The lithosphere–asthenosphere boundary in the North-West Atlantic region

Kumar, Prakash; Kind, R.; Hanka, W.; Wylegalla, K.; Reigber, Christoph; Yuan, Xiaohui; Woelbern, I.; Schwintzer, P.; Fleming, Kevin; Dahl‐Jensen, Trine; Larsen, Tine B.; Schweitzer, Johannes; Guðmundsson, Ólafur; Wolf, Detlef

doi:10.1016/j.epsl.2005.05.029

Cited by 133 publications

(119 citation statements)

References 34 publications

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“…The lithosphere-asthenosphere boundary (or equivalently the lithosphere thickness) shown in Figure 14 (middle), has been computed from the 3D S-velocity structure, calculated in the present study and represented by the 2D S-velocity mapping shown in Figure 10, considering for each point of the study area the depth in which the S-velocity starts to decrease with depth. The map of the lithosphere-asthenosphere boundary (LAB), shown in Figure 14 (middle), is a very interesting feature obtained in the present study, which agrees well with that calculated by Kumar et al (2005), from receiver function analysis. The LAB shown in Figure 14 (middle) is more detailed than that calculated by Kumar et al (2005), covering Greenland and its surrounding area more efficiently.…”

Section: Resultssupporting

confidence: 79%

“…The map of the lithosphere-asthenosphere boundary (LAB), shown in Figure 14 (middle), is a very interesting feature obtained in the present study, which agrees well with that calculated by Kumar et al (2005), from receiver function analysis. The LAB shown in Figure 14 (middle) is more detailed than that calculated by Kumar et al (2005), covering Greenland and its surrounding area more efficiently. Also, it should be noted that the lithosphere thickness, for areas in which are present consolidated and old structures, shows values very similar to those calculated for areas with consolidated and old structures in other continents as South America (Corchete, 2012), Antarctica (Corchete, 2013a) or Africa (Corchete, 2013b).…”

Section: Resultssupporting

confidence: 79%

“…They only performed some S-wave velocity profiles (from 50 to 350 km of depth). The lithosphere-asthenosphere boundary (LAB), inferred from these S-velocity profiles agree well with the LAB calculated by Kumar et al (2005), from receiver-function analysis. Finally, Pilidou et al (2005) performed a Rayleigh-wave tomography for the North Atlantic area, in which they obtained S-velocity maps from 75 to 350 km of depth (although the resolution decreases drastically with depth from 200 km).…”

Section: Introductionsupporting

confidence: 64%

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Shear-wave Velocity Structure of Greenland from Rayleigh-wave Analysis

Corchete

2016

Earth sci. res. j.

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The elastic structure beneath Greenland is shown by means of S-velocity maps for depths ranging from zero to 350 km, determined by the regionalization and inversion of Rayleigh-wave dispersion. The traces of 50 earthquakes, occurring from 1990 to 2011, have been used to obtain Rayleigh-wave dispersion data. These earthquakes were registered by 21 seismic station located in Greenland and the surrounding area. The dispersion curves were obtained for periods between 5 and 200 s, by digital filtering with a combination of MFT (Multiple Filter Technique) and TVF (Time Variable Filtering). Later, all seismic events (and some stations) were grouped to obtain a dispersion curve for each source-station path. These dispersion curves were regionalized and inverted according to the generalized inversion theory, to obtain shear-wave velocity models for a rectangular grid of 16x20 points. The shear-velocity structure obtained through this procedure is shown in the S-velocity maps plotted for several depths. These results agree well with the geology and other geophysical results previously obtained. The obtained S-velocity models suggest the existence of lateral and vertical heterogeneity. The zones with consolidated and old structures present greater S-velocity values than the other zones, although this difference can be very little or negligible in some case. Nevertheless, in the depth range of 15 to 45 km, the different Moho depths present in the study area generate the principal variation of S-velocity. A similar behaviour is found for the depth range from 80 to 230 km, in which the lithosphere-asthenosphere boundary (LAB) generates the principal variations of S-velocity. Finally, the new and interesting feature obtained in this study: the definition of the base of the asthenosphere (for the whole study area and for depths ranging from 130 to 280 km, respectively) should be highlighted.La estructura elástica bajo Groenlandia es mostrada por medio de mapas de velocidad de onda para profundidades variando desde cero a 350 km, determinada por la regionalización e inversión de la dispersión de onda Rayleigh. Las trazas de 50 terremotos, ocurridos desde 1990 hasta 2011, han sido usados para obtener datos de dispersión de onda Rayleigh. Estos terremotos fueron registrados por 21 estaciones sísmicas localizadas en Groenlandia y el área circundante. Las curvas de dispersión fueron obtenidas para periodos entre 5 y 200 s, por filtrado digital con una combinación de MFT (Técnica de Filtrado Múltiple) y TVF (Filtrado en Tiempo Variable). Después, todos los eventos sísmicos (y algunas estaciones) fueron agrupados para obtener una curva de dispersión para cada trayecto fuente-estación. Estas curvas de dispersión fueron regionalizadas e invertidas de acuerdo con la teoría de la inversión generalizada, para obtener modelos de velocidad de cizalla para una rejilla rectangular de 16x20 puntos. La estructura de velocidad de cizalla obtenida a través de este procedimiento es mostrada in los mapas de velocidad de onda S representados para var...

