Reply to "A comment on Early Jurassic paleomagnetic study of lower Jurassic marine strata from the Neuquén Basin, Argentina: a new Jurassic apparent polar wander path for South America

IGLESIA LLANOS, M.P., RICCARDI, A.C. & SINGER, S.E.

EARTH AND PLANETARY SCIENCE LETTERS

Elsevier B.V.

Lugar: Amsterdam; Año: 2008 p. 316 - 319

0012-821X

The interpretation of significant apparent polar wander during the Early Jurassic was primarily established based on the premise that the obtained palaeopoles yield well-dated stratigraphical and palaeomagnetic ages. Because of the lack of available qualified well-dated poles from Africa of the critic Early Jurassic interval it was not possible to construct a well-defined APW path for that continent. Instead, we thought of working with the more reliable European palaeomagnetic poles. Significantly, they define practically the same path and in particular, the same Lower Jurassic cusp. Maximum velocities for a continent on the other hand, are not well established in the available literature. In fact there are no clear absolute limits for the rate of   plate motion. Yet, there are reports of minimum velocities as high as 24 cm y-1 for Laurentia and Gondwana or as mentioned, 26 cm y-1 for the Brasilian Craton. Taylor and Roperch state that localised rotations are of regular occurrence in the Andes, based on the palaeomagnetic work they performed in the fore-arc of the northern Chilean Central Andes that is located in a dissimilar tectonic setting and at least, 2000 km away from the Andes of the Neuquén back-arc basin. Despite this, palaeomagnetic studies in the literature have recorded large areas of the northern Central Andes that were NOT affected by significant block rotations. Moreover, it has been proposed that block rotation mechanisms in a fore-arc setting differ substantially from those of the back-arc domain. In addition, we want to remark that the palaeogeographical reconstruction we propose for South America is fully supported both by palaeomagnetic data from Eurasia which Taylor and Roperch seem to deliberately ignore, and independent palaeobiogeographical data from both hemispheres.