Paleomagnetic secular variation at the Azores during the last 3 ka

摘要: [1] We report on 33 new paleomagnetic directions obtained from 16 lava flows emplaced in the last 3 ka Sao Miguel, largest island of Azores. The data provide 27 well-dated historical or 14C dated which, together with 6 previously gathered same by Johnson et al. (1998), yield first directional record Atlantic Ocean. Within-flow are consistent, suggesting that inclination swings 60° to 25° and declination changes between −10° 20° reflect variations geomagnetic field over ka. To a approximation, is consistent predictions CALS3k.4 gufm1 global models. Conversely, values lower than model at two different ages: 1) four sites 1652 AD flow I = 48° instead 63° predicted gufm1; 2) several nicely mimic minimum 800–1400 AD, but ∼10° predictions. By interpolating cubic spline fit / versus age data, we tentatively infer evolution Azores 1000 BC 1600 AD. curve shows three tracks virtual overlap during 1000–800 BC, 800–500 400–700 time spans.