Constraints on lithospheric thermal structure for the Indian Ocean from depth and heat flow data

Shoberg, Thomas G.; Stein, Carol A.; Stein, Seth

doi:10.1029/93gl00985

Cited by 20 publications

(7 citation statements)

References 22 publications

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“…The presence of a swell is not as clear on the map. In the Mascarene Basin, the depths are globally lesser (400-500 m) than those predicted by GDH1 [Shoberg et al, 1993]. At its maximum, the amplitude of the swell (peripheral to the additional volcanic material) is about 800-1000 m. On the eastern flank of the Mascarene Ridge, depth is less than on the western flank, but it is generally consistent with the predicted values from the GDH1 model at about 100 km from the Mauritius FZ.…”

Section: Bathymetry and Gravity Datasupporting

confidence: 74%

Heat flow over Reunion hot spot track: Additional evidence for thermal rejuvenation of oceanic lithosphere

Bonneville¹,

Herzen²,

Lucazeau³

1997

J. Geophys. Res.

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Section: Bathymetry and Gravity Datasupporting

confidence: 74%

Heat flow over Reunion hot spot track: Additional evidence for thermal rejuvenation of oceanic lithosphere

Bonneville¹,

Herzen²,

Lucazeau³

1997

J. Geophys. Res.

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“…Some authors (Sclater & Wixon 1986; Hayes 1988; Renkin & Sclater 1988; Marty & Cazanave 1989; Stein & Stein 1992) corrected for sediment loading alone; they observed significantly shallower depths than Parsons & Sclater (1977) but did not consider the bias from igneous crustal thickening or surface warping due to mantle convection. Others excluded seamounts, plateaus and prominent swells such as Hawaii from their data, and consequently estimated a deeper, more plate‐like trend, but did not fully consider the full range of both positive and negative mantle dynamic topography (Shoberg et al 1993; Carlson & Johnson 1994; Doin & Fleitout 1996; Smith & Sandwell 1997; Doin & Fleitout 2000; Hillier & Watts 2005; Zhong et al 2007). Others simply excluded any data within 400–600 km of a past or present hotspot (Heestand & Crough 1981; Schroeder 1984; Korenaga & Korenaga 2008) and consequently observed an even deeper, half‐space trend, but again did not consider negative dynamic topography which tends to occur away from sites of mid‐plate volcanism.…”

Section: Introductionmentioning

confidence: 99%

An analysis of young ocean depth, gravity and global residual topography

Crosby¹,

McKenzie²

2009

Geophysical Journal International

121

116

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S U M M A R YThe variation of ocean depth with age in the absence of crustal thickening and dynamic support places valuable constraints on the thermal and rheological properties of the lithosphere and asthenosphere. We have attempted to estimate this variation using a global data set of shiptracks, with particular emphasis on young ocean floor. In this respect, this paper extends a previous study published in this journal by the same authors, which concentrated on the older parts of the ocean basins. We find that, prior to 80 Ma, subsidence patterns are reasonably consistent, with gradients of 325 ± 20 m Ma −1/2 and zero-age depths of 2600 ± 200 m. There is a strong inverse correlation between zero-age depth and the gradient of depth with the square root of age which is unrelated to local variations in dynamic support. Global depth-age trends to 160 Ma are not significantly different to those for the individual ocean basins. Within corridors of similar basement age, gravity-topography correlations are consistently 30 ± 5 mGal km −1 . Simple isostatic theory and numerical modelling of mantle plumes suggests that, if the minimum depth of convection is defined by the base of the mechanical boundary layer, the admittance should be a function of plate age. The observation that it is not implies that the active convective upwelling beneath young lithosphere ceases at the same depth as it does beneath old oceanic plates. This result is consistent with geochemical modelling of melts near mid-ocean ridges. We have examined the relationship between residual topography and gravity worldwide, and have found that good spatial correlations are restricted to the Atlantic, North Pacific and youngest Indian ocean basins. By contrast, residual topography and gravity are poorly or negatively correlated in the South and young North Pacific Ocean and in the older Indian Ocean. Away from regions of thick crust and flexure, histograms of residual topography and gravity have symmetric distributions about zero. We then use this residual topography to estimate the volume and buoyancy flux of seven major plume swells. In Hawaii, the clear correlation between melt and swell volumes in discrete age corridors is evidence that the horizontal velocity of the hot plume material far downstream from the plume is similar to the plate spreading velocity and that the plume pulses over time. Finally, comparison with seismic tomographic models suggests that the long-wavelength (>2000 km) residual topographic and gravity anomalies have an origin deeper than 250 km. This result is consistent with observations that the admittance is approximately constant at wavelengths longer than 800 km.

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“…6). The predicted depths are somewhat shallower than the predictions of GDH1, presumably because GDH1 (and PSM) were derived using data from the north Atlantic and the north Pacific, whereas the Indian Ocean is shallower (Shoberg et al, 1993). The depth and heatflow predictions for GDH2 may be conveniently and accurately approximated using a half-space model with the same parameters for young lithosphere and the first term of the series solution, with R >> π for older lithosphere (Parsons and Sclater, 1977).…”

Section: Gdh2 Modelmentioning

confidence: 91%

“…The better fit of GDH1, or similar thin-plate models, is robust. It occurs even for depth datasets from which swells are excluded (Shoberg et al, 1993;Kido and Seno, 1994). Satellite geoid data are also diagnostic, because geoid slope, the gradient of the geoid in the direction of increasing lithospheric age, should be constant with age for a half-space model, but in plate models "rolls off" at older ages at a rate depending inversely on plate thickness (Cazenave, 1984; Table 1).…”

Section: Age (Ma)mentioning

confidence: 99%

Hotspots: A view from the swells

DeLaughter¹,

Stein²,

Stein³

2005

Plates, Plumes and Paradigms

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The magnitude of inferred depth and heatflow "anomalies" at hotspot swells relative to "normal" seafloor plays a major role in constraining the causes of these swells. Hotspot heatflow anomalies were first believed to be large and consistent with the uplift expected from thermal thinning of the lower lithosphere. However, these anomalies were overestimated because reference thermal models predicted greater depths and lower heatflow than was typical of lithosphere older than 70 Ma. In contrast, models GDH1 and GDH2, derived by joint fitting of heatflow and bathymetry (and geoid slope for the latter) yield a hotter and thinner lithosphere than previous models and fit depth, heatflow, and geoid data significantly better. Hence heatflow on the Hawaiian and other swells is at most slightly high relative to GDH1 and GDH2. The absence of a significant heatflow anomaly favors a primarily dynamic or compositional rather than thermal swell origin. Similarly, the depths and heatflow for the Darwin rise are consistent with thin-plate models, and thus it is not thermally different from lithosphere of similar age. In younger lithosphere, where observed heatflow is less than that predicted from conduction-only models, the observed heatflow at hotspots can be compared to its global average. The heatflow for the south Pacific superswell is consistent with unperturbed lithosphere, and hence excludes significant lithospheric thermal thinning. Near Iceland, heatflow west of the Mid-Atlantic Ridge is consistent with the global average, but to the east is higher, the opposite of that predicted by models that involve an eastward-migrating plume.

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Constraints on lithospheric thermal structure for the Indian Ocean from depth and heat flow data

Cited by 20 publications

References 22 publications

Heat flow over Reunion hot spot track: Additional evidence for thermal rejuvenation of oceanic lithosphere

Heat flow over Reunion hot spot track: Additional evidence for thermal rejuvenation of oceanic lithosphere

An analysis of young ocean depth, gravity and global residual topography

Hotspots: A view from the swells

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