Asymmetric upwarp of the asthenosphere beneath the Baikal rift zone, Siberia

Gao, Stephen S.; Davis, Paul M.; Liu, H.; Slack, Philip D.; Zorin, Yu.A.; Logatchev, N. A.; Коган, М. Н.; Burkholder, P. D.; Meyer, Robert P.

doi:10.1029/94jb00808

Cited by 84 publications

(84 citation statements)

References 27 publications

(13 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Some seismic studies of upper mantle structure find little evidence for a significant thermal anomaly beneath the rift system and therefore support this view [e.g., ten Brink and Taylor, 2002], while others report slower-than-average upper mantle velocities beneath portions of the rift system, consistent with the presence of thermally modified lithosphere [e.g., Puzyrev et al, 1978;Logatchev and Zorin, 1992;Gao et al, 1994].…”

Section: Introductionmentioning

confidence: 77%

Section: Discussionmentioning

confidence: 99%

“…Gao et al [1994], from inverting P wave travel time residuals, report a $3 % reduction in P wave velocity under the rift over a region some 200-400 km wide, and they attribute this velocity anomaly to small-scale convection beneath the rift. The results of this study are consistent with the model of Gao et al [1994]. The sourcereceiver path for Event 1 crosses the southern margin of the platform, and consequently our results for this event indicate the presence of thermally perturbed upper mantle extending beyond the rift proper.…”

Section: Discussionmentioning

confidence: 99%

“…4, 1153, doi:10.1029/2002GL016115, 2003 Copyright 2003 [Nyblade et al, 1996]. The Q values were taken from Gao et al [1994]. Synthetic PL waveforms were generated using a wavenumber integration method [Kennett, 1983], a 3 s triangular source time function, and the centroid moment tensor (CMT) solution in Table 1.…”

Section: Data and Modelingmentioning

confidence: 99%

See 3 more Smart Citations

Upper mantle P velocity structure beneath the Baikal Rift from modeling regional seismic data

Brazier

Nyblade

2003

Geophysical Research Letters

View full text Add to dashboard Cite

[1] Uppermost mantle P wave velocity structure beneath the Baikal rift and southern margin of the Siberian Platform has been investigated by using a grid search method to model Pnl waveforms from two moderate earthquakes recorded by station TLY at the southwestern end of Lake Baikal. The results yielded a limited number of successful models which indicate the presence of upper mantle P wave velocities beneath the rift axis and the margin of the platform that are 2 -5% lower than expected. The magnitude of the velocity anomalies and their location support the presence of a thermal anomaly that extends laterally beyond the rift proper, possibly created by small-scale convection or a plume-like, thermal upwelling.

show abstract

Section: Introductionmentioning

confidence: 77%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Data and Modelingmentioning

confidence: 99%

See 2 more Smart Citations

Upper mantle P velocity structure beneath the Baikal Rift from modeling regional seismic data

Brazier

Nyblade

2003

Geophysical Research Letters

View full text Add to dashboard Cite

show abstract

“…The analysis of the thermal and therefore rheological outcome of rifting, however, is not straightforward, since opposite trends of thermal evolution may combine. The first issue is that the lithosphere beneath rifts is thinner, whatever the precise mechanism for rifting is (e.g., Achauer and group, 1994;Gao et al, 1994;Granet et al, 1995;Slack et al, 1996).…”

Section: Lithosphere Extension and Riftingmentioning

confidence: 99%

Rheological heterogeneity, mechanical anisotropy and deformation of the continental lithosphere

