Imaging a mantle plume beneath the French Massif Central

Granet, M.; Wilson, Marjorie; Achauer, U.

doi:10.1016/0012-821x(95)00174-b

Cited by 307 publications

(251 citation statements)

References 30 publications

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“…Some of the mentioned volcanic fields were previously studied in more details using temporary seismic networks and based on the teleseismic approach. For example, French Massif Central was studied by Granet et al, (1995). This model was used to estimate the temperature beneath MC (Sobolev et al, 1997).…”

Section: Mantle Structure Beneath Volcanic Fields In Europementioning

confidence: 99%

Multiscale Seismic Tomography Imaging of Volcanic Complexes

Koulakov¹

2012

Updates in Volcanology - A Comprehensive Approach to Volcanological Problems

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Section: Mantle Structure Beneath Volcanic Fields In Europementioning

confidence: 99%

Multiscale Seismic Tomography Imaging of Volcanic Complexes

Koulakov¹

2012

Updates in Volcanology - A Comprehensive Approach to Volcanological Problems

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“…This high-density body coincides with a small highvelocity anomaly at the southern end of the Limagne Graben (Fig. 10a) that was already detected by Granet et al (1995aGranet et al ( , 1995b and Gehrig (2004). The mantle LVA continues downwards into the deepest resolvable model layer (330 km depth, Fig.…”

Section: Modelling Resultssupporting

confidence: 82%

“…They distinguish the region east of the Sillon Houiller fault zone and the region west of it by different anisotropic patterns. In the East they determined the fast polarisation direction φ of the shear-waves to be roughly parallel (φ ≈ N100°E) to the lithospheric lowvelocity zone found by Granet et al (1995b) and related this polarisation direction to magmatic flow during periods of volcanic activity. In the West they detected φ parallel to the Sillon Houiller (φ ≈ N30°E).…”

Section: Introductionmentioning

confidence: 90%

Crustal and Upper Mantle Structure of the French Massif Central Plume

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The Cenozoic volcanism in the French Massif Central region is fed by an upper mantle plume, which was revealed by teleseismic tomography about 10 years ago. This contribution reviews earlier studies and applies a new method to image the crust and upper mantle in the region. Since teleseismic tomography alone has only moderate ability to resolve crustal structures, we perform an integrated study by a joint teleseismic-gravimetric inversion to investigate the gross crustal imprints of the Massif Central. We use a 3-dimensional joint inversion code, which allows a variable model parameterisation, and 3D ray tracing to perform an iterative inversion. Travel time residuals are corrected for Moho topography and sedimentary influences to avoid mapping of known crustal structure into the mantle.Our study finds a prominent low-velocity structure in the upper mantle, which is interpreted as the thermal signature of the Massif Central plume. With a modelled diameter of about 100-120 km it reaches down to at least 330 km depth. The average determined seismic P-wave velocity contrast is -0.6% to -1.0% in the shallow asthenospheric mantle and deeper upper mantle. We found two low-velocity channels in the crustal layer beneath the Cantal/Monte Dore and south of the Devès volcanic fields. A zone of mainly high density and increased seismic velocity is determined in the crust south of the Limagne Graben between the two volcanic fields. Furthermore the Massif Central is characterised by increased seismic scattering in the lithosphere as found by studying the teleseismic P-wave coda. We interpret the detected high-velocity/high-density body and the lithospheric scatterers as cooled magmatic intrusions, produced during the Cenozoic volcanism.

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“…Assuming a geothermal gradient of 13.5 °C kbar -1 (Lucazeau and 200 Bayer, 1982) or 4.2 °C km -1 (Granet et al, 1995), this suggests that they last 201 equilibrated at depths of 55 -65 km, i.e. near to the local lithosphere / asthenosphere 202 boundary (Hirn, 1980).…”

mentioning

confidence: 99%