Geomagnetic field behavior before and after the Kauai reverse-normal polarity transition

New paleomagnetic results from 4 m.y. old lava flows from Kauai, Hawaii, su ggest that strong poloidal field is associated with an unusual state of the geodynamo that follows attempts at polarity reversal (successful or not). The new data comprise 50 paleomagnetic sites from superposed lava flows occ urring just below and above the Kauai reverse-normal polarity transition. A composite record of 45 distinct field determinations was constructed by co mbining sites that record similar ancient field and correlating them to pre viously published results from Kauai. Of the 45 data, 25 include paleointen sity estimates derived from double-heating experiments. A comparison of the composite record from Kauai with two similar data sets from volcanic seque nces shows that field variability tin direction, intensity, or both) can ch ange substantially across a polarity transition. These changes, however, do not appear to be systematic in sign or magnitude. The only feature common to all three records is high field strength in the posttransitional interva l, interpreted here as a transient phenomenon associated with the reversal process.