Reply by the authors to ‘Comments on “Palaeomagnetism of the Lisbon Volcanics”’ by R. Van der Voo

Reply. Although we re-state our observation that the lavas are undisturbed (since there is no definite evidence of significant faulting or folding) we acknowledge the fact that the Lisbon Volcanics are not flat, if ' flat ' is understood to mean 0" dip. We have used the term ' flat-lying ' to be indicative of a f 5" dip which is not creating a geological precedent. We in fact detected a 5" southeastward dip on the enclosing sediments exposed in roadcuts of the area north of Lisbon, and corrected for this in the presentation of our data. In our opinion no other local tectonic dips close to the sampled bodies were definitely proven to exist, except perhaps near lava number 11 (Fig. 2 of our paper) where a partially columnar body dipped 45" westwards: this was not sampled at this locality because of uncertainties about the origin of its outcrop configuration. We would point out that Van der Voo is being selective in citing the area's Jurassic to Miocene (west to east) outcrop sequence as proof of uniform eastward regional dip, since he could as well describe the Miocene to Cretaceous (west to east) outcrop sequence near Lisbon, or the Miocene to Jurassic (west to east) sequence west of Alverca. In any case, even if our mean palaeomagnetic direction for the Lisbon volcanics is further rotated by an amount corresponding to an additional hypothetical 10" eastward dip of the lavas, the palaeomagnetic declination is still west of geographic north, west of the stable European Eocene palaeomagnetic pole position, and therefore not in conflict with post-Eocene rotation of the Iberian peninsula. Van der Voo essentially echoes this possibility by stating that such rotation may have been ' nearly completed ' by Eocene times.