HR: 09:00h
AN: GP21A-03 INVITED     [Abstracts]
TI: Hotspot motion, paleomagnetic tests of plate circuits,and coherency of the Pacific plate
AU: * Tarduno, J A
EM: john@earth.rochester.edu
AF: Department of Earth and Environmental Sciences, 227 Hutchison Hall University of Rochester, Rochester, NY 14627 United States
AU: Cottrell, R D
EM: rory@earth.rochester.edu
AF: Department of Earth and Environmental Sciences, 227 Hutchison Hall University of Rochester, Rochester, NY 14627 United States
AU: Doubrovine, P V
EM: pavel@earth.rochester.edu
AF: Department of Earth and Environmental Sciences, 227 Hutchison Hall University of Rochester, Rochester, NY 14627 United States
AU: Madoff, R
EM: risa@earth.rochester.edu
AF: Department of Earth and Environmental Sciences, 227 Hutchison Hall University of Rochester, Rochester, NY 14627 United States
AB: Paleomagnetic analyses conducted during Ocean Drilling Program (ODP) Leg 197, studies of plate circuits and geodynamic modeling results have all pointed toward motion of the Hawaiian hotspot during formation of the Emperor Seamounts. Here we examine plate circuits that transfer data to the Pacific basin through West Antarctica (e.g. Cande et al., 1995) and through the Lord Howe Rise (Steinberger et al., 2004). We find that both circuits pass paleomagnetic consistency tests and yield hotspot motion rates that are compatible with ODP Leg 197 data based on rigorous rock magnetic and paleomagnetic investigations. An important part of this evaluation is the recognition that prior Pacific apparent polar wander paths (APWPs) fail internal consistency tests, and that the physical processes derived from these paths, including rates of true polar wander, are untenable. The failure of prior Pacific APWPs can be traced to an overreliance on remote sensing data (modeling of seamount anomalies and marine magnetic anomaly skewness) and an underappreciation of the inherent limitations of such data. Differences between paleomagnetic confidence intervals and those typically portrayed for remote sensing data will be briefly reviewed. Notwithstanding the elegance of some technical analyses, remote sensing data are clearly past their prime in terms of answering topical questions regarding hotspots and mantle plumes. Similarities between the Hawaiian-Emperor and Louisville tracks of the Pacific plate suggest that the hotspot motion defined by the ODP Leg 197 paleomagnetic data may reflect basin-wide flow. New age data, however, also point toward intra-basin hotspot motion and/or lithospheric control on hotspot tracks. We also test coherency of the Pacific plate since the Late Cretaceous to evaluate the degree to which intra-plate deformation could have affected hotspot tracks.
DE: 1520 Magnetostratigraphy
DE: 1525 Paleomagnetism applied to tectonics (regional, global)
DE: 3040 Plate tectonics (8150, 8155, 8157, 8158)
DE: 8157 Plate motions--past (3040)
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2005 Joint Assembly