Asthenospheric diapir beneath the Baikal rift: petrological constraints

Kiselev, A. I.; Popov, Alexander

doi:10.1016/b978-0-444-89912-5.50021-1

Cited by 9 publications

(17 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The timing of Cenozoic uplift is not well constrained [Cunningham, 2001], but it appears that most of the present-day topography dates from the Oligocene to early Miocene [Cunningham, 2001;Cunningham et al, 1996;Baljinnyam et al, 1993]. These features have been cited as evidence for a juvenile mantle plume or asthenospheric diapir that also extends northeastward beneath Lake Baikal [Zorin et al, 1989;Kiselev and Popov, 1992;Windley and Allen, 1993] although others argue against the existence of a plume below the Hangay Dome [Khutorskoy and Yarmoluk, 1989].…”

Section: Hangay Dome -Baikal Rift Regionmentioning

confidence: 99%

Upper mantle structure of eastern Asia from multimode surface waveform tomography

et al. 2006

View full text Add to dashboard Cite

We present a new three-dimensional S-v wave speed and azimuthal anisotropy model for the upper mantle of eastern Asia constrained by the analysis of more than 17,000 vertical component multimode Rayleigh wave seismograms. This data set allows us to build an upper mantle model for Asia with a horizontal resolution of a few hundred kilometers extending to similar to 400 km depth. At 75-100 km depth, there is approximately +/- 9% wave speed perturbation from the "smoothed PREM" reference model used in our analysis, and the pattern of azimuthal anisotropy is complex. Both the amplitude of the Sv wave speed heterogeneity and the complexity and amplitude of the azimuthal anisotropy decrease with depth. Above similar to 200 km depth the upper mantle structure of the model correlates with surface geology and tectonics; below similar to 200 km depth the structures primarily reflect the advection of material in the upper mantle. Since shear wave speed is principally controlled by temperature rather than by composition, Vs(z) can be used to calculate the temperature T(z), and hence map the lithospheric thickness. We use the relationship of Priestley and McKenzie to produce a contour map of the lithospheric thickness of eastern Asia from the surface wave tomography. This shows an extensive region of thick lithosphere beneath the Siberian Platform and the West Siberian Basin that extends to the European Platform, forming the stable Eurasian craton or core. The eastern portion of the Eurasian craton has controlled the geometry of continental deformation and the distribution of kimberlites in eastern Asia

show abstract

Section: Hangay Dome -Baikal Rift Regionmentioning

confidence: 99%

Upper mantle structure of eastern Asia from multimode surface waveform tomography

et al. 2006

View full text Add to dashboard Cite

show abstract

“…Basins within the East Africa rift system, the Ethiopian Rift, the Rio Grande Rift and the Gulf of Suez are arranged along a narrow long axis (the rift valley). The differences between the Baikal rift system and the above rift systems are perhaps related to the location of upper mantle extension and thermal perturbation relative to the location of the crustal rift in light of suggestions for mantle upwelling southeast [Kazmin, 1991;Kiselev and Popov, 1992;Windley and Allen, 1993] or northwest [Petit et al, 1998] of Baikal rift zone. Alternatively, the differences may be attributed to the alignment of the former compression and present extension directions [e.g., Zonenshain et al, 1990], which enables extension by fault reactivation across the width of the fold-and-thrust belt.…”

