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Chronology of multicultural site Sowinki in Greater Poland

Michalska D., Krzyszowski A.

Geochronometria

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2017

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Vol. 44, no. 1

30--39

EN

Sowinki is a village located 35 km south of Poznań, where archaeological research has revealed the remains of settlement from different archaeological periods, ranging from the Mesolithic (ca. six thousand years BC) to the Late Medieval period (ca. 15th century AD). This area, therefore, provides a record of the history of Greater Poland (Poznań) region, tracing back to about seven and a half thousand years ago. Samples of bones and wood were collected from different features, including mostly cellar pits, refuse pits and grave pits. Eight of the samples, all collected from grave pits, were selected for radiocarbon dating. The obtained 14C measurements have confirmed previous findings concerning different cultures registered in the studied area, and additionally, they have helped to clarify chronology of the early medieval cemetery. The presented results are the first isotopic measurements taken for the site of Sowinki. Previously, chronological frameworks of this site were determined on the basis of relative chronology, according to stratigraphy of sediments, examination of metal finds, pottery and flint objects. The deposition depth of the analysed charcoals did not exceed 100 cm below ground level. According to the analysis, all the samples date to the time of the early Piasts’ dynasty. The obtained data have allowed for defining two chronological phases of the early medieval cemetery. This is an important archaeological site both in terms of its spread and the long time of existence. In addition, it provides a valuable background for the study on the emergence of early medieval elites and the formation of the Polish “early feudal” state.

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Investigation of lime mortars and plasters from archaeological excavations in Hippos (Israel) using Electron Paramagnetic Resonance

Kabacińska Z., Krzyminiewski R., Michalska D., Dobosz B.

Geochronometria

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2014

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Vol. 41, no. 2

112--120

EN

This study presents the preliminary results of investigation of the lime mortars and plasters from archaeological excavations in Hippos (Israel), using Electron Paramagnetic Resonance (EPR) spectroscopy. The research was conducted in order to characterize the building material and its reaction to ionizing radiation. The ancient settlement Hippos, situated on the east shore of the Sea of Galilee, functioned from the 3rd cent. BC until it was destroyed by the earthquake in 749 AD. Lime mortars and plasters show carbonate and locally gypsum character of binder and different kind of aggregate. Samples were γ-irradiated and measured using X-band EPR spectrometer. Computer Resolution Enhancement Method was applied to the complex spectra. Some of the γ-induced EPR signals were attributed to CO 2 and CO 3 3- paramagnetic centres. Exponential growth of the dose response curve above 1 kGy and saturation for doses above 20 kGy was observed. For doses lower than 1 kGy the dose response curve has a linear character. The presence of γ-sensitive carbonate paramagnetic centres could indicate that, after further studies, well-chosen samples of mortars and plasters might be suitable for EPR dating, assuming the centres have been sufficiently bleached during the manufacturing process.

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Cretaceous aggregate and reservoir effect in dating of binding materials

Michalska D., Pazdur A., Czernik J., Szczepaniak M., Żurakowska M.

Geochronometria

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2013

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Vol. 40, no. 1

33-41

EN

Lime mortars may contain carbon from different origins. If the mortars are made of totally burnt lime, radiocarbon dating yields the true age of building construction. The presence of carbona-ceous aggregates gives the so-called dead carbon effect, which may generate older ages. Another source of carbon is charcoal present in mortars. An attempt has been made to apply the radiocarbon method to mortars of archaeologically estimated age from the Dead Sea region. Petrographical anal-yses of these samples show the carbonaceous character of the binder and large amounts of limestone aggregate. Determination of the mineral composition of the mortars and comparison with the geology of the surrounding, allows the provenance of the raw materials to be identified. They probably repre-sent the Cretaceous rocks of the Judea Group. Separate radiocarbon dates were made on bulk mortar samples, binder, charcoal fragments and sepa-rated fractions from mortars. In the case of binder-aggregate mixture the reservoir effect correction has been applied.