Apparent polar wander of the mean-lithosphere reference frame

Abstract

Apparent polar wander in the mean-lithosphere (= no-net-rotation = no-net-torque uniform drag) reference frame is compared with apparent polar wander in the hotspot reference frame over the past 100 Myr. Palaeomagnetic poles and plate rotations previously used to determine an apparent polar wander path for the hotspot reference frame are here used to determine an apparent polar wander path in the mean-lithosphere reference frame. We find that the two paths are similar, especially for Late Cretaceous time, when a 10"-20" shift of the pole occurred. To first-order the hotspots and lithosphere (as a whole) moved in unison relative to the palaeomagnetic axis during Late Cretaceous time. A non-dipole field explanation for the apparent shift can probably be excluded. However, either motion of the time-averaged geomagnetic axis relative to the spin axis or polar wandering could have caused this shift, the latter being the more likely explanation.

New paleomagnetic pole for the Upper Jurassic Chon Aike Formation of southern Argentina (South America): Testing the tectonic stability of Patagonia with respect to South America, and implications to Middle Jurassic-Early Cretaceous true polar wander

“…This can be achieved by comparison of apparent polar wander (APW) paths which are a temporal sequence of paleomagnetic poles, obtained from a variety of rock types. APW paths record the tectonic movements of lithospheric plates and, if active, true polar wander (TPW) which is the displacement of an entire, rigid Earth with respect to its spin axis (Goldreich and Toomre, 1969;Gordon and Livermore, 1987). Paleomagnetic poles are also very useful to test tectonic rotations (around a vertical axis) of lithospheric blocks due to the activity of fault systems with lateral displacements.…”

Paleomagnetism of the Patagonian Plateau Basalts, southern Chile and Argentina

“…Determination of APW paths has been a major goal of paleomagnetic research, and numerous techniques for determination, analysis, and interpretation of APW paths have been advanced [Irving and Irving, 1982;Harrison and Lindh, 1982;Gordon et al, 1984]. Analyses of true polar wander and comparisons between alternative plate motion systems require accurate knowledge of APW paths for the major lithospheric plates [Livermore et al, 1984;Gordon and Jurdy, 1986;Gordon and Livermore, 1987]. These analyses have great potential for revealing important elements of plate and mantle dynamics as well as geomagnetic field behavior.…”

The scientific work (1957–1987) of Allan Cox

“…I have tried to persuade the reader that Allan's work in geomagnetism and paleomagnetism on one hand and plate tectonics on the other should be viewed as interconnected, arising from a central theme of inquiry into the behavior of the geomagnetic field. His work on absolute plate motions [Gordon et al, 1978] is consistent with this claim because paleomagnetic poles can be reconstructed into an independent (lower mantle) reference frame and used to study true polar wander, a line of enquiry that has been pursued by Gordon [Gordon and Livermore, 1987]. However, since discretion is the better part of valor, it is now appropriate to admit that Allan's work on circum-Pacific tectonics and its relationship to North American geological events like the Laramide orogeny cannot be forced easily into the same structure.…”