Paleointensity determination from São Miguel (Azores Archipelago) over the last 3 ka

In the Atlantic Ocean paleointensity data are scarce. New paleointensity data from 24 paleomagnetic sites from 14 lava flows emplaced during the last 3,000 years at Sao Miguel (Azores Islands, Portugal) are presented in this study. Ten lava flows are radiocarbon dated (Moore 1990, 1991; Moore and Rubin, 1991), whereas three flows were archeomagnetic dated by Di Chiara et al. (2012) and one site was dated using stratigraphic relations. All the samples, previously investigated to recover paleodirections (Di Chiara et al., 2012), were carefully preselected to fulfill the assumption of the method and then subjected to IZZI experiments. Importantly, the new data are internally consistent, and agree with Moroccan, and European datasets, as well as with the Cals3k.4 predictions (Korte et al. 2011), varying from 63.29 ZAm2 and 168.8 ZAm2. Data show three minima around 1563 AD, 1050 AD, and 400 AD, and three maxima around 1070 and 1300 AD, 700-800 AD and 593 BC. The peak of intensity around 600 BC is well supported by two sites from the same flow (Furna), and is comparable to the 'spike' of intensity founded in West Levant records, as well as in Western Europe. The Latitudinal gradient from lower to higher Latitudes observed by Mitra et al.(2013) between 100 to 1000 AD m is confirmed as well as the predominance of the axialdipole component between 0 to 100 AD Paleointensity results from sites and flows from Sao Miguel Declination and Inclination are from Di Chiara et al (2012). Mean intensity results are reported by flow (mT and VADM converted), after IZZI experiments and processed using the "pmagpy-2.173" by L. Tauxe.