Heat flow and the Eurasian-African plate boundary in the eastern part of the Azores-Gibraltar fracture zone

Verzhbitsky, E. V.; Zolotarev, V.G.

doi:10.1016/0264-3707(89)90009-4

Cited by 13 publications

(10 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Bouguer gravity anomaly also shows a maximum of ∼380 mGal on the Gorringe Bank, and the maximum variation relative to the abyssal plains is ∼120 mGal. We have compiled surface heat flow measurements in the area from different authors (colored circles in Figure 4b) [ Verzhbitsky and Zolotarev , 1989; Polyak et al , 1996; Fernàndez et al , 1998; Rimi et al , 1998; Grevemeyer et al , 2009]. Around the Gorringe Bank there are a few measurements, which vary between 40 and 65 mW/m 2 .…”

Section: Present‐day Lithospheric Structurementioning

confidence: 99%

Lithospheric structure of the Gorringe Bank: Insights into its origin and tectonic evolution

et al. 2010

View full text Add to dashboard Cite

[1] The Gorringe Bank is a 5000 m high seamount near the Atlantic coast of Iberia characterized by a 9 m high geoid anomaly and a ∼120 mGal Bouguer anomaly relative to the surrounding abyssal plains. It has been linked to a NW directed thrust carrying exhumed upper mantle rocks and transitional crust on top of flexeddown Eurasian oceanic crust along the Tagus Abyssal Plain. However, estimations of crustal shortening have yielded dissimilar results, and the deep structure of the ridge remains highly unknown. We present a restored cross section and a new model of the lithospheric structure based on gravity, geoid, elevation, and the presence of serpentinized peridotites. At least 20 km of shortening took place along a flat-ramp-flat thrust fault, and the density structure of the lithosphere is consistent with mantle serpentinization varying from 70% at the surface to 20% at 14 km depth and 0% at 40 km. The topographic relief and gravity anomalies are explained by assuming a flexural isostatic model with an elastic thickness T e of ∼30 km. The evolution of the Gorringe Bank since the Late Jurassic is interpreted in relation to Eurasia-Africa-North America plate motion in four stages: (1) transtension between Newfoundland-Iberia and Africa, which generated small oceanic basins and mantle exhumation; (2) opening of the North Atlantic and seafloor spreading at the NW side of the exhumed Gorringe, which produced gabbro intrusions and serpentinization; (3) a quiescent tectonic period dominated by subsidence and sediment accumulation; and (4) a transpressional plate boundary between Eurasia and Africa with NW directed subcrustal thrusting and generation of the present Gorringe relief. Citation: Jiménez-Munt, I., M. Fernàndez, J. Vergés, J. C. Afonso, D. Garcia-Castellanos, and J. Fullea (2010), Lithospheric structure of the Gorringe Bank: Insights into its origin and tectonic evolution, Tectonics, 29, TC5019,

show abstract

Section: Present‐day Lithospheric Structurementioning

confidence: 99%

Lithospheric structure of the Gorringe Bank: Insights into its origin and tectonic evolution

et al. 2010

View full text Add to dashboard Cite

show abstract

“…Source: TOPEX [ Smith and Sandwell , 1997]. Azores‐Gibraltar Fracture Zone after Verhbitsky and Zolotarev [1989]. Proposed Madeira hotspot track shown as thin dotted line (oldest available radiometric ages for each volcano are given in Ma; see text for details).…”

Section: Introductionmentioning

confidence: 99%

The ⁴⁰Ar/³⁹Ar age dating of the Madeira Archipelago and hotspot track (eastern North Atlantic)

Geldmacher

Bogaard

Hoernle

et al. 2000

Geochem Geophys Geosyst

133

View full text Add to dashboard Cite

The 40Ar/39Ar ages for 35 volcanic rocks and 14C ages for two charcoal samples from the Madeira Archipelago and Ampère Seamount (eastern North Atlantic) are presented. The volcanic evolution of Madeira can be divided into a voluminous shield stage (>4.6–0.7 Ma) and a subsequent low‐volume posterosional stage (<0.7–0 Ma). Volcanism during the shield stage originated from a two‐armed rift system, composed of the E–W oriented Madeira rift arm and the N–S oriented Desertas rift arm. Average growth rates for the submarine (5500 km3/Ma) and subaerial (100–150 km3/Ma) shield stages on Madeira are among the lowest found for ocean island volcanoes. It is proposed that Madeira represents the present location of a >70 Myr old hotspot which formed Porto Santo Island (11.1–14.3 Ma), Seine, Ampère (31 Ma), Corral Patch and Ormond (65–67 Ma [Féraud et al., 1982, 1986]) Seamounts, and the Serra de Monchique (70–72 Ma [McIntyre and Berger, 1982]) complex in southern Portugal. Age and spatial relationships result in a calculated absolute African plate motion above the hotspot of 1.2 cm/yr around a rotation pole located at 43°36′N/ 24°33′W.

