Relative geomagnetic paleointensity across the Jaramillo subchron and the Matuyama/Brunhes boundary

Analysis of old paleomagnetic data and new mineral magnetic data from a sediment core from the central equatorial Pacific Ocean indicates that this core can be used for determination of relative geomagnetic paleointensity. These data indicate that during the Jaramillo subchron, there was a gradual decrease in paleointensity from the onset of the subchron to its termination. The data from the subchron also display high-amplitude, fine-scale features that may be coherent over the scale of an ocean basin. Furthermore, there was a rapid rise in paleointensity immediately after the termination of the Matuyama/Brunhes polarity transition. These observations support the hypothesis that an asymmetrical saw-tooth pattern in paleointensity may be a common characteristic of polarity transitions; however, a better understanding of the high-amplitude features is needed before definitive conclusions can be drawn about the overall behavior of the field. The coherence of fine-scale features across such large distances does not support the suggestion that the asymmetrical sawtooth pattern is an artifact of viscous remanent remagnetization.