A preliminary secular variation curve for archaeomagnetic dating in Austria

International audienceThe construction of a secular variation (SV) reference curve for a region for which little or no archaeomagnetic directions are available is presented here. A SV curve is illustrated for Austria, centred on Radstadt (47.38°N, 13.45°E) and based on data from sites in other countries less than 500 km away. The published data were selected on site characteristics of N = 3 and k = 50, and dated within 400 yr. This yielded 170 directions from which a SV curve was derived using Bayesian techniques. The obtained reference curve represents the past 2300 yr. New data, mainly from Austria, substantiate this curve and confirm the validity of the techniques employed which can, therefore, be applied for similar situations. Another test has been made using the German reference curve for dating the Austrian archaeological sites, here a systematic shift to older times in the order 30­110 yr occurs