Factors responsible for the high position of the Siberian platform

Grachev, A. F.; Kaban, Mikhail K.

doi:10.1134/s1069351306120032

Cited by 10 publications

(12 citation statements)

References 35 publications

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“…6 shows density estimates derived from Bouguer gravity anomalies computed using gridded freeeair anomalies (Fullea et al, 2008;Sandwell and Smith, 2009), as well as gravity anomalies reduced to the Moho using the adaptive algorithm from Kochnev and Khvostenko (1996). Our results generally agree with those of Grachev and Kaban (2006) for almost all profiles, except for a few local anomalies and the area of the Vilyui basin. The residual anomalies relative to the average gravity field, which characterize the mantle density, are ±60e80 mGal.…”

Section: Discussionsupporting

confidence: 91%

“…The largest gravity low (about À60 mGal) exists beneath the Yakutian kimberlite province. The Moho velocities disagree with two gravity highs of þ70 and þ50 mGal within the eastern Tunguska basin and in the Vilyui basin, respectively, as mentioned by Grachev and Kaban (2006). Our model can explain this discrepancy by the gravity effect of thickness variations in Layer 2, the velocityedensity relationship remaining unchanged.…”

Section: Discussionmentioning

confidence: 37%

“…The situation is similar in West Siberia, where basement subsidence relative to the Egorkin et al, (1987) complemented by Suvorov et al, (2005). Solid line shows Bouguer gravity anomalies; dash and chain lines show residual mantle anomalies computed for the model (B) and borrowed from Grachev and Kaban (2006), respectively. Numerals in (B) are velocities in km/s and respective densities in g cm À3 (in round brackets) after Brocher (2005).…”

Section: Discussionmentioning

confidence: 99%

“…6) consists of two basement layers and sediments (Egorkin et al, 1987), with densities calculated from velocityedensity regression equations (Brocher, 2005). The obtained crustal density patterns can be used to study upper mantle residual gravity anomalies, as in Grachev and Kaban (2006).…”

Section: Discussionmentioning

confidence: 99%

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Seismic and density heterogeneities of lithosphere beneath Siberia: Evidence from the Craton long-range seismic profile

et al. 2015

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The estimate of seismic lithosphere thickness in Siberia remains controversial in spite of long-range controlledesource data available from peaceful nuclear explosions (PNE). Published models of layered upper mantle based on this evidence fail to unambiguously constrain the asthenospheric depth. The observed velocity changes may be due either to vertical layering or to lateral heterogeneity, which are difficult to discriminate because of large (1000 km) PNE spacing. Among the upper mantle models, obtained with reference to Moho velocities derived from higher-resolution chemical explosion data, we focus especially on lateral density heterogeneity. The model reveals three velocity layers, with velocities 8.0e8.5 km/s in Layer 1, 8.6e8.7 km/s in Layer 2, and~8.5 km/s in Layer 3. Layers 2, which varies strongly in thickness, may consist of dense eclogite, judging by the high velocities. Its base may correspond to the base of the lithosphere underlain by the lower-velocity asthenospheric material of Layer 3.The lateral variations in velocity within Layer 1 and in thickness of Layer 2 correlate with major tectonic units: the West Siberian basin, the Tunguska basin with the PermianeTriassic continental flood basalts (the large igneous province of Siberian Traps), as well as the Vilyui basin and the Yakutian kimberlite province. Isostasy in the West Siberian and Vilyui basins results in thick sediments and thin crust, while the large depths of the basement and the intraecrustal discontinuity in the Tunguska basin isostatically compensate the elevated surface topography due to voluminous lavas. The magmatism left its imprint in the mantle as an attenuated "eclogitic layer" beneath the Tunguska basin. However, the available data are still insufficient to understand the exact causes of this attenuation, because mantle conditions may have changed during the elapsed 250 m.y. since then.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 37%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Seismic and density heterogeneities of lithosphere beneath Siberia: Evidence from the Craton long-range seismic profile

et al. 2015

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“…Thus, the conformable downwarping of the basement, middle-crust boundary, and Moho with an amplitude of up to 8-10 km indicates crustal disequilibrium. This fact can be explained by seismic-gravity modeling as a continuation of the studies in (Grachev and Kaban, 2006;Surkov and Morsin, 1993). In (Grachev and Kaban, 2006), a positive gravity anomaly of up to 200 mGal was obtained for mantle lithosphere in an area of near-surface trap distribution, which is also intersected by the Meteorite profile (Fig.…”

Section: Discussionmentioning

confidence: 90%

Seismic inhomogeneities in the upper mantle beneath the Siberian craton (Meteorite profile)

Suvorov

Melnik

Mishenkina

et al. 2013

Russian Geology and Geophysics

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The upper-mantle structure was studied from first-arrival data along the Meteorite profile, run using underground nuclear explosions. Unlike the layered, slightly inhomogeneous models in the previous works, emphasis was laid on lateral inhomogeneity at the minimum possible number of abrupt seismic boundaries. We used forward ray tracing of the traveltimes of refracted and overcritical reflected waves. The model obtained is characterized by considerable velocity variations, from 7.7 km/s in the Baikal Rift Zone to 8.0-8.45 km/s beneath the Tunguska syneclise. A layer of increased velocity (up to 8.5-8.6 km/s), 30-80 km thick, is distinguished at the base of seismic lithosphere. The depth of the layer top varies from 120 km in the northern Siberian craton to 210 km in its southeastern framing. It has been shown that, with crustal density anomalies excluded, the reduced gravity field is consistent with the upper-mantle velocity model.

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Crustal structure of the Siberian craton and the West Siberian basin: An appraisal of existing seismic data

et al. 2013

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Factors responsible for the high position of the Siberian platform

Cited by 10 publications

References 35 publications

Seismic and density heterogeneities of lithosphere beneath Siberia: Evidence from the Craton long-range seismic profile

Seismic and density heterogeneities of lithosphere beneath Siberia: Evidence from the Craton long-range seismic profile

Seismic inhomogeneities in the upper mantle beneath the Siberian craton (Meteorite profile)

Crustal structure of the Siberian craton and the West Siberian basin: An appraisal of existing seismic data

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