Section: Deep Seismic Reflection and Refraction Profiles Undermentioning

confidence: 99%

Crustal structure of central Lake Baikal: Insights into intracontinental rifting

Brink

Taylor

2002

J. Geophys. Res.

View full text Add to dashboard Cite

[1] The Cenozoic rift system of Baikal, located in the interior of the largest continental mass on Earth, is thought to represent a potential analog of the early stage of breakup of supercontinents. We present a detailed P wave velocity structure of the crust and sediments beneath the Central Basin, the deepest basin in the Baikal rift system. The structure is characterized by a Moho depth of 39-42.5 km; an 8-km-thick, laterally continuous high-velocity (7.05-7.4 km/s) lower crust, normal upper mantle velocity (8 km/s), a sedimentary section reaching maximum depths of 9 km, and a gradual increase of sediment velocity with depth. We interpret the high-velocity lower crust to be part of the Siberian Platform that was not thinned or altered significantly during rifting. In comparison to published results from the Siberian Platform, Moho under the basin is elevated by <3 km. On the basis of these results we propose that the basin was formed by upper crustal extension, possibly reactivating structures in an ancient fold-and-thrust belt. The extent and location of upper mantle extension are not revealed by our data, and it may be offset from the rift. We believe that the Baikal rift structure is similar in many respects to the Mesozoic Atlantic rift system, the precursor to the formation of the North Atlantic Ocean. We also propose that the Central Baikal rift evolved by episodic fault propagation and basin enlargement, rather than by two-stage rift evolution as is commonly assumed.

show abstract

“…Deep structure of the rift has been long a subject of much debate that largely concentrated around passive versus active rift origin (e.g., Zorin, 1981;Logatchev et al, 1983;Kiselev and Popov, 1992;Gao et al, 1994;Fig. 12.…”

Section: Deep Rift Structure and Time -Space Evolution Of Riftingmentioning

confidence: 99%

Three-dimensional laboratory modelling of rifting: application to the Baikal Rift, Russia

Chemenda¹,

Déverchère²,

Calais³

2002

Tectonophysics

View full text Add to dashboard Cite

Continental rifting is treated as a mechanical instability developing under horizontal tectonic tension. The instability results in strain localization and the formation of a neck, which is interpreted as a rift zone. At the scale of the whole lithospheric plate, this process occurs in plane-stress conditions and can therefore be modelled to a first approximation by a one-layer plate whose properties represent integral (over thickness) properties of the real lithosphere. We have designed a scaled experimental singlelayer lithosphere model having elasto-plastic rheology and lying upon a liquid substratum to study its behaviour under axial horizontal tension. In a homogeneous plate, the instability develops along a linear zone oriented at an angle of f 60j to the tension axis. This orientation is preserved even when the divergent displacement of the plate boundaries is not plain-parallel but rotational. In the latter case, the strain localization zone is rapidly propagating. When the plate length to width ratio is less than f 2.5, the necking develops along two branches conjugated at an angle of about 120j, which is frequently observed in actual rift systems. If the model contains a local weak zone (hot spot or fault zone), the rift junction is located at this zone. In the lithospheric models comprising strong (cratonic) and weak segments, strain localization depends on the configuration of the boundary between different lithospheres. The necking starts to form within the weak segment in the vicinity of the cratonic promontories and propagates in opposite directions again at an angle of ca. 60j to the tension axis. In the models containing both a strong lithosphere and local weak zones, the rift configuration depends on their shape and relative positions, with necking always going through the weak zones. In a set of models, we have reproduced the geometry of the boundary between the Siberian craton and the thermally much younger ( f 100 Ma) Sayan -Baikal lithosphere in the Baikal rift area. In these models, we were able to obtain the well-known three-branch configuration of the Baikal rift system only by introducing a weak zone in the area of Lake Baikal. Such a zone simulates the Paleozoic suture existing in this area. As in nature, two wide outer branches (eastern and western) are oblique to the regional tension axis, whereas the central one is narrow and orthogonal to the tension direction. In nature and in the model, rifting starts in the central branch corresponding to Lake Baikal. The modelling also predicts the formation of a fourth oblique f NS-trending branch to the south of Baikal. Although poorly expressed in the field, this branch has some seismotectonic and magmatic manifestations. The orientations of all four branches with respect to each other and with respect to the regional tension direction are remarkably similar in nature and in the model. D

show abstract

Asthenospheric diapir beneath the Baikal rift: petrological constraints

Cited by 9 publications

References 14 publications

Upper mantle structure of eastern Asia from multimode surface waveform tomography

Upper mantle structure of eastern Asia from multimode surface waveform tomography

Crustal structure of central Lake Baikal: Insights into intracontinental rifting

Three-dimensional laboratory modelling of rifting: application to the Baikal Rift, Russia

Contact Info

Product

Resources

About