show abstract

“…Some correlation between the heat flow in the four cells and the timing of magmatism exists, as well. In western Alps (with the oldest lamproites), the average heat flow is 50-70 mW/m 2 (Della Vedova et al 1991), in the cells with intermediate age lamproites (Betics and Cornacya) the heat flow varies between 70 and 120 mW/m 2 (Verzhbitsky and Zolotarev 1989;Fernandez et al 1998;Della Vedova et al 1991), and in the Tuscany cell with the younger lamproites the heat flow is between 80 and 200 mW/m 2 , with local values above 400 mW/m 2 (Della Vedova et al 1991). Therefore, the sequence of structures reported in Fig.…”

Section: Discussionmentioning

confidence: 98%

The shear-wave velocity structure of the lithosphere–asthenosphere system in the Iberian area and surroundings

Raykova

Panza

2010

Rend. Fis. Acc. Lincei

View full text Add to dashboard Cite

The S-wave velocity model, to the depth of 300 km for the Iberian area and surroundings, is obtained with the non-linear inversion of Rayleigh wave tomographic data in the period range from 5 to 150 s. The three-dimensional model of the region is assembled from 74 juxtaposed one-dimensional cellular structures, sized 1°9 1°, by means of a local smoothing optimisation. The S-wave velocity model shows the almost constant velocity (*4.40 km/s) in the upper mantle beneath the Iberian Massif, the welldeveloped low-velocity zones in the Valencia Trough and under northwest Africa, and specific features of the upper mantle layering in the zone of the Iberian range. The thickness of the crust varies between 25 and 35 km with exceptions in the zones of the Valencia Trough (11-18 km) and Pyrenees (35-45 km). Our Vs models are well correlated with the geological structure along Transmed I and evidence several features of the lithosphere-asthenosphere system in the Betic-Rif domain: quite distinct Iberian, Alboran and Meseta crustal domains; relatively thin, well-developed lithosphere under the Rif system; and clearly defined boundary between the upper and lower asthenosphere. The cellular velocity model of the Betics, where ultrapotassic lamproitic magmatism is observed, has features similar to those of other three areas in the western Mediterranean where ultrapotassic lamproitic magmatism of different age is observed. The crust and upper mantle models in these four areas can be correlated with the age of the magmatism and the local heat flow, and outline how, starting from a naturally quite undifferentiated mantle where magma genesis is currently in progress, the differentiation in lithosphere and asthenosphere can take place in time.

show abstract

Heat flow and the Eurasian-African plate boundary in the eastern part of the Azores-Gibraltar fracture zone

Cited by 13 publications

References 2 publications

Lithospheric structure of the Gorringe Bank: Insights into its origin and tectonic evolution

Lithospheric structure of the Gorringe Bank: Insights into its origin and tectonic evolution

The ⁴⁰Ar/³⁹Ar age dating of the Madeira Archipelago and hotspot track (eastern North Atlantic)

The shear-wave velocity structure of the lithosphere–asthenosphere system in the Iberian area and surroundings

Contact Info

Product

Resources

About

Heat flow and the Eurasian-African plate boundary in the eastern part of the Azores-Gibraltar fracture zone

Cited by 13 publications

References 2 publications

Lithospheric structure of the Gorringe Bank: Insights into its origin and tectonic evolution

Lithospheric structure of the Gorringe Bank: Insights into its origin and tectonic evolution

The 40Ar/39Ar age dating of the Madeira Archipelago and hotspot track (eastern North Atlantic)

The shear-wave velocity structure of the lithosphere–asthenosphere system in the Iberian area and surroundings

Contact Info

Product

Resources

About

The ⁴⁰Ar/³⁹Ar age dating of the Madeira Archipelago and hotspot track (eastern North Atlantic)