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- Title
Hotspot and LLSVP Wander.
- Authors
Tarduno, John; Bono, Richard
- Abstract
Six lines of evidence– paleomagnetism, plate-circuit analyses, sediment facies, geodynamicmodeling, inter-hotspot distance analyses and geochemistry– indicate motion of the Hawaiianplume in Earth’s mantle. Paleomagnetic results from Midway Atoll of the Hawaiian chain arein stark contrast to those from the Emperor seamounts, highlighting the latter as the signatureof southward hotspot drift. The decreasing distance between Hawaii and the Louisville chainseamounts confirms a high rate of drift (∼47 mm yr−1), and excludes true polar wander as afactor relevant to explaining the observations. These findings further indicate that the overallHawaiian-Emperor chain bend morphology was produced by changes in hotspot motion,not plate motion. The rapid southward plume movement was likely produced by acombination of top-down ridge-plume interaction, and bottom-up deep interaction ofplume with the edge of the Pacific Large Low-Shear-Velocity Province (LLSVP)that was being actively deformed by subduction. The Midway paleomagnetic dataindicate that the Hawaiian plume had arrived at its current latitude by 28 Ma. Whencompared versus plate circuit predictions, these data suggest ∼19 mm yr−1 of motionof the surface expression of the African LLSVP (i.e., Indo-Atlantic hotspots) inOligocene to Miocene times (28-10 Ma). More rapid LLSVP apparent motion canoccur due to deformation by subducting slabs. These slow and episodically morerapid rates of motion could lead to thousands of kilometers of net movement of thesurface expression of LLSVPs when viewed on a 100-million-year timescale. Thus,while LLSVPs are ancient (>100 million years old) they are not fixed, but shouldbe expected to continually move as they are affected by deep mantle convection.
- Subjects
HAWAII; LOUISVILLE (Ky.); POLAR wandering; SUBDUCTION; MAGNETIC declination; PALEOMAGNETISM; SEAMOUNTS; CORAL reefs &; islands; FACIES
- Publication
Geophysical Research Abstracts, 2019, Vol 21, p1
- ISSN
1029-7006
- Publication type
Article