Palaeomagnetism and continental collision in the Alpine Belt and the formation of late-tectonic extensional basins

Channell, James E T

doi:10.1144/gsl.sp.1986.019.01.15

Cited by 24 publications

(11 citation statements)

References 91 publications

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“…[1989] reconstruction, assuming that Apulia is attached to Africa plate [Channell, 1986]. We measure $540 km of convergence along the Bb cross section during the last 67 Ma (Figure 2b), well matching, despite the different convergence rates, the estimates by Schmid et al [1996] for the CA (514 km) by retro-deforming crustal cross-sections.…”

Section: Relative Convergence Velocity and Amount Of Subductionsupporting

confidence: 61%

“…One possibility is to estimate the amount of convergence perpendicular to the trench measured from the relative motion of the colliding plates. In Figure 2a we plot the displacement trajectories of Africa and Apulia motion with respect to stable Eurasia during the Tertiary, based on the Dewey et al [1989] reconstruction, assuming that Apulia is attached to Africa plate [ Channell , 1986]. We measure ∼540 km of convergence along the Bb cross section during the last 67 Ma (Figure 2b), well matching, despite the different convergence rates, the estimates by Schmid et al [1996] for the CA (514 km) by retro‐deforming crustal cross‐sections.…”

Section: Relative Convergence Velocity and Amount Of Subductionmentioning

confidence: 99%

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How deep can we find the traces of Alpine subduction?

Piromallo¹,

Faccenna

2004

Geophysical Research Letters

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Slab‐like seismic velocity heterogeneities below the Alpine chain, interpreted as subducted lithosphere, are imaged by tomographic studies down to only about 300 km depth. A non‐negligible discrepancy therefore exists between tomographic and geological data, the latter indicating at least 500 km of Tertiary convergence at trench. Yet a recently published tomographic study detects a pronounced high velocity anomaly at the bottom of the upper mantle right below the Alpine area. Combining tomographic images of the mantle, geological findings and plate system kinematics, we investigate how the presence of this feature in the transition zone below the Alps can be traced back to the Tertiary Alpine subduction and possibly explain the observed discrepancy. We propose that a part of the fast velocity body now residing just above the 660 km discontinuity once belonged to the Alpine slab, torn off by an event occurred at about 30–35 Ma.

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Section: Relative Convergence Velocity and Amount Of Subductionsupporting

confidence: 61%

Section: Relative Convergence Velocity and Amount Of Subductionmentioning

confidence: 99%

How deep can we find the traces of Alpine subduction?

Piromallo¹,

Faccenna

2004

Geophysical Research Letters

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“…7a). The motion of the Adria microplate cannot contribute significantly to increase the convergence because its Tertiary motion can be assumed to be coherent with that of Africa (Channel 1986).…”

Section: African Motion and Trench Orientationmentioning

confidence: 99%

History of subduction and back-arc extension in the Central Mediterranean

Faccenna

Becker

Lucente

et al. 2001

Geophysical Journal International

597

437

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Summary Geological and geophysical constraints to reconstruct the evolution of the Central Mediterranean subduction zone are presented. Geological observations such as upper plate stratigraphy, HP–LT metamorphic assemblages, foredeep/trench stratigraphy, arc volcanism and the back‐arc extension process are used to define the infant stage of the subduction zone and its latest, back‐arc phase. Based on this data set, the time dependence of the amount of subducted material in comparison with the tomographic images of the upper mantle along two cross‐sections from the northern Apennines and from Calabria to the Gulf of Lyon can be derived. Further, the reconstruction is used to unravel the main evolutionary trends of the subduction process. Results of this analysis indicate that (1) subduction in the Central Mediterranean is as old as 80 Myr, (2) the slab descended slowly into the mantle during the first 20–30 Myr (subduction speeds were probably less than 1 cm year− 1), (3) subduction accelerated afterwards, producing arc volcanism and back‐arc extension and (4) the slab reached the 660 km transition zone after 60–70 Myr. This time‐dependent scenario, where a slow initiation is followed by a roughly exponential increase in the subduction speed, can be modelled by equating the viscous dissipation per unit length due to the bending of oceanic lithosphere to the rate of change of potential energy by slab pull. Finally, the third stage is controlled by the interaction between the slab and the 660 km transition zone. In the southern region, this results in an important re‐shaping of the slab and intermittent pulses of back‐arc extension. In the northern region, the decrease in the trench retreat can be explained by the entrance of light continental material at the trench.

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“…The third model considers the release of potential energy, stored in the post-collisional Alpine crustal wedge, to be responsible for the extensional processes. The Tyrrhenian extension could develop rapidly in the previously overthickened suture zone of the Cretaceous-Palaeogene Alpine collision, flanked by a zone of compression (Reutter, Giese & Closs 1980;Horvath & Berckhemer 1982;Channell 1986;Channell & Mareschal 1989). From a mechanical point of view, the collapse of a thickened lithosphere could be favoured by the removal of mantle lithosphere; this process provokes uplift and, in turn, collapse of the lithosphere if support is not provided by the surrounding lithosphere.…”

Section: Introductionmentioning

confidence: 99%

The dynamics of back-arc extension: an experimental approach to the opening of the Tyrrhenian Sea

Faccenna¹,

Davy

Brun

et al. 1996

Geophysical Journal International

234

152

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The E-W-opening Tyrrhenian Sea developed after the Cretaceous-Palaeogene Alpine collision, nearly perpendicular to the motion of the African plate, as a back-arc of the Adria-Ionian westward subduction. Three driving mechanisms have been proposed to explain the dynamic evolution of the Tyrrhenian-Apennine system: ( 1 ) the northward indentation of the African plate; (2) the retreating subduction of the Adria-Ionian lithosphere; and (3) the gravitational collapse of the Alpine post-collisional wedge. In order to define the relative contribution of each of these mechanisms in the Neogene dynamic of the Tyrrhenian-Apennine system, we performed 3-D laboratory experiments, in which we simulated a retreating subduction process in a compressional regime oriented perpendicularly to the direction of subduction; in this framework we also tested the influence of the gravitational collapse of the overriding plate. Experiments were constructed using dry sand and silicone putties to simulate brittle upper crust and ductile lower crust/upper mantle, respectively; these layers floated on a highdensity, low-viscosity glucose syrup which simulated the asthenosphere. The main conclusion of our experiments is that large-scale continental extension, similar to that observed in the Tyrrhenian area, could be reproduced perpendicular to the shortening direction induced by the indentation of the African plate; in this framework, extensional processes are indeed possible if the trench retreat velocity is higher than the rate of shortening induced by the advancing African plate. Our experimental results indicate that this high trench retreat velocity could be explained by the coexistence of the gravitational collapse of the post-Alpine wedge with a slab-pull process, linked to the retreating subduction of the Adria-Ionian plate. While the first mechanism is predominant in the Northern Tyrrhenian area, the second one seems to be important in the latest stage of extension and oceanic accretion of the Southern Tyrrhenian area.

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Palaeomagnetism and continental collision in the Alpine Belt and the formation of late-tectonic extensional basins

Cited by 24 publications

References 91 publications

How deep can we find the traces of Alpine subduction?

How deep can we find the traces of Alpine subduction?

History of subduction and back-arc extension in the Central Mediterranean

The dynamics of back-arc extension: an experimental approach to the opening of the Tyrrhenian Sea

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