Crustal structure from gravity signatures in the Iberian Peninsula

Gómez-Ortíz, David; Agarwal, B. N. P.; Tejero, Rosa; Ruíz, Javier

doi:10.1130/b30224.1

Cited by 28 publications

(22 citation statements)

References 52 publications

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“…We generate the spectral curves for each window by plotting ln (power spectrum) against the wave number ( k ; Figure ). Linear segments and breaks in their slopes characterize the spectral curves, which represent major density discontinuities at different depths (Emishaw et al, ; Fairhead & Okereke, ; Gómez‐Ortiz et al, , ; Leseane et al, ; Sanchez‐Rojas & Palma, ; Tselentis et al, ). Each of the linear segments is associated with a range of wave numbers and provides an indication of their average depth (Gómez‐Ortiz et al, , ).…”

Section: Methodsmentioning

confidence: 99%

“…The lowest wave number segment represents a sharp density contrast between the lithosphere and the asthenosphere, while the intermediate wave number portion corresponds to the sharp density contrast between the crust and mantle, and the highest wave number segment corresponds to shallow causative bodies or noise in the data. We define the depth to the crust‐mantle discontinuity (Moho) as the slope of the intermediate linear segment (Emishaw et al, ; Fairhead & Okereke, ; Gómez‐Ortiz et al, , ; Leseane et al, ; Sanchez‐Rojas & Palma, ; Tselentis et al, ) and the depth to the LAB from the slope of the steepest segment (Figure ) as previously described by Gómez‐Ortiz et al (, ). Gómez‐Ortiz et al () used the spectral analysis to show that the gravity‐derived LAB depth (134 km) beneath the Iberian Peninsula is in agreement with the LAB depth (110–140 km) determined from the modeling of a combination of elevation, gravity, geoid, surface heat flow, and S wave and P wave velocity data by Fullea et al ().…”

Section: Methodsmentioning

confidence: 99%

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Lithospheric Structure of the Malawi Rift: Implications for Magma‐Poor Rifting Processes

et al. 2019

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Our understanding of how magma‐poor rifts accommodate strain remains limited largely due to sparse geophysical observations from these rift systems. To better understand the magma‐poor rifting processes, we investigate the lithospheric structure of the Malawi Rift, a segment of the magma‐poor western branch of the East African Rift System. We analyze Bouguer gravity anomalies from the World Gravity Model 2012 using the two‐dimensional (2‐D) radially averaged power‐density spectrum technique and 2‐D forward modeling to estimate the crustal and lithospheric thickness beneath the rift. We find: (1) relatively thin crust (38–40 km) beneath the northern Malawi Rift segment and relatively thick crust (41–45 km) beneath the central and southern segments; (2) thinner lithosphere beneath the surface expression of the entire rift with the thinnest lithosphere (115–125 km) occurring beneath its northern segment; and (3) an approximately E‐W trending belt of thicker lithosphere (180–210 km) beneath the rift's central segment. We then use the lithospheric structure to constrain three‐dimensional numerical models of lithosphere‐asthenosphere interactions, which indicate ~3‐cm/year asthenospheric upwelling beneath the thinner lithosphere. We interpret that magma‐poor rifting is characterized by coupling of crust‐lithospheric mantle extension beneath the rift's isolated magmatic zones and decoupling in the rift's magma‐poor segments. We propose that coupled extension beneath rift's isolated magmatic zones is assisted by lithospheric weakening due to melts from asthenospheric upwelling whereas decoupled extension beneath rift's magma‐poor segments is assisted by concentration of fluids possibly fed from deeper asthenospheric melt that is yet to breach the surface.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Lithospheric Structure of the Malawi Rift: Implications for Magma‐Poor Rifting Processes

et al. 2019

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“…(See Ayala et al, , for a review.) However, the two margins of the Trough are showing a contrasted crustal thickness passing from 30 to 36 km thick in the Iberia mainland (Gómez‐Ortiz et al, ; Vidal et al, ) to 23–25 km in the Balearic Promontory (Ayala et al, , ; Dañobeitia et al, ; Torne et al, ; Vidal et al, ). The continental crust is thinner in the present‐day Valencia Trough axis where the Moho depth passes from 23–25 km in the SW to 8–12 km in the NE (Ayala et al, , ; Torne et al, ) (Figure ).…”

