Isostatic processes and intracontinental orogenesis

Artemjev, M.E.; Kaban, Mikhail K.

doi:10.1016/0264-3707(91)90031-9

Cited by 15 publications

(6 citation statements)

References 2 publications

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“…McKenzie, 2010). This discrepancy has been attributed to limitations in applying the admittance method for elevated and actively deforming continental areas (Artemjev and Kaban, 1991;Crosby, 2007;Burov, 2011). These difficulties can be avoided by determining Te directly from a predicted distribution of strength (Burov and Diament, 1995).…”

Section: Introductionmentioning

confidence: 92%

“…However, these determinations may be biased by several factors and simplified assumptions, such as that of a homogeneous and continuous plate, and thus often provide inconsistent estimates of Te (e.g. Artemjev and Kaban, 1991). In particular, Te estimates for cratons based on the transfer function (admittance) between the free air gravity and topography are in some cases significantly lower than values obtained from coherence analysis between Bouguer gravity anomalies and topography (e.g.…”

Section: Introductionmentioning

confidence: 95%

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Global strength and elastic thickness of the lithosphere

Tesauro¹,

Kaban²,

Cloetingh³

2012

Global and Planetary Change

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Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 95%

Global strength and elastic thickness of the lithosphere

Tesauro¹,

Kaban²,

Cloetingh³

2012

Global and Planetary Change

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“…The main problem with the determination of T e using cross‐spectral analysis of the gravity field and subsurface load (both admittance and coherence methods) is that this load is often internal, which always leads to big systematic errors of the T e values obtained (Artemjev & Kaban 1991; Macario et al 1995). To overcome this problem we use a method described by Kaban & Mooney (2001) where the admittances are calculated from the gravity model instead of using theoretical formulae.…”

Section: Effective Elastic Plate Thickness Of the Lithospherementioning

confidence: 99%

Nature of the crust-mantle transition zone and the thermal state of the upper mantle beneath Iceland from gravity modelling

Kaban¹,

Flóvenz²,

Pálmason³

2002

Geophysical Journal International

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Summary Gravity data from Iceland and its surroundings are analysed and modelled with respect to seismic data. A Bouguer gravity map of Iceland is recomputed based on admittance between the topography and the gravity and with corrections for glacial ice sheets. From seismic data and with the help of relations between the residual topography and the depth to seismic boundaries we construct maps of the main seismic boundaries, including the Moho. By inversion calculations we recomputed these maps, assuming different density values for Seismic Layer 4 to fit the observed gravity field. We found that the average density of Layer 4 has to be in the range 3050–3150 kg m−3 in order to fit both seismic and gravity data. Thus we conclude that Layer 4 is a transition zone between the mantle and the oceanic crust in Iceland. Furthermore by assuming that the upper‐mantle density variations necessary to compensate for the gravity effect of crustal layers, are caused by thermal variations in the upper mantle, we calculate the depth to the 1200 °C isotherm to be at 30–50 km depth below Iceland but rising up to less than 20 km below parts of the volcanic zone in Northern Iceland. We conclude that the temperature within the Seismic Layer 4 is close to 600 °C at its top, increasing to approximately 950 °C at its bottom (Moho), which makes a widespread layer of partially molten material within Layer 4 unlikely. By use of cross spectral analysis of the gravity field and the external topographic load at short wavelengths, we conclude that the elastic plate thickness in Iceland can hardly exceed 6 km. In addition we point out that the residual isostatic anomalies have circular forms east of the eastern volcanic zone but are near parallel to the ridge axis on the western side. This form of the anomalies may be caused by pressure from the eastward moving mantle plume below the eastern volcanic zone.

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“…However, the results of these studies may be sometimes biased by several factors and simplifying assumptions, such as that the lithosphere consists of a homogeneous and continuous plate. This can lead to inconsistent estimates of T e [ Artemjev and Kaban , ; Kirby , ]. In particular, T e estimates for cratons based on the transfer function (admittance) of the free air gravity and topography are in some cases significantly lower than the values obtained from the coherence analysis of the Bouguer anomalies and topography [ McKenzie , ].…”

Section: Introductionmentioning

confidence: 99%

Variations of the lithospheric strength and elastic thickness in North America

Tesauro

Kaban

Mooney

2015

Geochem Geophys Geosyst

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We evaluate the effect of temperature variations on strength and effective elastic thickness (T e ) of the lithosphere of the North American (NA) continent. To this purpose, we use two thermal models that are corrected for compositional variations and anelasticity effects in the upper mantle. These thermal models are obtained from a joint inversion of gravity data and two recent seismic tomography models (NA07 and SL2013sv). The crustal rheology was defined using NACr14, the most recent NA crustal model. This model specifies seismic velocities and thickness for a three-layer model of the crystalline crust. Strength in the lithosphere and in the crust has similar distributions, indicating that local geotherms play a dominant role in determining strength rather than crustal composition. A pronounced contrast is present in strength between cratonic and off-cratonic regions. Lithospheric strength in the off-cratonic regions is prevalently localized within the crust and T e shows low values (<20 km), while the inner part of the cratons is characterized by a strong lithosphere with large T e (>150 km). In contrast to previous results, our models indicate that Phanerozoic regions located close to the edge of the cratons, as the Appalachians, are characterized by low strength. We also find that locally weak zones exist within the cratons (e.g., beneath the intracratonic Illinois Basin and Midcontinent rift). Seismic tomography models NA07 and SL2013sv differ mainly in some peripheral parts of the cratons, as the Proterozoic Canadian Platform, the Grenville, and the western part of the Yavapai-Mazatzal province, where the integrated strength for the model NA07 is 10 times larger than in model SL2013sv due to a temperature difference (>2008C) in the uppermost mantle. The differences in T e between the two models are less pronounced. In both models, Proterozoic regions reactivated by MesoCenozoic tectonics (e.g., Rocky Mountains and the Mississippi Embayment) are characterized by a weak lithosphere due to the absence of the mechanically strong part of the mantle lithospheric layer. Intraplate earthquakes are distributed along the edges of the cratons, demonstrating that tectonic stress accumulates there, while the cores of the cratons remain undeformed. In both models, intraplate earthquakes occur in weak lithosphere ($0.5 3 10 13 Pa s, T e $ 15 km) or near the edges of strong cratonic blocks, characterized by pronounced contrasts of strength and T e .

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Isostatic processes and intracontinental orogenesis

Cited by 15 publications

References 2 publications

Global strength and elastic thickness of the lithosphere

Global strength and elastic thickness of the lithosphere

Nature of the crust-mantle transition zone and the thermal state of the upper mantle beneath Iceland from gravity modelling

Variations of the lithospheric strength and elastic thickness in North America

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