HR: 17:00h
AN: U34A-05    [Abstracts]
TI: Motion of Pacific mantle plumes
AU: Cottrell, R D
EM: rory@earth.rochester.edu
AF: University of Rochester, Department of Earth & Environmental Sciences, 227 Hutchison Hall, Rochester, NY 14627, United States
AU: * Tarduno, J A
EM: john@earth.rochester.edu
AF: University of Rochester, Department of Earth & Environmental Sciences, 227 Hutchison Hall, Rochester, NY 14627, United States
AU: Doubrovine, P V
EM: pavel@earth.rochester.edu
AF: University of Rochester, Department of Earth & Environmental Sciences, 227 Hutchison Hall, Rochester, NY 14627, United States
AB: The Hawaiian--Emperor hotspot chain, and its distinctive bend at 47 Ma, have figured prominently in the development of ideas on the nature of mantle plumes, plate motion, and frames of reference. However, paleomagnetic data from Ocean Drilling Program (ODP) Leg 197, together with results from plate circuit and geodynamic modeling studies, indicate southward motion of the Hawaiian hotspot during formation of the Emperor Seamounts. These analyses confirm the idea that mantle plumes should be influenced by mantle flow, and that such motion must be considered when constructing frames of reference for plate motion. An important corollary of this finding on hotspot motion is that long-term polar wander of Earth, which has been inaccurately assessed by viewing paleomagnetic data in a fixed hotspot reference frame, has been far less than previously thought. Here we extend the ODP Leg 197 analysis in three ways. We examine i. paleomagnetic data and their uncertainties relative to volcanic propagation rates; ii. consistency tests of plate circuit models and global paleomagnetic data and iii. intra-basin motion of plumes through new analyses of Late Cretaceous lavas from New Zealand. The first analysis suggests that while Late Cretaceous--Paleogene hotspot motion was the dominant factor in forming the Emperor track (and thus the famous bend morphology), smaller- scale plate motion changes might still be preserved in the track. The second set of analyses help point to deficiencies in the global paleomagnetic data set, whereas the third highlights that motion between groups of hotspots is a dominant feature during mid-Cretaceous to Paleogene times.
DE: 1525 Paleomagnetism applied to tectonics: regional, global
DE: 1532 Reference fields: regional, global
DE: 8120 Dynamics of lithosphere and mantle: general (1213)
SC: Union [U]
MN: 2007 Fall Meeting