Spherical disharmonies in the Earth sciences and the spatial solution: Ridges, hotspots, slabs, geochemistry and tomography correlations

Ray, Terrill W.; Anderson, Don L.

doi:10.1029/94jb00340

Cited by 44 publications

(24 citation statements)

References 28 publications

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“…This approach, very simple from the formal point of view, has many pitfalls which can be avoided through the use of spatial domain correlations (RAY and ANDERSON, 1994). For reasons explained in previous papers (KÝ VALOVÁ et al, 1995;Č ADEK et al, 1994), we prefer the spatial correlation formula based on integrating the seismic heterogeneity t(d, q, ) at a depth d along the subduction line L: Figure 1 Average location of subduction zones used in this paper.…”

Section: Datamentioning

confidence: 99%

“…In order to quantify the significance of the correlation, we evaluated the confidence level corresponding to correlation coefficient c. There is no general formula for evaluating the confidence level in the case of spatial domain correlations. The simplest technique for determining the confidence level is the Monte Carlo test (see, e.g., RAY and ANDERSON, 1994) which is based on the statistical evaluation of a large set of correlation coefficients obtained for randomly rotated functions L and t. One of the functions (t in our case) was randomly rotated and the correlation between subduction L and the rotated function t was computed from eq. (1).…”

Section: Datamentioning

confidence: 99%

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Regional Correlation Analysis between Seismic Heterogeneity in the Lower Mantle and Subduction in the Last 180 Myr: Implications for Mantle Dynamics and Rheology

Čı́žková

Čadek

Slancová³

1998

Pure appl. geophys.

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We have carried out a regional correlation analysis between the seismic structure of the lower mantle and the reconstructions of subduction sites in the past 180 Myr with the aim of estimating individual styles of slab motion over different parts of the earth. The correlation patterns obtained for three subduction branches (West Pacific, East Pacific and Alpine-Himalayan) are remarkably different. In the West Pacific, the subducting slabs tend to be stagnant beneath the 660-km discontinuity, while basically no subducted lithosphere has been detected below the depth of 1000 km. In contrast, the lithosphere subducted beneath the Americas seems to penetrate through the lower mantle continuously, showing correlation peaks at depth intervals of 800 -1100 km and 1900 -2500 km. In the AlpineHimalayan region, significant correlation has been found below the 660-km discontinuity for recent subduction and in the mid-mantle for subduction younger than 120 Myr. An increase in the correlation close to the core-mantle boundary nevertheless indicates that, under certain circumstances, the slabs can reach the bottom of the mantle in the West Pacific and in the Alpine-Himalayan regions as well. The correlation peak at a depth of around 1000 km is common to all the subduction branches. However, its depth rather varies for different subduction zones and, thus, it is not clear whether this correlation maximum may be associated with a global mid-mantle discontinuity.

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Section: Datamentioning

confidence: 99%

Section: Datamentioning

confidence: 99%

Regional Correlation Analysis between Seismic Heterogeneity in the Lower Mantle and Subduction in the Last 180 Myr: Implications for Mantle Dynamics and Rheology

Čı́žková

Čadek

Slancová³

1998

Pure appl. geophys.

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“…Ray and Anderson, 1994). For example, if the predicted location of a subducted slab is only slightly higher or lower than observed through tomography, or -in other words -at the same depth is slightly offset to the side, correlation may be low, although the pattern may be quite similar.…”

Section: Ways Of Comparison Between Geodynamic and Tomographic Modelsmentioning

confidence: 99%

“…We both visually compare along cross sections and compute formal correlations (cf. Ray and Anderson, 1994;Becker and Boschi, 2002). Our work is essentially an update of Steinberger (2000), which we believe is appropriate now, as both models of seismic tomography and subduction history have changed since then.…”

Section: B Steinberger Et Al: Subduction To the Lower Mantle -Compamentioning

confidence: 99%

Subduction to the lower mantle – a comparison between geodynamic and tomographic models

