Supercontinent cycles and the calculation of absolute palaeolongitude in deep time

Mitchell, Ross N.; Kilian, Taylor M.; Evans, David A.D.

doi:10.1038/nature10800

Cited by 170 publications

(178 citation statements)

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“…It is, therefore, difficult to differentiate between northsouth plate motion and true polar wander without assuming a specific location of the axis of minimal moment of inertia, I min . For example, Mitchell and colleagues (20) postulated that I min was 90°further to the east during much of the Paleozoic, migrating westward to its present position between 370 and 260 Ma. Their reconstructions, using very different assumptions and "locking" Australia near the equator at 110°E (assumed I min longitude) from 500-390 Ma, may at times show some similarities with ours, but their model features fast plate velocities (except for Australia), and overall, the reconstructed large igneous provinces and kimberlites are uncorrelated with the margins of Tuzo and Jason (only 30% within 10°from their margins).…”

Section: Plate Velocities and Rates Of True Polar Wandermentioning

confidence: 99%

Deep mantle structure as a reference frame for movements in and on the Earth

Torsvik

Voo

Doubrovine

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

229

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Earth's residual geoid is dominated by a degree-2 mode, with elevated regions above large low shear-wave velocity provinces on the core-mantle boundary beneath Africa and the Pacific. The edges of these deep mantle bodies, when projected radially to the Earth's surface, correlate with the reconstructed positions of large igneous provinces and kimberlites since Pangea formed about 320 million years ago. Using this surface-to-core-mantle boundary correlation to locate continents in longitude and a novel iterative approach for defining a paleomagnetic reference frame corrected for true polar wander, we have developed a model for absolute plate motion back to earliest Paleozoic time (540 Ma). For the Paleozoic, we have identified six phases of slow, oscillatory true polar wander during which the Earth's axis of minimum moment of inertia was similar to that of Mesozoic times. The rates of Paleozoic true polar wander (<1°/My) are compatible with those in the Mesozoic, but absolute plate velocities are, on average, twice as high. Our reconstructions generate geologically plausible scenarios, with large igneous provinces and kimberlites sourced from the margins of the large low shear-wave velocity provinces, as in Mesozoic and Cenozoic times. This absolute kinematic model suggests that a degree-2 convection mode within the Earth's mantle may have operated throughout the entire Phanerozoic.plate reconstructions | thermochemical piles T wo equatorial, antipodal, large low shear-wave velocity provinces ( Fig. 1) in the lowermost mantle (1) beneath Africa (termed Tuzo) (2) and the Pacific Ocean (Jason) are prominent in all shear-wave tomographic models (3-7) and have been argued to be related to a dominant degree-2 pattern of mantle convection that has been stable for long times (3). Most reconstructed large igneous provinces and kimberlites over the past 300 My have erupted directly above the margins of Tuzo and Jason, which we term the plume generation zones (1, 2, 5). This remarkable correlation suggests that the two deep mantle structures have been stable for at least 300 My. Stability before Pangea (before 320 Ma) is difficult to test with plate reconstructions because the paleogeography, the longitudinal positions of continents, and the estimates of true polar wander are uncertain (8). It is similarly challenging to reproduce such long-term stability in numerical models (9). However, if the correlation between the eruption sites of large igneous provinces, kimberlites, and the plume generation zones observed for the past 300 Ma has been maintained over the entire Phanerozoic (0-540 Ma), it can provide a crucial constraint for defining the longitudinal positions of continental blocks during Paleozoic time (250-540 Ma).Here we show that a geologically reasonable kinematic model that reconstructs continents in longitude in such a way that large igneous provinces and kimberlites are positioned above the plume generation zones at the times of their formation ( Fig. 2A and SI Appendix, Fig. S2) can be successfully defined f...

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Section: Plate Velocities and Rates Of True Polar Wandermentioning

confidence: 99%

Deep mantle structure as a reference frame for movements in and on the Earth

Torsvik

Voo

Doubrovine

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

229

204

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“…Orthoversion (Mitchell et al 2012;Evans 2003;Li and Zhong 2009) by contrast is a dynamical theory of supercontinental reassembly coupled with large-scale mantle convection. As a dynamical theory, it can and has been tested with numerical simulations (e.g.…”

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confidence: 99%

“…As a dynamical theory, it can and has been tested with numerical simulations (e.g. Zhong et al 2007), as well as by paleomagnetic data (Mitchell et al 2012). Paleomagnetic testing requires additional constraints on paleolongitude, which can be obtained from Cenozoic-Mesozoic plume trails and Paleozoic-Proterozoic true-polar-wander rotation axes (Steinberger and Torsvik 2008;Mitchell et al 2012).…”

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confidence: 99%

“…Zhong et al 2007), as well as by paleomagnetic data (Mitchell et al 2012). Paleomagnetic testing requires additional constraints on paleolongitude, which can be obtained from Cenozoic-Mesozoic plume trails and Paleozoic-Proterozoic true-polar-wander rotation axes (Steinberger and Torsvik 2008;Mitchell et al 2012). Orthoversion postulates that long-lived supercontinents bring about their own destruction through the mantle superswells engendered by continental insulation and absence of slab injections.…”