1998

View full text Add to dashboard Cite

This paper aims to present an overview on the influence of rheological heterogeneity and mechanical anisotropy on the deformation of continents. After briefly recapping the concept of rheological stratification of the lithosphere, we discuss two specific issues: (1) as supported by a growing body of geophysical and geological observations, crust=mantle mechanical coupling is usually efficient, especially beneath major transcurrent faults which probably crosscut the lithosphere and root within the sublithospheric mantle; and (2) in most geodynamic environments, mechanical properties of the mantle govern the tectonic behaviour of the lithosphere. Lateral rheological heterogeneity of the continental lithosphere may result from various sources, with variations in geothermal gradient being the principal one. The oldest domains of continents, the cratonic nuclei, are characterized by a relatively cold, thick, and consequently stiff lithosphere. On the other hand, rifting may also modify the thermal structure of the lithosphere. Depending on the relative stretching of the crust and upper mantle, a stiff or a weak heterogeneity may develop. Observations from rift domains suggest that rifting usually results in a larger thinning of the lithospheric mantle than of the crust, and therefore tends to generate a weak heterogeneity. Numerical models show that during continental collision, the presence of both stiff and weak rheological heterogeneities significantly influences the large-scale deformation of the continental lithosphere. They especially favour the development of lithospheric-scale strike-slip faults, which allow strain to be transferred between the heterogeneities. An heterogeneous strain partition occurs: cratons largely escape deformation, and strain tends to localize within or at the boundary of the rift basins provided compressional deformation starts before the thermal heterogeneity induced by rifting are compensated. Seismic and electrical conductivity anisotropies consistently point towards the existence of a coherent fabric in the lithospheric mantle beneath continental domains. Analysis of naturally deformed peridotites, experimental deformations and numerical simulations suggest that this fabric is developed during orogenic events and subsequently frozen in the lithospheric mantle. Because the mechanical properties of single-crystal olivine are anisotropic, i.e. dependent on the orientation of the applied forces relative to the dominant slip systems, a pervasive fabric frozen in the mantle may induce a significant mechanical anisotropy of the whole lithospheric mantle. It is suggested that this mechanical anisotropy is the source of the so-called tectonic inheritance, i.e. the systematic reactivation of ancient tectonic directions; it may especially explain preferential rift propagation and continental break-up along pre-existing orogenic belts. Thus, the deformation of continents during orogenic events results from a trade-off between tectonic forces applied at plate boundaries, plate geometry,...

show abstract

Characterizing the Present‐Day Activity of the Tunka and Sayan Faults Within Their Relay Zone (Western Baikal Rift System, Russia)

et al. 2018

View full text Add to dashboard Cite

The Sayan and Tunka faults are located at the boundary between the northernmost mountain belt of Central Asia (the Sayan‐Baikal ranges) and the Siberian platform. These prominent crustal structures were involved in the opening of the southern Baikal rift system since the beginning of the Cenozoic and define large‐scale sharp morphotectonic features. Despite low instrumental seismic activity, Late Pleistocene‐Holocene morphotectonic features along the two faults indicate that the faults are active and have the capacity to produce strong earthquakes. A careful mapping of the most recent trace of activity, within the south‐eastern parts of the two faults where they merge within a relay zone, demonstrates that they correspond now to left‐lateral‐reverse faults, suggesting a recent inversion of their vertical component. We also show that the two faults are now structurally connected via a young surface rupture and that no obvious post‐Last Glacial Maximum ruptures are observed along the central part of the Sayan Fault beyond its junction zone with the Tunka fault. This suggests that the left‐lateral strike‐slip deformation is transferred from the eastern Sayan fault to the Tunka fault. A detailed morphotectonic study along the south‐eastern Sayan fault allows estimating a left‐lateral slip rate between 1.3 (min) and 3.9 mm/year (max). Finally, a critical review of Russian paleoseismic data, combined with our paleoseismological investigations, allows us to propose that the mean recurrence time along the two faults is on the order of 4 kyr and that they may have either ruptured together or during seismic clusters.

show abstract

Asymmetric upwarp of the asthenosphere beneath the Baikal rift zone, Siberia

Cited by 84 publications

References 27 publications

Upper mantle P velocity structure beneath the Baikal Rift from modeling regional seismic data

Upper mantle P velocity structure beneath the Baikal Rift from modeling regional seismic data

Rheological heterogeneity, mechanical anisotropy and deformation of the continental lithosphere

Characterizing the Present‐Day Activity of the Tunka and Sayan Faults Within Their Relay Zone (Western Baikal Rift System, Russia)

Contact Info

Product

Resources

About