Perturbing effects of sub-lithospheric mass anomalies in GOCE gravity gradient and other gravity data modelling: Application to the Atlantic-Mediterranean transition zone

Fullea, Javier; Rodríguez‐González, J. A.; Charco, María; Martinec, Z.; Negredo, Ana M.; Villaseñor, Antonio

doi:10.1016/j.jag.2014.02.003

Cited by 30 publications

(29 citation statements)

References 56 publications

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“…This body, already imaged by Blanco and Spakman (1993) and Spakman and Wortel (2004), has been clearly mapped in the new teleseismic tomographic images obtained from the exploitation of the TopoIberia and PICASSO datasets (Bezada et al, 2013, 2014, Bonnin et al, 2014. Those images suggest that the almost vertical slab tears beneath the Eastern Betics, hence providing an explanation of the uplift rates observed in this zone (Garcia-Castellanos and Villaseñor, 2011).…”

Section: Geological and Geophysical Settingmentioning

confidence: 71%

Constraining the crustal root geometry beneath Northern Morocco

et al. 2016

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Section: Geological and Geophysical Settingmentioning

confidence: 71%

Constraining the crustal root geometry beneath Northern Morocco

et al. 2016

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“…At the lithospheric scale other data sets such as SKS splitting [ Diaz and Gallart , ] and surface wave and teleseismic body wave tomography [ Bezada et al ., ; Palomeras et al ., ] also show first order discontinuities below this area. Our results are not consistent with the Moho depth values of 32–36 km previously estimated from heat flow data [ Soto et al ., ] or from combining elevation, geoid, gravity and petrological constrains [ Fullea et al ., ].…”

Section: Discussionmentioning

confidence: 99%

Crustal structure beneath the Rif Cordillera, North Morocco, from the RIFSIS wide‐angle reflection seismic experiment

Gil

Muset

Díaz

et al. 2014

Geochem Geophys Geosyst

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The different geodynamic models proposed since the late 1990s to account for the complex evolution of the Gibraltar Arc System lack definite constraints on the crustal structure of the Rif orogen. Here we present the first well-resolved P-wave velocity crustal models of the Rif Cordillera and its southern continuation toward the Atlas made using controlled-source seismic data. Two 3001 km-long wide-angle reflection profiles crossed the Rif along NS and EW trends. The profiles recorded simultaneously five land explosions of 1Tn each using 850 high frequency seismometers. The crustal structure revealed from 2-D forward modeling delineates a complex, laterally varying crustal structure below the Rif domains. The most surprising feature, seen on both profiles, is a 50 km deep crustal root localized beneath the External Rif. To the east, the crust thins rapidly by 20 km across the Nekkor fault, indicating that the fault is a crustal scale feature. On the NS profile the crust thins more gradually to 40 km thickness beneath Middle Atlas and 42 km beneath the Betics. These new seismic results are in overall agreement with regional trends of Bouguer gravity and are consistent with recent receiver function estimates of crustal thickness. The complex crustal structure of the Rif orogen in the Gibraltar Arc is a consequence of the Miocene collision between the Iberian and African plates. Both the abrupt change in crustal thickness at the Nekkor fault and the unexpectedly deep Rif crustal root can be attributed to interaction of the subducting Alboran slab with the North African passive margin at late Oligocene-early Miocene times.

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“…For instance, using seismic tomography or geodynamic modeling to determine the location and dimension of the mass sources in the mantle, Greff‐Lefftz et al () estimate in a Bayesian framework the corresponding radial density profile and the viscosity profile accounting for dynamic deflections of the internal interfaces that simultaneously explain the amplitude of the geoid, the gravity vector, and the gravity gradients. More locally at upper mantle scales, Fullea et al () constrain the density anomalies using thermal modeling of a subducting slab and test the impact of a continuous or discontinuous sublithospheric slab mass anomaly on the estimated lithospheric structure. On the Moon, Andrews‐Hanna et al () assume a tabular shape of the subsurface mass anomalies causing the observed linear gravity gradient anomalies and exhibit a continuous set of solutions, describing the trade‐offs between the density contrast, the top depth, bottom depth, and lateral extent of the sources, which are then further constrained by adding independent knowledge on acceptable density contrasts or by imposing the bottom depth.…”

Section: Application To Different Types Of Mass Sourcesmentioning

confidence: 99%

An Analysis of Gravitational Gradients in Rotated Frames and Their Relation to Oriented Mass Sources

Panet

2018

JGR Solid Earth

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Many mass sources within the Earth and its fluid envelopes show elongated geometries, aligning with the orientations of plate boundaries and plate motions, coastlines, rivers, and drainage basins for instance. To enhance their identification and separation in global or regional gravity observations and models, a dedicated method based on gravitational gradients analysis is presented here. This approach provides a detailed description of the geographic pattern of the gravity variations, which are accurately mapped thanks to the regular spatial coverage of high‐accuracy satellite data and arise from lateral density changes within the planet. First, gravity gradients are defined at different spatial scales in spherical frames, which are rotated along the radial axis according to the orientation of the source. The sensitivity of these gradients to the mass distribution inside a spherical Earth is described and analytical expressions relating the source to the observable are introduced. Then, the gravity gradients responses at different spatial scales to flat, elementary mass sources located at the surface and at increasing depth are studied. Specifically, the paper investigates how a source width and orientation can be determined, for localized and oscillatory mass anomalies with different width‐to‐length aspect ratios. This theoretical case study aims at providing a basis for the analysis of more complex mass structures, when applying the presented method to static or time‐varying satellite gravity field models. It may help deciphering the nature of the gravity sources by the detection of meaningful geometries and orientations in the gravity field.

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Perturbing effects of sub-lithospheric mass anomalies in GOCE gravity gradient and other gravity data modelling: Application to the Atlantic-Mediterranean transition zone

Cited by 30 publications

References 56 publications

Constraining the crustal root geometry beneath Northern Morocco

Constraining the crustal root geometry beneath Northern Morocco

Crustal structure beneath the Rif Cordillera, North Morocco, from the RIFSIS wide‐angle reflection seismic experiment

An Analysis of Gravitational Gradients in Rotated Frames and Their Relation to Oriented Mass Sources

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