Abstract

Cenozoic northward migration of the Pacific plate is documented by magnetization vectors of seamounts and by volcanic lineations resulting from drift over fixed melting spots in the mantle. The rotation with respect to the spin axis of the Earth can also be established from the northward shift with time of the equatorial axis of maximum deposition. Data from Deep Sea Drilling Project sites in the equatorial Pacific indicate a pole of rotation for the past 45 m.y. at lat 67° N., long 59° W., in satisfactory agreement with locations derived from other evidence. The best fit is obtained for an initial rate of 0.25°/m.y., which accelerated to 0.8°/m.y. about 25 m.y. B.P. With this rotation scheme and the subsidence history of the individual drill sites, the paleobathymetric evolution of the central equatorial Pacific during Cenozoic time and the position of the ancestral East Pacific Rise can be established.

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