Dating of ancient kilns: A combined archaeomagnetic and thermoluminescence analysis applied to a brick workshop at Kato Achaia, Greece

Abstract

We present here the results of a detailed archaeomagnetic and thermoluminescence investigation performed on bricks from two ancient kilns excavated at Kato Achaia, Greece. Magnetic mineralogy measurements have been carried out to determine the main magnetic carrier of the samples. The directions of the characteristic remanent magnetization of each structure have been obtained from standard thermal demagnetisation procedures and the absolute archaeointensity has been determined with the Thellier modified by Coe method, accompanied by regular partial thermoremanent magnetization (pTRM) checks. The full geomagnetic field vector was used for the archaeomagnetic dating of the two kilns, after comparison with the reference secular variation curves calculated directly at the site of Kato Achaia. Independent dating has also been obtained from thermoluminescence (TL) analysis on four brick samples from each kiln. The dating results obtained from the two methods have been compared and the last firing of each kiln has been estimated from the combination of the two techniques. Using the independent date offered by TL dating, the new archaeomagnetic data have been compared with other data from the same time period and they can further be used as reference points to enrich our knowledge about the past secular variation of the Earth's magnetic field in Greece.

Archaeomagnetic study and thermoluminescence dating of Protobyzantine kilns (Megali Kypsa, North Greece)

“…For the present study the procedure previously applied by Tema et al (2013aTema et al ( , 2014 was also adopted; however in the framework of the present study the dose applied was similar to the equivalent dose of each kiln while the storage time was three months. Eventually, negligible anomalous fading was detected, less than 1%, a value, which does not require any correction.…”

Refining Holocene geochronologies using palaeomagnetic records

“…(2013) gave two potential time intervals and hence larger uncertainty than the TL dating. A more conclusive application of the method was using full vector magnetic results from two kilns in Greece (Tema et al, 2015 -Chakrouni et al, 2013;Casas et al, 2018) or burnt cave sediments from the Bronze age in Spain (Carrancho et al, 2017).…”

The dawn of archeomagnetic dating

“…Recurrence is more frequent for intensities, such as between the 6th and 9th-10th centuries or between the 14th and 15th centuries [Figure 7b; Genevey et al, 2016Genevey et al, , 2021. It obviously follows that archeomagnetic dating based on both direction and intensity is more likely to provide a unique dating determination, especially if the reference time interval is only one or two millennia [Tema et al, 2015]. This combined approach, capable of resolving the "train-induced ambiguity" mentioned by Brunhes, is now possible in Europe, thanks to recent advances made in our knowledge of geomagnetic secular variation over the past few millennia.…”