A two-dipole model is used to simulate the behaviour of the geomagnetic field during two successive polarity transitions (R→N followed by N→R) reported by VALET and LAJ (1981) from a 6Ma old marine clay sequence in western Crete. The model consists of an axial geocentric dipole and an offset minor dipole located at the northern core-mantle boundary. During the transitions the geocentric dipole decays exponentially through zero and then recovers its opposite polarity state. The axial offset dipole has two components: a time-varying and a standing one. In the middle part of the reversal process the standing component controls the transitional field and is responsible for the steep negative inclinations observed in both transitions.
The advantage of the two-dipole model compared to some other transition models is that it is capable of describing not only the inclination and intensity transitions but also the properties of the field during intervals of stable polarity, including the departure of inclinations from the axial geocentric dipole value, the symmetry of the older (R→N) reversal and the asymmetry of the younger (N→R) reversal. In a global perspective the model predicts that the shapes of intensity and inclination curves during the transitions depend on the observer's site latitude and that the onset and termination parts of these curves may differ. Because the model is axial it cannot produce the observed declination transitions. In spite of this the model produces VGP-latitude vs. stratigraphic height curves and field intensity vs. VGP-latitude curves consistent with results derived from Hoffman's flooding model.