Planform of mantle convection beneath the Pacific Ocean

McKenzie, Dan; Watts, A. B.; Parsons, B.; Roufosse, Micheline C.

doi:10.1038/288442a0

Cited by 151 publications

(67 citation statements)

References 21 publications

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“…Davies' (1981) model of regional compensation of subducting slabs includes supporting stresses transmitted both up the slab and through the surrounding mantle. Just as the preceding models do, this model produces a net geoid io,v (see dashed line in Figure 4, Davies, 1981) for the case of complete compensation, i.e., the case in which the magnitude of the supporting forces equals that of the sinking forces A corner I'low model like the one used by Tovish et al (1978), Stevenson and 'Turner (1977) or McKenzie (1969) represents the kinematics of subduction more exactly than does either the sinking cylinder model (Morgan, 1965) or the convection/blob model (McKenzie et al, 1980). Tovish et al (1978) demonstrated that the induced flow in the mantle gives rise to dynamic pressures on the slab which may substantially counterbalance the gravitational torque on the slab.…”

Section: Introductionmentioning

confidence: 99%

On the compensation of geoid anomalies due to subducting slabs

McAdoo¹

1982

J. Geophys. Res.

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Candidate models of the forces which oppose the sinking of slabs are all constrained to produce results consistent with the following observation: relative geoid highs, which one assumes are due to slabs, characteristically occur over subduction zones. Certain models which are otherwise plausible, such as those based on a Newtonian half-space mantle, yield geoid lows instead of highs. This study has extended a published model of viscous corner flow in subduction zones in ordl.r to demonstrate that it can -in certain cases -produce the requisite geoid highs. Specifically the relative geoid highs ar.-produced if mantle flow is distinctly non-Newtonian (stress exponent n > 2). Results in the form of deflection of vertical (or geoid slope) profiles are cony puted for typical values of the slab parameters; they are compared with a representative profile of geoid slopes derived from Seasat altimeter data in order to show qualitative similarities. It is concluded that the effect of non-Newtonian flow as opposed to Newtonian, is to spread out the induced surface deformation, thereby stretching out the regional compensation to waverengths.(transverse to the trench) of several thousand kilometers. r iii

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Section: Introductionmentioning

confidence: 99%

On the compensation of geoid anomalies due to subducting slabs

McAdoo¹

1982

J. Geophys. Res.

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“…In general, low GTR values (0-2 m/km) indicate shallow level of compensation, whereas, the intermediate GTR values (2-6 m/km) suggest that the compensation takes place at deeper level by lithosphere thinning (Crough, 1978). Conversely, higher GTR values (> 6 m/km) indicate compensation below the lithosphere supported by convective stresses (McKenzie et al, 1980).…”

Section: Geoid-topography Ratio (Gtr)mentioning

confidence: 99%

Lithosphere structure and upper mantle characteristics below the Bay of Bengal

et al. 2016

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SUMMARY:The oceanic lithosphere in the Bay of Bengal (BOB) formed 80 -120 Ma following the breakup of eastern Gondwanaland. Since its formation, it has been affected by the emplacement of two long N-S trending linear aseismic ridges (85 o E and Ninetyeast) and by the loading of ca.20-km of sediments of the Bengal Fan. Here, we present the results of a combined spatial and spectral domain analysis of residual geoid, bathymetry and gravity data constrained by seismic reflection and refraction data. Self-consistent geoid and gravity modeling defined by temperature-dependent mantle densities along a N-S transect in the BOB region revealed that the depth to the Lithosphere-Asthenosphere boundary (LAB) deepens steeply from 77 km in the south to 127 km in north, with the greater thickness being anomalously thick compared to the lithosphere of similar-age beneath the Pacific Ocean. The Geoid-Topography Ratio (GTR) analysis of the 85°E and Ninetyeast ridges indicate that they are compensated at shallow depths.

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“…the mean), usually implemented as a 'sliding window' or 'kernel' filter such as the boxcar (e.g. Watts, 1976;McKenzie et al, 1980, Wessel & Smith, 1998. However if normal elevations are rare, perhaps where there are many volcanoes and little remaining original seafloor, bias can occur underestimating heights and volumes in the residual (Smith, 1990).…”

Section: Regional-residual Separationmentioning

confidence: 99%

“…Watts, 1976;McKenzie et al, 1980;Hillier & Smith, 2008), a trend representative of a region was calculated first and then subtracted to leave the 'residual'. Alternatively, it is possible to directly isolate (i.e.…”

Section: Regional-residual Separationmentioning

confidence: 99%

3.11 Geovisualization

Smith

Hillier²,

Otto³

et al. 2013

Treatise on Geomorphology

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Synopsis (50-100 words)Geovisualisation, the depiction of spatial data, is key to facilitating the generation of observational datasets through which Earth surface and solid Earth processes may be understood. This chapter focuses upon the visualisation of terrain morphology using satellite imagery and DEMs, where manual interpretation remains prevalent in the study of geomorphic processes. Techniques to enhance satellite images and DEMs in order to improve landform identification as part of the manual mapping process are presented. Visual interaction with spatial data is an important part of exploring and understanding geomorphological datasets and a variety of methods ranging from simple overlay, panning and zooming are discussed, along with 2.5D, 3D and temporal analyses. Visualisation outputs are outlined in the final section, which focuses on static and interactive methods of dissemination. Geomorphological mapping legends and the cartographic principles for map design are introduced, followed by details of dynamic webmap systems that allow a greater immersive use by end users, as well as the dissemination of data.

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Planform of mantle convection beneath the Pacific Ocean

Cited by 151 publications

References 21 publications

On the compensation of geoid anomalies due to subducting slabs

On the compensation of geoid anomalies due to subducting slabs

Lithosphere structure and upper mantle characteristics below the Bay of Bengal

3.11 Geovisualization

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