Continental vs. oceanic lithosphere beneath the eastern Mediterranean Sea — Implications from Rayleigh wave dispersion measurements

Erduran, Murat; Endrun, B.; Meier, Thomas

doi:10.1016/j.tecto.2008.05.015

Cited by 22 publications

(14 citation statements)

References 73 publications

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“…Previous local surface wave studies have been limited by relatively sparse or uneven station coverage. These studies highlight the existence of strong differences in mantle shear velocities in different parts of our study area (Bourova et al 2005; Karagianni et al 2005; Endrun et al 2008; Erduran et al 2008).…”

Section: Introductionmentioning

confidence: 55%

High-resolution surface wave tomography beneath the Aegean-Anatolia region: constraints on upper-mantle structure

Salaün¹,

Pedersen²,

Ambert³

et al. 2012

Geophysical Journal International

108

115

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SUMMARY This study provides new constraints on the upper‐mantle structure from western Greece to central Anatolia using seismic data of permanent broad‐band networks recently installed in Greece and Turkey and from a two‐year temporary array (SIMBAAD experiment). We used ∼200 seismic events recorded at 146 broad‐band stations with a typical interstation distance of 60–100 km across the study area. The high‐resolution 3‐D shear wave velocity model of the mantle is obtained by inversion of fundamental‐mode Rayleigh wave phase velocity maps for periods between 20 and 195 s. The tomography is based on ray tracing in heterogeneous media taking into account external propagation effects. The horizontal resolution is approximately 100 km, however small heterogeneities may suffer from some horizontal smearing and damping. The vertical resolution is approximately 100 km. The vertical smoothing is necessary to avoid unresolved spurious shear wave velocity oscillations in the upper mantle. The errors on shear wave velocities in our 3‐D model (0.02–0.1 km s−1) are significantly smaller than the amplitude of Vs variations (0.3–0.5 km s−1). In spite of the vertical and horizontal smoothing, our model shows details in the upper‐mantle structure never reached at regional scale in the area. The overall structure is characterized by a low‐velocity zone (80–200 km depth) reflecting a slow and warm asthenosphere underlying a thin lithosphere. The southwesternmost termination of the low‐velocity anomaly corresponds to the northward dipping Hellenic slab. The detailed shear velocity structure of the upper mantle beneath Anatolia appears to be far more geometrically complex than revealed in previous tomographic studies of the area. At depths larger than or equal to 160 km, velocities are overall high beneath Anatolia, partly due to the presence of dipping high‐velocity anomalies which we tentatively interpret as remnant slabs. The southernmost high‐velocity anomaly beneath Anatolia is separated from the eastern edge of the Hellenic slab by a major low‐velocity anomaly which we interpret as the trace of asthenospheric mantle material rising inside a vertical slab tear beneath southwestern Anatolia.

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Section: Introductionmentioning

confidence: 55%

High-resolution surface wave tomography beneath the Aegean-Anatolia region: constraints on upper-mantle structure

Salaün¹,

Pedersen²,

Ambert³

et al. 2012

Geophysical Journal International

108

115

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“…16). The DSTF is located above a shallow asthenosphere, characterized by very low S velocities (Debayle et al 2001; Sebai et al 2006; Pasyanos & Nyblade 2007; Erduran et al 2008; Chang & van der Lee 2011).…”

Section: Discussion Of the 3‐d Upper‐mantle S‐wave Modelsmentioning

confidence: 99%

A shear wave velocity model of the European upper mantle from automated inversion of seismic shear and surface waveforms