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Section: Resultssupporting

confidence: 79%

Section: Resultssupporting

confidence: 79%

Section: Introductionsupporting

confidence: 64%

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Shear-wave Velocity Structure of Greenland from Rayleigh-wave Analysis

Corchete

2016

Earth sci. res. j.

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“…Xenolith suites from both West and East Greenland comprise a mix of depleted harzburgitic lithologies, eclogites, dunites and wehrlites, as well as more 'fertile' lherzolite peridotites. Typically NAC mantle xenoliths encompass both spinel and garnetbearing rocks, corroborating seismic tomographic evidence that these ancient lithospheric keels extend to depths >100 km (Kumar et al, 2005). Research into the mineralogy and isotopic composition of mantle xenoliths from the eastern fragment of the NAC margin in northwest Scotland (UK) has resulted in the identification of several suites of spinel-lherzolite xenoliths (see Upton et al, 2011 and references therein).…”

Section: Introductionmentioning

confidence: 93%

Trace-element abundances in the shallow lithospheric mantle of the North Atlantic Craton margin: Implications for melting and metasomatism beneath Northern Scotland

et al. 2015

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Bulk rock geochemistry and major-and trace-element compositions of clinopyroxene have been determined for three suites of peridotitic mantle xenoliths from the North Atlantic Craton (NAC) in northern Scotland, to establish the magmatic and metasomatic history of subcontinental lithospheric mantle (SCLM) below this region. Spinel lherzolites from the southernmost locality (Streap Com'laidh) have non-NAC mantle compositions, while the two northern xenolith suites (Loch Roag and Rinibar) are derived from the thinned NAC marginal keel. Clinopyroxene compositions have characteristic trace-element signatures which show both 'primary' and 'metasomatic' origins. We use Zr and Hf abundances to identify ancient cryptic refertilization in 'primary' clinopyroxenes. We suggest that Loch Roag and Rinibar peridotite xenoliths represent an ancient ArchaeanPalaeoproterozoic SCLM with original depleted cratonic signatures which were overprinted by metasomatism around the time of intrusion of the Scourie Dyke Swarm (~2.4 Ga). This SCLM keel was preserved during Caledonian orogenesis, although some addition of material and/or metasomatism probably also occurred, as recorded by Rinibar xenoliths. Rinibar and Streap xenoliths were entrained in Permo-Carboniferous magmas and thus were isolated from the SCLM~200 Ma before Loch Roag xenoliths (in an Eocene dyke). Crucially, despite their geographical location, lithospheric mantle peridotite samples from Loch Roag show no evidence of recent melting or refertilization during the Palaeogene opening of the Atlantic.

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“…This method utilizes S-to-P converted waves from the LAB beneath a 3 seismic station. Details of the technique and examples of applications in other regions are given by a number of papers [11][12][13][14][15][16][17][18] . The observed S receiver functions are shown in For verification that a large LAB time corresponds to a thick high-velocity mantle lid, we have looked at the arrival times of the P-to-S converted waves from the 410 discontinuity which roughly sample the average velocity above 410 km depth.…”

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confidence: 99%