HR: 0800h
AN: V51B-0541    [Abstracts]
TI: Latitudinal Shift of the Hawaiian Hotspot: Motion Relative to Other Hotspots or True Polar Wander?
AU: * Gordon, R G
EM: rgg@rice.edu
AF: Rice University, 6100 Main St. Earth Science--MS 126, Houston, TX 77005 United States
AU: Horner-Johnson, B C
EM: ben@esci.rice.edu
AF: Rice University, 6100 Main St. Earth Science--MS 126, Houston, TX 77005 United States
AB: Recent results from deep sea drilling confirm a large southward drift of the Hawaiian hotspot since Campanian and Maastrichtian time (ca. 70 to 83 Ma), as was previously found from prior paleomagnetic results from drilling (Kono, 1980; Jackson et al. 1980), from skewness analysis of Pacific magnetic anomalies (Gordon 1982, Petronotis & Gordon 1989, 1999; Petronotis et al. 1992, 1994; Acton & Gordon, 1991; Vasas et al. 1994; Horner-Johnson & Gordon 2003), and from other paleomagnetic and paleolatitude data (Gordon & Cape 1981; Sager & Bleil 1987). This southward drift could have been the result of motion of the Hawaiian hotspot relative to some other hotspots, or of true polar wander, or of both. Tarduno et al. (2003) have recently presented an extreme interpretation of these results as being entirely due to southward motion of the Hawaiian hotspot through the mantle. Here we show that this extreme interpretation is not supported by available data. While the Pacific plate paleomagnetic data are sufficient to show that the Hawaiian hotspot has moved southward relative to the spin axis, alone they cannot be used to demonstrate motion relative to the mantle or relative to other hotspots. To do so, coeval paleomagnetic poles are needed from the continents bordering the Atlantic and Indian Oceans. Here we show that few, if any, of the coeval paleomagnetic poles from the continents incorporated into widely used reference paths pass minimum reliability criteria. Thus, the inference of rapid motion of the Hawaiian hotspot relative to the mantle is surely premature and probably incorrect. We further show that other earlier studies purporting to show motion between hotspots from paleomagnetic data are now invalid because of revisions to paleomagnetic poles from the continents or because of flaws in analysis. Updated paleomagnetic analyses indicate that little motion has occurred between Pacific hotspots and non-Pacific hotspots. Instead, available data are consistent with the hypothesis that the southward motion of the Hawaiian hotspot relative to the spin axis is mainly caused by true polar wander.
DE: 8450 Planetary volcanism (5480)
DE: 9355 Pacific Ocean
DE: 8121 Dynamics, convection currents and mantle plumes
DE: 3040 Plate tectonics (8150, 8155, 8157, 8158)
DE: 1525 Paleomagnetism applied to tectonics (regional, global)
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2004 AGU Fall Meeting