Legendre¹,

Meier²,

Lebedev³

et al. 2012

Geophysical Journal International

106

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SUMMARY We present a new, S‐velocity model of the European upper mantle, constrained by inversions of seismic waveforms from broad‐band stations in Europe and surrounding regions. We collected seismograms for the years 1990–2007 from all permanent stations in Europe for which data were available. In addition, we incorporated data from temporary experiments. Automated multimode inversion of surface and S‐wave forms was applied to extract structural information from the seismograms, in the form of linear equations with uncorrelated uncertainties. The equations were then solved for seismic velocity perturbations in the crust and mantle with respect to a 3‐D reference model with a realistic crust. We present two versions of the model: one for the entire European upper mantle and another, with the highest resolution, focused on the upper 200 km of the mantle beneath western and central Europe and the circum Mediterranean. The mantle lithosphere and asthenosphere are well resolved by both models. Major features of the lithosphere–asthenosphere system in Europe and the Mediterranean are indentified. The highest velocities in the mantle lithosphere of the East European Craton (EEC) are found at about 150 km depth. There are no indications for a deep cratonic root below about 330 km depth. Lateral variations within the cratonic mantle lithosphere are resolved as well. The locations of kimberlites correlate with reduced S‐wave velocities in the shallow cratonic mantle lithosphere. This anomaly is present in regions of both Proterozoic and Archean crust, pointing to an alteration of the mantle lithosphere after the formation of the craton. Strong lateral changes in S‐wave velocity are found at the northwestern margin of the EEC and may indicate erosion of cratonic mantle lithosphere beneath the Scandes by hot asthenosphere. The mantle lithosphere beneath western Europe and between the Tornquist–Teisseyre Zone and the Elbe Line shows moderately high velocities and is of an intermediate character, between cratonic lithosphere and the thin lithosphere of central Europe. In central Europe, Caledonian and Variscian sutures are not associated with strong lateral changes in the lithosphere–asthenosphere system. Cenozoic anorogenic intraplate volcanism in central Europe and the circum Mediterranean is found in regions of shallow asthenosphere and close to changes in the depth of the lithosphere–asthenosphere boundary. Very low velocities at shallow upper‐mantle depths are present from eastern Turkey towards the Dead Sea transform fault system and Sinai, beneath locations of recent volcanism. Low‐velocity anomalies extending vertically from shallow upper mantle down to the transition zone are found beneath the Massif Central, Sinai and the Dead Sea, the Canary Islands and Iceland.

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“…The stacking strategy for the extraction of a reference phase‐velocity dispersion curve is somewhat similar to that applied to ambient‐noise data by Rawlinson et al (). The maximum values of the distribution at each period have been used to extract a dispersion curve that was inverted using a nonlinear Levenberg‐Marquardt gradient search algorithm (e.g., Agius & Lebedev, ; Erduran et al, ; Lebedev et al, ; Meier et al, ) for a

V_{normalS}

profile. The synthetic phase‐velocity curve computed for this profile (green line in Figure ) represents an accurate regional reference model.…”

Section: Data and Measurementsmentioning

confidence: 99%

Hot Upper Mantle Beneath the Tristan da Cunha Hotspot From Probabilistic Rayleigh‐Wave Inversion and Petrological Modeling

Bonadio

Geissler

Lebedev

et al. 2018

Geochem Geophys Geosyst

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Understanding the enigmatic intraplate volcanism in the Tristan da Cunha region requires knowledge of the temperature of the lithosphere and asthenosphere beneath it. We measured phase‐velocity curves of Rayleigh waves using cross‐correlation of teleseismic seismograms from an array of ocean‐bottom seismometers around Tristan, constrained a region‐average, shear‐velocity structure, and inferred the temperature of the lithosphere and asthenosphere beneath the hotspot. The ocean‐bottom data set presented some challenges, which required data‐processing and measurement approaches different from those tuned for land‐based arrays of stations. Having derived a robust, phase‐velocity curve for the Tristan area, we inverted it for a shear wave velocity profile using a probabilistic (Markov chain Monte Carlo) approach. The model shows a pronounced low‐velocity anomaly from 70 to at least 120 km depth. VnormalS in the low velocity zone is 4.1–4.2 km/s, not as low as reported for Hawaii (∼4.0 km/s), which probably indicates a less pronounced thermal anomaly and, possibly, less partial melting. Petrological modeling shows that the seismic and bathymetry data are consistent with a moderately hot mantle (mantle potential temperature of 1,410–1,430°C, an excess of about 50–120°C compared to the global average) and a melt fraction smaller than 1%. Both purely seismic inversions and petrological modeling indicate a lithospheric thickness of 65–70 km, consistent with recent estimates from receiver functions. The presence of warmer‐than‐average asthenosphere beneath Tristan is consistent with a hot upwelling (plume) from the deep mantle. However, the excess temperature we determine is smaller than that reported for some other major hotspots, in particular Hawaii.

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Continental vs. oceanic lithosphere beneath the eastern Mediterranean Sea — Implications from Rayleigh wave dispersion measurements

Cited by 22 publications

References 73 publications

High-resolution surface wave tomography beneath the Aegean-Anatolia region: constraints on upper-mantle structure

High-resolution surface wave tomography beneath the Aegean-Anatolia region: constraints on upper-mantle structure

A shear wave velocity model of the European upper mantle from automated inversion of seismic shear and surface waveforms

Hot Upper Mantle Beneath the Tristan da Cunha Hotspot From Probabilistic Rayleigh‐Wave Inversion and Petrological Modeling

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