Gravity-inferred crustal thickness of Greenland

Braun, Alexander; Kim, Hyung Rae; Csathó, Beáta; Frese, Ralph R. B. von

doi:10.1016/j.epsl.2007.07.050

Cited by 40 publications

(68 citation statements)

References 56 publications

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“…Thus, if the S-velocity value of 4 km/s is used to find the Moho depth in the whole study area, considering that an S-velocity value greater than 4 km/s is associated with upper-mantle structure, then it is possible to plot a map of the Moho discontinuity, such as the map shown in Figure 14 (top), from the S-velocity mapping shown in Figure 10 (which is in fact an ensemble of 2D plots for a 3D S-velocity distribution). The Moho map shown in Figure 14 (top) agrees well with the Moho map calculated by Braun et al (2007), for Greenland and its surrounding area. Also, a good agreement is found with the Moho depths calculated by Dahl-Jensen et al (2003), from receiver-function analysis.…”

Section: Resultssupporting

confidence: 77%

“…Logically, the information about the Greenland structure that can be discerned from global mappings will have always a poor resolution. On the other hand, the S-velocities shown in Figure 9a present high values in general, as expected for the block area shown in Figure 8, which is inside of an Archean block that hosts some of the oldest rocks on Earth and therefore has a high rigidity (Braun et al, 2007). Shear velocity mapping.…”

Section: Inversion Of Regionalized Dispersion Curvessupporting

confidence: 70%

“…Later, Dahl-Jensen et al (2003) provided information about the Moho depth, in many locations in Greenland, calculated from receiver-function analysis. These depths have later been confirmed by other authors as Braun et al (2007), but they didn't perform any surface-wave tomography. The first attempt of tomography for Greenland was performed by Darbyshire et al (2004), who investigated the crust and upper mantle structure using surfacewave tomography by first time.…”

Section: Introductionmentioning

confidence: 56%

“…This information has been incorporated to the initial models, for the above-mentioned grid points (or blocks). Particularly, the Moho depths calculated by Dahl-Jensen et al (2003), for many places in Greenland, has been used to provide the Moho depth in the initial models, as well as the Moho depths predicted by the Moho map performed by Braun et al (2007). Thus, an initial model has been prepared for each grid point (or block) for depths ranging from 0 to 400 km.…”

Section: ̅ = Baxmentioning

confidence: 99%

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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: 77%

Section: Inversion Of Regionalized Dispersion Curvessupporting

confidence: 70%

Section: Introductionmentioning

confidence: 56%

Section: ̅ = Baxmentioning

confidence: 99%

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

Corchete

2016

Earth sci. res. j.

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“…Gravimetric methods have also been extensively used in regional studies, where more detailed additional constraining geoscientific information is available and where integrated simultaneous modelling of several geophysical fields is often applied. For more details, we refer readers to studies by Bielik (1988), , , Yegorova et al (1998), Kaban (2001Kaban ( , 2002, Zeyen et al (2002), Perry et al (2003, Bielik et al (2004), Dérerová et al (2006), Braun et al (2007), Tesauro et al (2007), Alvey et al (2008), Jiménez-Munt et al (2008, Maystrenko and Scheck-Wenderoth (2009), Mooney and Kaban (2010) and references therein.…”

Section: Introductionmentioning

confidence: 99%

Spatial and Spectral Analysis of Refined Gravity Data for Modelling the Crust–Mantle Interface and Mantle-Lithosphere Structure

et al. 2012

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We analyse spatial and spectral characteristics of various refined gravity data used for modelling and gravimetric interpretation of the crust-mantle interface and the mantle-lithosphere structure. Depending on the purpose of the study, refined gravity data have either a strong or weak correlation with the Moho depths (Moho geometry). The compilation of the refined gravity data is purely based on available information on the crustal density structure obtained from seismic surveys without adopting any isostatic hypothesis. We demonstrate that the crust-stripped relative-to-mantle gravity data have a weak correlation with the CRUST2.0 Moho depths of about 0.02. Since gravitational signals due to the crustal density structure and the Moho geometry are subtracted from gravity field, these refined gravity data comprise mainly the information on the mantle lithosphere and sub-lithospheric mantle. On the other hand, the consolidated crust-stripped gravity data, obtained from the gravity field after applying the crust density contrast stripping corrections, comprise mainly the gravitational signal of the Moho geometry, although they also contain the gravitational signal due to anomalous mass density structures within the mantle. In the absence of global models of the mantle structure, the best possible option of computing refined gravity data, suitable for the recovery/refinement of the Moho interface, is to subtract the complete crust-corrected gravity data from the consolidated crust-stripped gravity data. These refined gravity data, that is, the homogenous crust gravity data, have a strong absolute correlation of about 0.99 with the CRUST2.0 Moho depths due to removing a gravitational signal of inhomogeneous density structures within the crust and mantle. Results of the spectral signal decomposition and the R. Tenzer (&) Á V. Gladkikh subsequent correlation analysis reveal that the correlation of the homogenous crust gravity data with the Moho depths is larger than 0.9 over the investigated harmonic spectrum up to harmonic degree 90. The crust-stripped relative-to-mantle gravity data correlate substantially with the Moho depths above harmonic degree 50 where the correlation exceeds 0.5.

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A crustal model for northern Melville Bay, Baffin Bay

et al. 2014

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The interpretation of seismic refraction and gravity data acquired in 2010 gives new insights into the crustal structure of the West Greenland coast and the adjacent deep central Baffin Bay basin. Underneath Melville Bay, the depth of the Moho varies between 26 and 17 km. Stretched continental crust with a thickness of 25 to 14 km and deep sedimentary basins are present in this area. The deep Melville Bay Graben contains an up to~11 km thick infill of consolidated and unconsolidated sediments with velocities of 1.6 to 4.9 km/s. Seaward, at the~60 km wide transition between oceanic and stretched continental crust, a mount-shaped magmatic structure is observed, which most likely formed prior to the initial formation of oceanic crust. The up to 4 km high magmatic structure is underlain by a~2 km thick and~50 km wide high velocity lower crust. More to the west, in the oceanic part of the Baffin Bay basin, we identify a two-layered, 3.5 to 6 km thin igneous oceanic crust with increasing thickness toward the shelf. Beneath the oceanic crust, the depth of the Moho ranges between 11.5 and 13.5 km. In the western part of the profile, oceanic layer 3 is unusually thin (~1.5 km) A possible explanation for the thin crust is accretion due to slow spreading, although the basement is notably smooth compared to the basement of other regions formed by ultra-slow spreading. The oceanic crust is underlain by partly serpentinized upper mantle with velocities of 7.6 to 7.8 km/s.

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Gravity-inferred crustal thickness of Greenland

Cited by 40 publications

References 56 publications

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

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

Spatial and Spectral Analysis of Refined Gravity Data for Modelling the Crust–Mantle Interface and Mantle-Lithosphere Structure

A crustal model for northern Melville Bay, Baffin Bay

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