Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 25 February 1994:
Vol. 263. no. 5150, pp. 1105 - 1111
DOI: 10.1126/science.263.5150.1105
Prev | Table of Contents | Next

Articles

Trench-Parallel Flow Beneath the Nazca Plate from Seismic Anisotropy

R. M. Russo 1 and P. G. Silver 1

1 Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015, USA.

Shear-wave splitting of S and SKS phases reveals the anisotropy and strain field of the mantle beneath the subducting Nazca plate, Cocos plate, and the Caribbean region. These observations can be used to test models of mantle flow. Two-dimensional entrained mantle flow beneath the subducting Nazca slab is not consistent with the data. Rather, there is evidence for horizontal trench-parallel flow in the mantle beneath the Nazca plate along much of the Andean subduction zone. Trench-parallel flow is attributale utable to retrograde motion of the slab, the decoupling of the slab and underlying mantle, and a partial barrier to flow at depth, resulting in lateral mantle flow beneath the slab. Such flow facilitates the transfer of material from the shrinking mantle reservoir beneath the Pacific basin to the growing mantle reservoir beneath the Atlantic basin. Trenchparallel flow may explain the eastward motions of the Caribbean and Scotia sea plates, the anomalously shallow bathymetry of the eastern Nazca plate, the long-wavelength geoid high over western South America, and it may contribute to the high elevation and intense deformation of the central Andes.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Subducted oceanic asthenosphere and upper mantle flow beneath the Juan de Fuca slab.
R.M. Russo (2009)
Lithosphere 1, 195-205
   Abstract »    Full Text »    PDF »
Overriding plate shortening and extension above subduction zones: A parametric study to explain formation of the Andes Mountains.
W.P. Schellart (2008)
Geological Society of America Bulletin 120, 1441-1454
   Abstract »    Full Text »    PDF »
Strong plate coupling along the Nazca-South America convergent margin.
G. Iaffaldano and H.-P. Bunge (2008)
Geology 36, 443-446
   Abstract »    Full Text »    PDF »
The Subduction Zone Flow Field from Seismic Anisotropy: A Global View.
M. D. Long and P. G. Silver (2008)
Science 319, 315-318
   Abstract »    Full Text »    PDF »
Trench-Parallel Anisotropy Produced by Foundering of Arc Lower Crust.
M. D. Behn, G. Hirth, and P. B. Kelemen (2007)
Science 317, 108-111
   Abstract »    Full Text »    PDF »
Slab disruption, mantle circulation, and the opening of the Tyrrhenian basins.
C. Faccenna, F. Funiciello, L. Civetta, M. D'Antonio, M. Moroni, and C. Piromallo (2007)
Geological Society of America Special Papers 418, 153-169
   Abstract »    Full Text »    PDF »
Global kinematics in deep versus shallow hotspot reference frames.
M. Cuffaro and C. Doglioni (2007)
Geological Society of America Special Papers 430, 359-374
   Abstract »    Full Text »    PDF »
Curvature of oceanic arcs.
G. Morra, K. Regenauer-Lieb, and D. Giardini (2006)
Geology 34, 877-880
   Abstract »    Full Text »    PDF »
Postcollisional contractional and extensional deformation in the Aegean region.
S. Kokkalas, P. Xypolias, I. Koukouvelas, and T. Doutsos (2006)
Geological Society of America Special Papers 409, 97-123
   Abstract »    Full Text »    PDF »
Ongoing compression across South American plate: observations, numerical modelling and some implications for petroleum geology.
C. Lima (2003)
Geological Society, London, Special Publications 209, 87-100
   Abstract »    PDF »
Back-arc spreading and mantle flow in the East Scotia Sea.
R. Livermore (2003)
Geological Society, London, Special Publications 219, 315-331
   Abstract »    PDF »
Hot orogens, tectonic switching, and creation of continental crust.
W.J. Collins (2002)
Geology 30, 535-538
   Abstract »    Full Text »    PDF »
Seismic Anisotropy: Tracing Plate Dynamics in the Mantle.
J. Park and V. Levin (2002)
Science 296, 485-489
   Abstract »    Full Text »    PDF »
The Mantle Flow Field Beneath Western North America.
P. G. Silver and W. E. Holt (2002)
Science 295, 1054-1057
   Abstract »    Full Text »    PDF »
Seismic Anisotropy and Global Geodynamics.
J.-P. Montagner and L. Guillot (2002)
Reviews in Mineralogy and Geochemistry 51, 353-385
   Full Text »    PDF »
Evidence for shear-wave anisotropy in the mantle wedge beneath south central Alaska.
S. Wiemer, G. Tytgat, M. Wyss, and U. Duenkel (1999)
Bulletin of the Seismological Society of America 89, 1313-1322
   Abstract »    PDF »
The kinematics of back-arc basins, examples from the Tyrrhenian, Aegean and Japan Seas.
L. Jolivet, C. Faccenna, N. D'Agostino, M. Fournier, and D. Worrall (1999)
Geological Society, London, Special Publications 164, 21-53
   Abstract »    PDF »
On the origin of west-directed subduction zones and applications to the western Mediterranean.
C. Doglioni, E. Gueguen, P. Harabaglia, and F. Mongelli (1999)
Geological Society, London, Special Publications 156, 541-561
   Abstract »    PDF »
Coupling of South American and African Plate Motion and Plate Deformation.
P. G. Silver, R. M. Russo, and C. Lithgow-Bertelloni (1998)
Science 279, 60-63
   Abstract »    Full Text »
... But Did Deeper Forces Act To Uplift the Andes?.
R. A. Kerr (1995)
Science 269, 1215-1216
   PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)