Joint 118th Annual Cordilleran/72nd Annual Rocky Mountain Section Meeting - 2022

Paper No. 34-3
Presentation Time: 8:40 AM


CALVO-RATHERT, Manuel1, GARCÍA-REDONDO, Natalia1, CARRANCHO, Angel2, LICHELI, Vachtang3, GOGICHAISHVILI, Avto4, DEKKERS, Mark5 and BRADAK-HAYASHI, Balazs6, (1)Departamento de Fisica, Universidad de Burgos, Av. de Cantabria, s/n, Burgos, 09006, Spain, (2)Departamento de Historia, Geografia y Comunicacion, Universidad de Burgos, Plaza Misael Bañuelos, s/n, Burgos, 09001, Spain, (3)Institute of Archaeology, Tbilisi State University, Tbilisi, Georgia, (4)Laboratorio Interinstitucional de Magnetismo Natural, Universidad Nacional Autonoma de Mexico, Morelia, Mexico, (5)Department of Earth Sciences, Paleomagnetic Laboratory Fort Hoofddijk, Utrecht University, Utrecht, Netherlands, (6)Kobe University, Kobe, Japan

In this study we present archeomagnetic and archaeointensity results obtained on burnt archaeological material from the Grakliani archaeological site in the Republic of Georgia. Based on stratigraphic and archaeological information, all studied samples have been chronologically framed between the 12th and 1st centuries BC. The aim of this work was to obtain more information about the variation of the Earth's magnetic field in the Caucasus in this age range and, where possible, to contribute to the dating of the sites.

Paleomagnetic experiments including thermal and alternating field demagnetisation were carried out on nine combustion structures. Archaeointensity experiments were performed on six combustion structures and eight ceramic fragments with two different Thellier-type methods, the Coe and IZZI variants. Additional experiments to correct the effect of anisotropy of thermoremanence (ATRM) were also carried out. Previously, rock magnetism experiments including IRM acquisition curves, hysteresis loops and backfield curves, as well as thermomagnetic curves had been carried out on all studied samples to obtain information about the carriers of remanence and to find out if they were suitable for archaeointensity determinations.

Reliable paleomagnetic results could be obtained in all nine studied combustion structures. In addition, successful archaeointensity determinations were attained in six combustion structures and seven ceramic fragments. ATRM corrected archaeointensity results range between 64.8 and 94.3 µT. A preliminary archaeomagnetic dating was attempted in six combustion structures, but attainment of unambiguous dates is hindered by the lack of reliable archaeomagnetic data in the Caucasus region for the studied age range (XII BC - I BC). Currently, new 14C age determinations are being carried out on some of the studied materials to provide new high-quality archaeomagnetic data to the secular variation curve of the Caucasus.