|
ИСТИНА |
Войти в систему Регистрация |
Интеллектуальная Система Тематического Исследования НАукометрических данных |
||
High-coercivity magnetic minerals in archaeological ceramics: newinsights from remanence acquisition and demagnetizationmeasurements at elevated temperaturesтезисы доклада
- Авторы: Andrei Kosterov, Mary Kovacheva, Maria Kostadinova-Avramova, Pavel Minaev, Natalia Salnaia, Leonid Surovitckii, Svetlana Yanson, Elena Sergienko
- Сборник: European Geosciences Union General Assembly 2020
- Тезисы
- Год издания: 2020
- Издательство: Copernicus GmbH on behalf of the European Geosciences Union
- Местоположение издательства: Germany
- DOI: 10.5194/egusphere-egu2020-10130
- Аннотация: The thorough understanding of magnetic mineralogy is a prerequisite of any successfulpalaeomagnetic, and in particular, archaeomagnetic study. Magnetic minerals in archaeologicalceramics and baked clay may be inherited from the parent material, or, more frequently, formedduring the firing process. The resulting magnetic mineralogy may be complex, includingferrimagnetic phases not commonly encountered in rocks. Towards this end, we carried out adetailed rock magnetic study on a representative collection of archaeological ceramics (baked clayfrom combustion structures and bricks) from Bulgaria and Russia. Experiments includedmeasurement of isothermal remanence acquisition and demagnetization as a function oftemperature between 20°C and >600°C, and a variant of Lowrie 3-axis IRM test withmeasurements performed at elevated temperatures. For selected samples, low-temperaturemeasurements of saturation remanence and initial magnetic susceptibility between 1.8 K and 300K have been carried out.All studied samples contain a magnetically soft mineral identified as maghemite probablysubstituted by Al and/or Ti. Stoichiometric magnetite has never been observed, as evidenced bythe absence of the Verwey phase transition. In addition, one or two magnetically hard mineralphases have been detected, differing sharply in their respective unblocking temperatures. One ofthese unblocking between 540°C and 620°C is believed to be substituted hematite. Another phaseunblocks at much lower temperatures, between 140°C and 240°C, and its magnetic propertiescorrespond to an enigmatic high coercivity, stable?, low unblocking temperature (HCSLT) phase ofMcIntosh et al. [McIntosh, G., M. Kovacheva, G. Catanzariti, M. L. Osete, and L. Casas (2007),Geophys. Res. Lett., 34, L21302, doi: 10.1029/2007GL031168]. In a few samples high- and low-unblocking temperature magnetically hard phases appear to coexist, in the others the HCSLTphase is the only magnetically hard mineral present. We finally compare the samples performancein archaeointensity experiments with their respective magnetic mineralogy (PDF) High-coercivity magnetic minerals in archaeological ceramics: new insights from remanence acquisition and demagnetization measurements at elevated temperatures. Available from: https://www.researchgate.net/publication/340687026_High-coercivity_magnetic_minerals_in_archaeological_ceramics_new_insights_from_remanence_acquisition_and_demagnetization_measurements_at_elevated_temperatures [accessed Aug 15 2020].
- Добавил в систему: Сальная Наталья Викторовна