DI34A-08
The Relative Motion of Pacific Mantle Plumes: Implications for the Viscosity Structure of the Earth’s Mantle.
Wednesday, 16 December 2015: 17:45
301 (Moscone South)
Kevin Konrad1, Anthony A P Koppers2, Bernhard M Steinberger3, Jasper G Konter4, Valerie Finlayson4 and Matthew G Jackson5, (1)Oregon State University, College of Earth, Ocean, and Atmospheric Science, Corvallis, OR, United States, (2)Oregon State University, Corvallis, OR, United States, (3)University of Oslo, Centre for Earth Evolution and Dynamics (CEED), Oslo, Norway, (4)University of Hawaii at Manoa, Department of Geology and Geophysics, Honolulu, HI, United States, (5)University of California Santa Barbara, Department of Earth Sciences, Santa Barbara, CA, United States
Abstract:
The origin of linear, age-progressive hotspot chains have been long attributed to thermal anomalies in the lower mantle. More recently, it has been shown that individual mantle plumes show variable and independent motion. In an effort to assess the relative vectors and magnitudes of plume motion recorded on the Pacific plate we compare the long-lived Hawaii, Louisville and Rurutu hotspot tracks. All three plumes show motion in the modeled age range (0 – 80 Ma) with variable magnitudes related to the proximity of the hotspot from zones of major mantle upwelling as defined primarily by the location of spreading ridges. We compare the observed inter-hotspot distance between tracks through time to the hotspot distances derived through large scale mantle flow and related plume motion modeling. Over 80,000 different hotspot motion model runs with varied viscosity structures, mantle tomography models, and plume starting ages, buoyancies, and depths are compared using a Kolmogorov–Smirnov test to find a mantle structure which best fits the observed inter-hotspot distance data. Preliminary results in particular are most sensitive to the assumed viscosity structure of the Earth’s mantle and thus finding realistic viscosity structures will provide critical and much needed boundary conditions for Earth-like geodynamic modeling.
