TY - THES

T1 - Palaeointensity of the geomagnetic field recorded in two multilevel archaeological sites in Austria

AU - Thallner, Daniele

N1 - embargoed until null

PY - 2016

Y1 - 2016

N2 - To understand the origin as well as the history of Earth's magnetic field, it is necessary to gain information about the field for longer periods of time. This information is stored in magnetic minerals in rocks in the form of a remanent magnetisation, that was gained during the cooling of the rock from a high temperature and can be determined with palaeomagnetic methods. With the age of the last cooling of the rock, which can be determined by geochronological dating methods, models of the temporal changes of Earth's magnetic field can be computed. These model curves can then be used to verify the results of the geochronological and archaeological datings. For this thesis, samples from two archaeological sites in Austria have been worked on. The first site in Semlach/Eisner was a Roman iron production facility in Carinthia (Cech, 2008). Intensity measurements were conducted on fragments of three furnaces. The second site was the early medieval Valley settlement in Thunau am Kamp (Obenaus, 2015). Here, three oven features were sampled and the direction and intensity of their magnetisation was measured. Furthermore, the palaeointensities of three other ovens as well as ceramic shards associated with four other ovens have been determined. The intensities were measured with both domain state corrected multispecimen protocol experiments (Fabian and Leonhardt, 2010) and Thellier experiments in the version of Coe (1967). After a discussion to show that the measured values represent the ancient magnetic field, the measured directions and intensities were used together with already published data from Semlach and Thunau (Schnepp, et al. 2015; Schnepp, 2016; Schnepp, (accepted) 2017) to date the features. With the exception of one feature of Thunau, where it was not possible to conduct successful intensity measurements, the archaeological ages of all features could be verified. In this thesis, three new directions and 11 new intensities have been found that can be used to compute and improve reference curves of the ancient magnetic field.

AB - To understand the origin as well as the history of Earth's magnetic field, it is necessary to gain information about the field for longer periods of time. This information is stored in magnetic minerals in rocks in the form of a remanent magnetisation, that was gained during the cooling of the rock from a high temperature and can be determined with palaeomagnetic methods. With the age of the last cooling of the rock, which can be determined by geochronological dating methods, models of the temporal changes of Earth's magnetic field can be computed. These model curves can then be used to verify the results of the geochronological and archaeological datings. For this thesis, samples from two archaeological sites in Austria have been worked on. The first site in Semlach/Eisner was a Roman iron production facility in Carinthia (Cech, 2008). Intensity measurements were conducted on fragments of three furnaces. The second site was the early medieval Valley settlement in Thunau am Kamp (Obenaus, 2015). Here, three oven features were sampled and the direction and intensity of their magnetisation was measured. Furthermore, the palaeointensities of three other ovens as well as ceramic shards associated with four other ovens have been determined. The intensities were measured with both domain state corrected multispecimen protocol experiments (Fabian and Leonhardt, 2010) and Thellier experiments in the version of Coe (1967). After a discussion to show that the measured values represent the ancient magnetic field, the measured directions and intensities were used together with already published data from Semlach and Thunau (Schnepp, et al. 2015; Schnepp, 2016; Schnepp, (accepted) 2017) to date the features. With the exception of one feature of Thunau, where it was not possible to conduct successful intensity measurements, the archaeological ages of all features could be verified. In this thesis, three new directions and 11 new intensities have been found that can be used to compute and improve reference curves of the ancient magnetic field.

KW - Earth's Magnetic Field

KW - Secular Variation

KW - Archaeomagnetism

KW - Palaeointensity

KW - Dating

KW - Thunau am Kamp

KW - Semlach/Eisner

KW - Austria

KW - Erdmagnetfeld

KW - Säkularvariation

KW - Archäomagnetismus

KW - Paläointensität

KW - Datierung

KW - Thunau am Kamp

KW - Semlach/Eisner

KW - Österreich

M3 - Master's Thesis

ER -