Comment on “Tectonic rotations in extensional regimes and their paleomagnetic consequences for ocean basalts” by Kenneth L. Verosub and Eldridge M. Moores

One of the more intriguing results from palcomagnetic studies of Deep Sea Drilling Project (DSDP) basalts is that a surprisingly large number of samples have inclinations that deviate significantly from expected values. Vetosub and Moores [1981] sought to account for what appear to be systematic departures of mean inclination at several DSDP basement sites in terms of tectonic rotations along listtic normal faults. Such rotations, about horizontal axes perpendicular to the extension direction and typically amounting to 30ø-50 ø but as large as 70 ø to 90 ø, were suggested to be characteristic of an extensional tectonic regime such as near an ocean spreading ridge system. There is a clear implication that large tectonic rotations are a characteristic process associated with ocean crust formation.