Waveform tomography reveals channeled flow at the base of the oceanic asthenosphere
French, S.; Lekic, V.; Romanowicz, R. (2013). Waveform tomography reveals channeled flow at the base of the oceanic asthenosphere. Science (Wash.) 342(6155): 227-230. http://dx.doi.org/10.1126/science.1241514
In: Science (Washington). American Association for the Advancement of Science: New York, N.Y. ISSN 0036-8075; e-ISSN 1095-9203, meer
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| Auteurs | | Top |
- French, S.
- Lekic, V.
- Romanowicz, R.
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| Abstract |
Understanding the relationship between different scales of convection that drive plate motions and hotspot volcanism still eludes geophysicists. Using full-waveform seismic tomography, we imaged a pattern of horizontally elongated bands of low shear velocity, most prominent between 200 and 350 kilometers depth, which extends below the well-developed low-velocity zone. These quasi-periodic fingerlike structures of wavelength ~2000 kilometers align parallel to the direction of absolute plate motion for thousands of kilometers. Below 400 kilometers depth, velocity structure is organized into fewer, undulating but vertically coherent, low-velocity plumelike features, which appear rooted in the lower mantle. This suggests the presence of a dynamic interplay between plate-driven flow in the low-velocity zone and active influx of low-rigidity material from deep mantle sources deflected horizontally beneath the moving top boundary layer. |
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