Archaeomagnetic directional studies of large fired structures in Britain
Archaeomagnetic directional dating of several Scottish sites has been undertaken by extensive sampling of large, physically stable vitrified exposures. Isothermal remanences and the deinagnetisation patterns isolated using alternating magnetic fields and thermal methods, show that vitrification occurred under limited oxidation at temperatures >600Â°C and - that the vitrification was physically stable below 600Â°C at all but one of the sampled structures. Remanence directions were isolated by demagnetisation techniques and show that these sampled forts and duns collectively span a period from the late 3rd century B.C. to 5th century A.D. Calibration of mean magnetic directions shows general consistency with 14C dating but not with thermoluminescence dates. An archaeomaqnetic curve of ~best fit~ incorporating all dating methods largely confirms the previous Iron Age secular variation curve. Field observations, systematic sampling and magnetic measurement of features of various archaeological ages, as well as an experimental kiln, has shown that there are both random and systematic directional deviations which do not precisely correlate with other magnetic properties. These deviations are thought to be due to
Gentles, Dougall Stanley
Archaeology
Archaeomagnetic directional studies of large fired structures in Britain. Archaeomagnetic directional dating of several Scottish sites has been undertaken by extensive sampling of large, physically stable vitrified exposures. Isothermal remanences and the deinagnetisation patterns isolated using alternating magnetic fields and thermal methods, show that vitrification occurred under limited oxidation at temperatures >600Â°C and - that the vitrification was physically stable below 600Â°C at all but one of the sampled structures. Remanence directions were isolated by demagnetisation techniques and show that these sampled forts and duns collectively span a period from the late 3rd century B.C. to 5th century A.D. Calibration of mean magnetic directions shows general consistency with 14C dating but not with thermoluminescence dates. An archaeomaqnetic curve of ~best fit~ incorporating all dating methods largely confirms the previous Iron Age secular variation curve. Field observations, systematic sampling and magnetic measurement of features of various archaeological ages, as well as an experimental kiln, has shown that there are both random and systematic directional deviations which do not precisely correlate with other magnetic properties. These deviations are thought to be due to
archaeomagnetic directional study large fire structure britain archaeomagnetic directional date several scottish site undertake extensive sample large physically stable exposure pattern isolate use alternate magnetic field thermal method show occur limited oxidation temperature adegc physically stable sampled structure direction isolate technique show sample fort collectively span_period century calibration mean magnetic direction show general consistency date thermoluminescence date curve best fit incorporate date_method largely confirm previous iron_age secular variation curve field_observation systematic sample magnetic measurement feature various archaeological age well experimental kiln show random systematic directional deviation precisely correlate magnetic property deviation think due