Section: Geological Settingmentioning

confidence: 99%

Extreme Mesozoic Crustal Thinning in the Eastern Iberia Margin: The Example of the Columbrets Basin (Valencia Trough)

et al. 2018

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Eastern Iberia preserves a complex succession of Mesozoic rifts partly or completely inverted during the Late Cretaceous and Cenozoic in relation with Africa‐Eurasia convergence. Notably, the Valencia Trough, classically viewed as part of the Cenozoic West Mediterranean basins, preserves in its southwestern part a thick Mesozoic succession (locally ≈10 km thick) over a highly thinned continental basement (locally only ≈3.5 km thick). This subbasin, referred to as the Columbrets Basin, represents a Late Jurassic‐Early Cretaceous hyperextended rift basin weakly overprinted by subsequent events. Its initial configuration is well preserved allowing us to unravel its 3‐D architecture and tectonostratigraphic evolution in the frame of the Mesozoic evolution of eastern Iberia. The Columbrets Basin benefits from an extensive data set combining high‐resolution seismic reflection profiles, drill holes, seismic refraction data, and expanding spread profiles. The interactions between halokinesis, involving the Upper Triassic salt, and extensional deformation controlled the architecture of the Mesozoic basin. The thick uppermost Triassic to Cretaceous succession displays a large‐scale “syncline” shape, progressively stretched and dismembered toward the basin borders. We propose that the SE border of the basin is characterized by a large extensional detachment fault acting at crustal scale and interacting locally with the Upper Triassic décollement. This extensional structure accommodates the exhumation of the continental basement and part of the crustal thinning. Eventually, our results highlight the complex interaction between extreme crustal thinning and occurrence of a prerift salt level for the deformation style and tectonostratigraphic evolution of hyperextended rift basins.

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“…The most recent gravimetric compilation, from (Gómez-Ortiz et al, 2011), presents the data as Figure 2 in the paper, which does not have much detail. Neither the database from Gómez-Ortiz et al, 2011 nor the figure in the aforementioned paper is freely available to the public.…”

Section: Introductionmentioning

confidence: 99%

Updated Bouguer anomalies of the Iberian Peninsula: a new perspective to interpret the regional geology

et al. 2016

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Bouguer anomaly maps are powerful cartographic tools used mainly by geoscientists and natural resources' companies (oil, mining, etc.) since they reflect rock density distribution at different depths, allowing the identification of different tectonic features. At upper crustal levels, Bouguer anomaly maps can help, for instance, in characterizing possible ore deposits, ground water reservoirs, petroleum resources, CO 2 storage sites and sedimentary basins; at deeper crustal levels they can help to further refine seismic velocity models or other integrated geophysical models and thus help in deciphering the lateral density variations within the crust and the geometry of the base of the crust. This new Bouguer anomaly map at a 1:1,500,000 scale is based on the compilation of 210,283 gravity stations covering the Iberian Peninsula (c. 583,254 km 2 ). The new map upgrades previous maps in two ways: (1) it is built up from a database with a 15% more spatial coverage than previous compilations and (2) it is freely available. This map show shorter wavelengths than previous published maps thus allowing investigation of smaller geological features. ARTICLE HISTORY

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Crustal structure from gravity signatures in the Iberian Peninsula

Cited by 28 publications

References 52 publications

Lithospheric Structure of the Malawi Rift: Implications for Magma‐Poor Rifting Processes

Lithospheric Structure of the Malawi Rift: Implications for Magma‐Poor Rifting Processes

Extreme Mesozoic Crustal Thinning in the Eastern Iberia Margin: The Example of the Columbrets Basin (Valencia Trough)

Updated Bouguer anomalies of the Iberian Peninsula: a new perspective to interpret the regional geology

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