2012

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Abstract. It is generally believed that subduction of lithospheric slabs is a major contribution to thermal heterogeneity in Earth's entire mantle and provides a main driving force for mantle flow. Mantle structure can, on the one hand, be inferred from plate tectonic models of subduction history and geodynamic models of mantle flow. On the other hand, seismic tomography models provide important information on mantle heterogeneity. Yet, the two kinds of models are only similar on the largest (1000 s of km) scales and are quite different in their detailed structure. Here, we provide a quantitative assessment how good a fit can be currently achieved with a simple viscous flow geodynamic model. The discrepancy between geodynamic and tomography models can indicate where further model refinement could possibly yield an improved fit. Our geodynamical model is based on 300 Myr of subduction history inferred from a global plate reconstruction. Density anomalies are inserted into the upper mantle beneath subduction zones, and flow and advection of these anomalies is calculated with a spherical harmonic code for a radial viscosity structure constrained by mineral physics and surface observations. Model viscosities in the upper mantle beneath the lithosphere are ∼10 20 Pas, and viscosity increases to ∼10 23 Pas in the lower mantle above D " . Comparison with tomography models is assessed in terms of correlation, both overall and as a function of depth and spherical harmonic degree. We find that, compared to previous geodynamic and tomography models, correlation is improved, presumably because of advances in both plate reconstructions and mantle flow computations. However, high correlation is still limited to lowest spherical harmonic degrees. An important ingredient to achieve high correlation -in particular at spherical harmonic degree two -is a basal chemical layer. Subduction shapes this layer into two rather stable hot but chemically dense "piles", corresponding to the Pacific and African Large Low Shear Velocity Provinces. Visual comparison along cross sections indicates that sinking speeds in the geodynamic model are somewhat too fast, and should be 2 ± 0.8 cm yr −1 to achieve a better fit.

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“…Most of the Earth's ridges and active oceanic volcanoes are in this half of the Earth, which also corresponds to that part of the mantle which has not been cooled by the integrated effects of subduction (Ray & Anderson 1994;Scrivner & Anderson 1992;Anderson 1996). It is likely that the lithosphere is under extension in at least some of these regions.…”

Section: Temperatures In the Mantlementioning

confidence: 98%

A theory of the Earth: Hutton and Humpty Dumpty and Holmes

Anderson¹

1999

Self Cite

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Paradoxes can be viewed as a bother or as a rich source of information. Paradoxes, fallacies and logical inconsistencies, along with the unstated assumptions behind old worldviews often form the foundation for a new worldview. This is where science differs from myth and just-so stories.Mantle dynamicists and geochemists have developed a worldview that, in many respects, is incompatible with modern theories of planetary accretion, geodynamics and geophysics, and with the geological context of volcanoes. A primordial undegassed mantle, as both the furnace and the fuel of midplate volcanoes, occupies a central role in the geochemical models. Although modern data alone are sufficient to overturn this view, it is interesting to address it in terms of its own assumptions, fallacies and inconsistencies, and the history of ideas. This is a vast field, so, in honour of James Hutton, I focus on volcanoes, their products, their causes and their sources.The following axioms are developed which point toward a different kind of world from the pristine primordial worldviews and the plume paradigm.9 Linear volcanic chains delineate the stress field, not the displacement field, of the lithosphere. 9 Lithospheric architecture, not the core-mantle boundary, dictates the planform of convection in the mantle. 9 Incipient melting is the normal state of the upper mantle. 9 The lower mantle is depleted in the heat producing elements compared to the crust, upper mantle and the bulk silicate Earth. 9 The Earth is depleted in volatile elements. 9 High 3He/4He ratios in mantle materials imply a deficit of 4He. 9 Primordial heat contributes a significant part of the Earth's heat flow.These axioms [A] are the inverse of the assumptions of the plume and primordial mantle paradigms [not-A] and the new and the old views are to each other as lookingglass worlds. An 'axiom' is a self-evident truth or an established rule. It is also an undemonstrated proposition concerning an undefined set of elements and relationships. The above 'axioms' [A] are not true axioms but [not-A] provide the axiomatic framework of the current world model. These [not-A] propositions are treated as self-evident truths so [A] can also be called axioms, even though they are falsifiable. The prevailing worldview, the 'standard model', attributes both melting and volcanic chains to deep mantle upwellings controlled by the bottom of the system with most of the original radioactivity and volatile inventory of the Earth in the deep mantle. This is not only inconsistent with modern data but also with the previous worldview embedded in the axioms. These axioms have not been pushed out by better ideas, or falsified; they have simply been overlooked or forgotten. Mantle dynamics is controlled from the top, not the bottom. ANDERSON, D. L. 1999. A theory of the Earth: Hutton and Humpty Dumpty and Holmes.

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Spherical disharmonies in the Earth sciences and the spatial solution: Ridges, hotspots, slabs, geochemistry and tomography correlations

Cited by 44 publications

References 28 publications

Regional Correlation Analysis between Seismic Heterogeneity in the Lower Mantle and Subduction in the Last 180 Myr: Implications for Mantle Dynamics and Rheology

Regional Correlation Analysis between Seismic Heterogeneity in the Lower Mantle and Subduction in the Last 180 Myr: Implications for Mantle Dynamics and Rheology

Subduction to the lower mantle – a comparison between geodynamic and tomographic models

A theory of the Earth: Hutton and Humpty Dumpty and Holmes

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