NEW PALEOMAGNETIC RESULTS FROM ICELANDIC NEOGENE LAVAS

In this paper, some statistical properties of new collections of palaeomagnetic direction and intensity data are presented and compared with results from older collections. The new data come mostly from three composite surveys in the basalt lava pile of Iceland, totalling about 1000 lavas of ages 7-14 Myr. The palaeomagnetism of all these lavas converges on a reproducible long-term pattern in several important features of the Neogene field behaviour. Previous conclusions which are confirmed in this paper include: (1) the distribution of intermediate virtual geomagnetic poles (VGPs) is not confined to preferred longitude intervals; (2) normal- and reverse-polarity states of the geomagnetic field are essentially equivalent as regards the intensity of the field, mean field directions, and secular variation; (3) the virtual geomagnetic dipole moment falls off with decreasing VGP latitude, by a factor of 3.5-4 between polar and equatorial latitudes; (4) a significant reduction in the between-flow angular dispersion of VGPs may have occurred during the last 14 Myr; and (5) palaeomagnetic directions from Icelandic basalt lavas are stable and reliable.