysis (PCA) models were created by using at least binary combinations of these analysis techniques, and the best PCA model was selected by evaluating their statistical values of the number of factors reached, the eigenvalue, and the number of samples outside of explained variance. The PCA model 6, which has the highest factor number of 7 and includes the results of total organic matter and elemental analysis, is chosen as the most successful model. In addition, it was seen that multivariate curve resolution-alternating least squares (MCR-ALS) data, which determined the distribution of the variables in the archaeological area, supported the EF and PCA data. According to the results, it is determined that the Yassıtepe Höyük and its surroundings have been exposed to intense human activity in the past and there has been an agricultural village life where shellfish have been consumed a lot due to high calcium rates with phosphorus. The large amount of waste belonging to various shellfish obtained from the archaeological studies carried out in the area confirms this result.