An updated archeomagnetic directional variation curve for France over the past two millennia, following 25 years of additional data acquisition
Maxime Le Goff|Yves Gallet|Nicolas Warmé|Agnès Genevey
Nearly 40 years ago, Emile Thellier published an article summarizing the archeomagnetic data he had obtained during his career, which allowed him to recover main features of directional variations geomagnetic field in France for last two millennia. This database went on be significantly completed 25 ago by Ileana Bucur, who taken over Thellier's work archeomagnetism; this forms current basis our knowledge evolution France. Since then, studies have been continued at historical laboratory Saint Maur. presents past same laboratory. A total 528 new are presented, which, together with 170 results French territory previously listed Bucur (1994), constitute (698 all). All but these were using experimental protocol developed E. based analysis large samples and a magnetic viscosity test that has proved its reliability numerous occasions. The directions from entire precisely defined, 95% α95 values being less than 1.9°, ~ 50% 0.8°. selection 286 dating uncertainties ≤50 us compute reference variation curve since first century BC sliding windows, variable durations shifts adapted time distribution available data, bivariate extension Fisher statistics. shows ample smooth variations, fairly similar those determined much smaller database. resulting secular is particularly well suited use dating.
Physics of the Earth and Planetary Interiors|HAL (Le Centre pour la Communication Scientifique Directe)|HAL (Le Centre pour la Communication Scientifique Directe)|HAL (Le Centre pour la Communication Scientifique Directe)|HAL (Le Centre pour la Communication Scientifique Directe)