Plate Tectonics from the Top-down
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Інститут геофізики ім. С.I. Субботіна НАН України
2010
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| Zitieren: | Plate Tectonics from the Top-down / D. Stegman, W. Schellart, F. Capitanio, R. Farrington // Геофизический журнал. — 2010. — Т. 32, № 4. — С. 174-175. — англ. |
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irk-123456789-1030882016-06-14T03:02:18Z Plate Tectonics from the Top-down Stegman, D. Schellart, W. Capitanio, F. Farrington, R. 2010 Article Plate Tectonics from the Top-down / D. Stegman, W. Schellart, F. Capitanio, R. Farrington // Геофизический журнал. — 2010. — Т. 32, № 4. — С. 174-175. — англ. 0203-3100 http://dspace.nbuv.gov.ua/handle/123456789/103088 en Геофизический журнал Інститут геофізики ім. С.I. Субботіна НАН України |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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DSpace DC |
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English |
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Article |
| author |
Stegman, D. Schellart, W. Capitanio, F. Farrington, R. |
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Stegman, D. Schellart, W. Capitanio, F. Farrington, R. Plate Tectonics from the Top-down Геофизический журнал |
| author_facet |
Stegman, D. Schellart, W. Capitanio, F. Farrington, R. |
| author_sort |
Stegman, D. |
| title |
Plate Tectonics from the Top-down |
| title_short |
Plate Tectonics from the Top-down |
| title_full |
Plate Tectonics from the Top-down |
| title_fullStr |
Plate Tectonics from the Top-down |
| title_full_unstemmed |
Plate Tectonics from the Top-down |
| title_sort |
plate tectonics from the top-down |
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Інститут геофізики ім. С.I. Субботіна НАН України |
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2010 |
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http://dspace.nbuv.gov.ua/handle/123456789/103088 |
| citation_txt |
Plate Tectonics from the Top-down / D. Stegman, W. Schellart, F. Capitanio, R. Farrington // Геофизический журнал. — 2010. — Т. 32, № 4. — С. 174-175. — англ. |
| series |
Геофизический журнал |
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AT stegmand platetectonicsfromthetopdown AT schellartw platetectonicsfromthetopdown AT capitaniof platetectonicsfromthetopdown AT farringtonr platetectonicsfromthetopdown |
| first_indexed |
2025-07-07T13:16:27Z |
| last_indexed |
2025-07-07T13:16:27Z |
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1836994200456921088 |
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Plate Tectonics from the Top-down
D. Stegman1, W. Schellart2, F. Capitanio2,3, R. Farrington3, 2010
1Scripps Institution of Oceanography, University of California, San Diego, La Jolla, USA
dstegman@ucsd.edu
2School of Geosciences, Monash University, Melbourne, Australia
wouter.schellart@monash.edu
3School of Mathematical Sciences, Monash University, Melbourne, Australia
Fabio.capitanio@monash.edu
Rebecca.farrington@monash.edu
Subducting slabs represent the continously re-
cycled cold thermal boundary layer of the Earth's
convecting mantle, and are thought to be the prima-
ry driving force for plate tectonics. Subducted tec-
tonic plates (slabs) sink through the mantle and pull
the plate they are attached to, but this subduction
can be accommodated by two modes: the forward
motion of the subducting plate or backwards mo-
tion of the plate boundary. The latter is the process
of slab rollback and is associated with retreating
trenches.
Over the past decade, both analogue and nu-
merical models of subduction have been developed
which consider the dynamics of a single, isolated
plate sinking into a passive upper mantle. These
models offer a novel way to investigate aspects of
plate tectonics and mantle convection through sin-
gle-sided, asymmetric subduction with a coupled
lithosphere-mantle system, but are restricted to the
upper 1000 km of the mantle and 50 million years
of progressive time-evolution. While such models
assume plates with simplified rheologies, uniform
thickness and uniform density contrasts appropri-
ate for mature oceanic lithosphere, their resultant
3D subduction dynamics are quite rich. The sub-
ducting plate and the sinking slab are coupled
through a stress guide in the middle of the subduc-
ting plate (the strong core) as well as by virtue of
poloidal and toroidal flows induced in the surroun-
ding mantle. We will present the latest generation
of these numerical models and provide an overview
of how these models can be used to investigate the
development of trench curvature, how the subduc-
tion rate is partitioned between forward plate ad-
vance and slab rollback, and how slab morpholo-
gies in the upper mantle are a product of these plate
and trench motions.
As a result of numerous experiments, five dis-
tinct styles of subduction emerge as the entirety of
possible ways a plate can subduct and these have
been quantitatively described in a regime diagram
with predictive capability. We propose that the vari-
ety of subduction regimes are generated primarily
as a direct consequence of the presence of the
modest barrier to flow into the lower mantle. The
regime diagram can be understood from the com-
petition between the weight of the slab and the
strength of the plate, which are related to each other
through an applied bending moment, and this com-
petition produces a particular radius of curvature (for
which we provide a simple scaling theory). Based
on this regime diagram, and observations of the
bending moment at several trenches, we propose
that modern plate tectonics operates entirely within
only 2 of these styles, but we speculate that other
modes may have been the predominant style of
subduction in the Precambrian.
Additionally, for the regime operating on present-
day Earth (the Folding mode), we show that slab
width (W) controls these modes and the partitioning
of subduction between them. Using models from
the Folding regime and a global subduction zone
data set, we show that subducting plate velocity
scales with (W)2/3, whereas trench velocity scales
with 1/W. These findings explain the Cenozoic slow-
down of the Farallon plate and the decrease in sub-
duction partitioning by its decreasing slab width.
The change from Sevier-Laramide orogenesis the
orogenesis to Basin and Range extension in North
America is also explained by slab width; shortening
occurred during wide-slab subduction and overrid-
ing-plate — driven trench retreat, whereas exten-
sion occurred during intermediate to narrow-slab
subduction and slab-driven trench retreat.
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