Paleointensity of the geomagnetic field from dated lavas of the Chaîne des Puys, France: 1. 7–12 Thousand years before present

Abstract

Paleointensities were determined by the Thellier method for six dated lava flows from the Chaîne des Puys (France), with ages from 7 to 12 ka (ka = kiloannum before present). The three younger flows overlap the archaeomagnetic period for Europe, and the older flows extend the record to more ancient times. Our results support the quasi‐sinusoidal variation of the geomagnetic field intensity since 10 ka for Europe, punctuated by a peak virtual dipole moment of about 11×1022 A m2 between 8 and 10 ka; the data from 10 to 12 ka show considerably lower virtual dipole moments between 4 and 5 × 1022 A m2, about 60% of the global average since 10 ka. When compared with available worldwide data, the maximum in the virtual dipole moment between 8 and 10 ka is supported by measurements from Japan and possibly Hawaii. Lower than average virtual dipole moments between 10 and 12 ka have also been observed in North America and Hawaii. The existing data suggest that from 8 to 10 ka the geomagnetic field supported a dipole moment up to 30% above and from 10 to 12 ka about 30% below the average value since 10 ka.