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confidence: 99%

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The Origin of Laurentia: Rae Craton as the Backstop for Proto-Laurentian Amalgamation by Slab Suction

Hoffman

2014

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Proto-Laurentia (i.e. pre-Grenvillian Laurentia) is an aggregate of six or more formerly independent Archean cratons that amalgamated convulsively in geons 19 and 18 (Orosirian Period), along with non-uniformly distributed areas of juvenile Paleoproterozoic crust. Subduction polarities and collision ages have been provisionally inferred between the major cratons (and some minor ones), most recently between the Rae and Hearne cratons. The oldest Orosirian collisions bound the Rae craton: 1.97 Ga (Taltson-Thelon orogen) in the west, and 1.92 Ga (Snowbird orogen) in the southeast. All other Orosirian collision ages in proto-Laurentia are < 1.88 Ga. The Rae craton was the upper plate during (asynchronous) plate convergence at its western and, tentatively, southeastern margins. Subsequent plate convergence in the Wopmay and Trans-Hudson orogens was complex, with the Rae craton embedded in the lower plate prior to the first accretion events (Calderian, Reindeer and Foxe orogenies), but in the upper plate during major subsequent convergence and terminal collisions, giving rise to the Great Bear and Cumberland magmatic arcs, respectively. The ‘orthoversion’ theory of supercontinental succession postulates that supercontinents amalgamate over geoidal lows within a meridional girdle of mantle downwellings, orthogonal to the lingering superswell at the site of the former supercontinent. If the downwelling nodes develop through positive feedback from the descent of cold oceanic slabs, then viscous traction should contribute to drawing the cratons together over the downwelling node. Viewed in this way, the Rae craton was the first to settle over the downwelling node and became the backstop for the other cratons that were drawn towards it by subduction. It was, literally, the origin of Laurentia. Whether the Rae craton was also the origin of Nuna, the hypothetical cogenetic supercontinent, depends on ages and subduction polarities of Orosirian sutures beyond proto-Laurentia.SOMMAIRELa proto-Laurentie (c.-à-d. la Laurentie pré-grenvillienne) est un agrégat d’au moins six cratons archéens indépendants qui se sont amalgamés convulsivement durant les géons 19 et 18 (Orosirien), le long de zones de croûtes juvéniles paléoprotérozoïques réparties de manière hétérogène. Les polarités de subduction et les âges de collision entre les grands cratons (et d’autres moins grands) ont été provisoirement déduits, le plus récemment entre le craton de Rae et le craton de Hearne. Les plus anciennes collisions orosiriennes ont soudé le craton de Rae : 1,97 Ga (orogène de Taltson-Thelon) dans l’ouest, et 1,92 Ga (orogène de Snowbird) dans le sud-est. Tous les autres âges de collision en proto-Laurentie sont inférieurs à 1,88 Ga. Le craton de Rae constituait la plaque supérieure durant la convergence de plaque (asynchrone) à sa marge ouest, et peut-être aussi à ses marges sud-est. La convergence de plaque subséquente dans les orogènes de Wopmay et Trans-Hudson a été complexe, le craton de Rae étant encastré dans la plaque inférieure avant les premiers événements d’accrétion (orogènes caldérienne, de Reindeer et de Fox), puis dans la plaque supérieure durant la grande convergence subséquente et les collisions terminales, ce qui a créé les arcs magmatiques de Great Bear et de Cumberland respectivement. La théorie de « l’orthoversion » de la succession des supercontinents présuppose que les supercontinents s’amalgament au-dessus de creux géoïdaux en deça d’une gaine méridienne de convections mantéliques descendantes, à angle droit d’un super-renflement persistant au site d’un ancien supercontinent. Si le nœud de convection descendante s’établit par rétroaction positive de la descente de plaques océaniques froides, la traction visqueuse devrait contribuer à entraîner les cratons ensembles au-dessus du nœud de convection descendante. Vu de cette façon, le craton de Rae a été le premier à s’établir au-dessus du nœud de convection descendante, ce qui en a fait la butée des autres cratons entraînés par la subduction. Littéralement, telle a été l’origine de la Laurentie. Quant à savoir si c’est le craton de Rae qui a été à l’origine de Nuna, cet hypothétique surpercontinent cogénétique, cela dépend des âges et des polarités de subduction des sutures orosiriennes au-delà de la proto-Laurentie.

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“…All but one genus, Hubeiscorpio, have been recovered from European and North American strata (Sissom 1990), that at the time of their deposition formed a continuous land mass, Laurasia. Both Laurasia and China situated within tropical to subtropical latitudes during the Silurian and Devo ni an (Scotese & Mckerrow 1990;Mitchell et al 2012).…”

Section: Introductionmentioning

confidence: 99%