HR: 1340h
AN: U13A-0870    [Abstracts]
TI: Plate circuit reconstructions and the consistency between Pacific and non-Pacific paleomagnetic reference frames in Late Cretaceous to Paleogene times (80--50 Ma)
AU: * Doubrovine, P V
EM: pavel@earth.rochester.edu
AF: University of Rochester, Earth and Environmental Sciences, Hutchison Hall 227, University of Rochester, Rochester, NY 14627, United States
AU: Tarduno, J A
EM: john@earth.rochester.edu
AF: University of Rochester, Earth and Environmental Sciences, Hutchison Hall 227, University of Rochester, Rochester, NY 14627, United States
AB: Reconstructions of the Pacific plate relative to those bordering the Atlantic and Indian oceans have traditionally relied on the use of the fixed hot spot reference frame. However, ~13° of Hawaiian hot spot southward migration in the Late Cretaceous and Paleogene (81--47~Ma) recorded by paleomagnetic inclination data from the Emperor Seamounts, plate circuit reconstructions and simulations of convective mantle flow consistently suggest rapid motion between the Pacific and Indo-Atlantic hot spot groups during this time interval. This provides motivation to reexamine the history of Pacific plate motion with respect to the plates of the Indo-Atlantic realm using plate circuit reconstructions. Comparisons of Late Cretaceous to Paleogene paleomagnetic data from the Emperor Seamounts with non-Pacific reference poles reconstructed to the Pacific plate provide valuable insights both into veracity of plate circuit reconstructions and the resolution of paleomagnetic data sets. Here we present two alternative kinematic models based on the most recent and reliable plate-pair reconstructions linking the Pacific and Indo-Atlantic plates through a series of active and fossil spreading ridges: one running through West to East Antarctica, and another through the Lord Howe Rise to Australia. We find good agreement between Late Cretaceous (~75--80~Ma) Pacific and non-Pacific data that attests to the accuracy of the paleomagnetic estimates and plate circuit reconstructions. However, paleomagnetic data lack the resolution necessary to distinguish between the two alternative plate circuit models. In contrast, small discrepancies were observed in some comparisons of Paleogene data sets (~55--60~Ma). It will be argued that these differences reflect a systematic bias in average non-Pacific poles and/or minor non-dipole field contributions rather than errors in the plate circuits. The possible sources of these biases will be discussed.
DE: 1525 Paleomagnetism applied to tectonics: regional, global
DE: 1527 Paleomagnetism applied to geologic processes
DE: 3040 Plate tectonics (8150, 8155, 8157, 8158)
DE: 8157 Plate motions: past (3040)
SC: Union [U]
MN: 2007 Fall Meeting