ARCHAEOMAGNETIC DATING OF 7 ARCHAEOLOGICAL FIREPLACES IN THE NETHERLANDS

The palaeomagnetic directions of seven Dutch fireplaces are compared w ith the archaeological age estimates which range from the first to the 17(th) century AD. A comparison with the British master curve of secu lar variation for archaeomagnetic dating results in a refinement of th e archaeological age estimates in two cases, while four other archaeol ogical age estimates can be confirmed. For one fireplace only one samp le is reliable, resulting in a very poorly defined archaeomagnetic age of 2 to 3 centuries younger than the expected age (i.e. late Middle A ges). On the other hand,; accepting the archaeological age estimates, the palaeomagnetic directions can contribute to the database that is u sed to construct the British secular-variation master curve. We applie d the classification grades proposed by Tarling & Dobson (1995) which range from unreliable (grade 1) to reliable (grade 5). Three fireplace s have grades 5, one has grade 4, one grade 3, one grade 1 and for one case no grade was assigned.