Time scales and heterogeneous structure in geodynamic earth models

Science

Volumn 280, Issue 5360, 1998, Pages 91-95

  Bunge, Hans Peter ^a   Richards, Mark A ^b   Lithgow Bertelloni, Carolina ^c   Baumgardner, John R ^d   Grand, Stephen P ^e   Romanowicz, Barbara A ^b  

^a INSTITUT DE PHYSIQUE DU GLOBE DE PARIS   (France)

^b UNIVERSITY OF CALIFORNIA   (United States)

^c UNIVERSITY OF MICHIGAN   (United States)

^d LOS ALAMOS NATIONAL LABORATORY   (United States)

^e UNIVERSITY OF TEXAS AT AUSTIN   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

GEODYNAMICS; MANTLE CONVECTION; PLATE MOTION; SEISMIC TOMOGRAPHY; SUBDUCTION;

ARTICLE; ASTRONOMY; COMPUTER MODEL; PRIORITY JOURNAL;

EID: 0032478690     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.280.5360.91     Document Type: Article

References (37)

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25. The plate tectonic information consists of 11 plate-motion stages extending back to 119 Ma. During a stage, plate motions are relatively constant. Stage boundaries correspond to episodes of large or sudden changes in plate motions, that is, plate rearrangements. Plate stage information consists of the complete plate boundaries for all the major plates and the Euler rotation vectors of each plate. The first six plate stages (0 to 10, 10 to 25, 25 to 43, 43 to 48, 48 to 56, and 56 to 64 Ma) span the Cenozoic and are based on the global plate boundaries and rotation poles of Gordon and Jurdy (30); the remaining five Mesozoic plate stages (64 to 74, 74 to 84, 84 to 94, 94 to 100, and 100 to 119) are based on the global compilation of Lithgow-Bertelloni and Richards (31). All plate boundaries and rotation poles are in the hotspot reference frame. The inherent uncertainties associated with using plate tectonic information in geodynamic models are described in (31). Many of the Mesozoic reconstructions, particularly for plates that have disappeared (Izanagi, Phoenix, Kula) or are in the process of disappearing (Farallon), are only approximate, especially the positions of subduction zones and to a lesser extent the rotation poles.
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31. This CMB response time is accelerated by a factor of 2, relative to a model without core heating.
32. The correspondence of the mantle response time and the time period for reliable reconstructions is not coincidental. Reconstructions are largely dependent on the magnetic isochrons of sea-floor spreading, which is limited to the characteristic maximum age for oceanic lithosphere. Simple boundary-layer convection theory (22) predicts that this characteristic boundary-layer age should be similar to the vertical transit time for convection. Based on the prediction that advection velocities scale roughly with the natural logarithm of the viscosity contrast (78), the mantle response time should be accurate within a factor of 2.
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34. H.-P. Bunge et al., data not shown.
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37. We thank G. Davies and R. van der Hilst for constructive reviews, J. Painter for supporting the 3D graphics, and the Los Alamos Branch of the Institute of Geophysics and Planetary Physics for continuing support. Computing resources were provided by the Advanced Computing Laboratory of Los Alamos National Laboratory.