Orogenic, Ophiolitic, and Abyssal Peridotites

Bodinier, Jean-Louis; Godard, Marguerite

doi:10.1016/b978-0-08-095975-7.00204-7

Cited by 189 publications

(173 citation statements)

References 628 publications

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“…These data demonstrate that melt percolation through the extended lithosphere caused a significant heating (from a temperature of c. 1000 8C to c. 1200 8C) by thermal advection, close to asthenospheric conditions (i.e. asthenospherization) up to shallow lithospheric levels (plagioclase peridotite conditions), as previously suggested by Bodinier & Godard (2003), Piccardo (2003) and Müntener et al (2005).…”

Section: Processes Involved In the Passive Rifting Of The Ligurian Tesupporting

confidence: 87%

“…significant heating of the lithosphere to asthenospheric conditions) (e.g. Bodinier & Godard 2003); (2) chemical erosion (i.e. extensive compositional modification, including both element depletion and enrichment), and the formation of depleted spinel harburgites and plagioclase (gabbo-norite)-enriched peridotites (e.g.…”

Section: Processes Involved In the Passive Rifting Of The Ligurian Tementioning

confidence: 99%

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Passive rifting and continental splitting in the Jurassic Ligurian Tethys: the mantle perspective

Piccardo¹

2014

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Based on present knowledge of mantle peridotites from the Ligurian Tethys ophiolites, this paper presents new ideas and a new model for passive rifting to ocean spreading in the slowultraslow rifting Europe-Adria realm. Relevant points include: (i) the positive feedback between deformation and melt percolation during passive magmatic rifting; (ii) the positive feedback between natural evidence and experimental data on the behaviour of the mantle lithosphere during passive rifting; (iii) the significance of hidden magmatism and the associated melt thermal advection; (iv) the role of the wedge-shaped weakened and softened axial zone; and (v) the evidence of a transition from passive to active rifting in the Ligurian Tethys.Passive rifting induced passive asthenospheric upwelling and the onset of partial melting. Fractional melts migrated through the mantle lithosphere and stagnated at shallow levels (the hidden magmatism). Melt thermal advection heated the mantle lithosphere to temperatures (T ) of ≥1200 8C and formed a wedge-shaped axial zone of rheological softened/weakened mantle peridotites that served as the future locus of continental break-up. The hotter/deeper asthenosphere ascended within this axial zone, underwent partial melting and formed aggregated mid-ocean ridge basalts (MORBs) that migrated within dunite channels to form olivine gabbro intrusions and basaltic lava flows. Rifting evolved from passive to active, and the actively upwelling asthenosphere established a ridge-type system and thermal regime.

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Section: Processes Involved In the Passive Rifting Of The Ligurian Tesupporting

confidence: 87%

Section: Processes Involved In the Passive Rifting Of The Ligurian Tementioning

confidence: 99%

Passive rifting and continental splitting in the Jurassic Ligurian Tethys: the mantle perspective

Piccardo¹

2014

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“…The emplacement mechanism of these rocks into the crust remains under discussion (e.g., Bodinier and Godard, 2005;Jagoutz et al, 2006;Labrousse et al, 2011). Many large coherent mantle bodies related to the emplacement of ophiolites (e.g., Oman, Himalaya) are generally thrusted, i.e., obducted, onto the continental crust (e.g., Bard, 1983;Hacker et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Crustal attenuation as a tracer for the emplacement of the Beni Bousera ultramafic massif (Betico-Rifean belt)

Álvarez-Valero

Jagoutz

Stanley

et al. 2014

Geological Society of America Bulletin

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The study of petrology (fi eldwork, petrography, and phase diagram modeling) and structural data of the metapelitic granulites and the southern, high-temperature exposed peridotites in the Beni Bousera massif (northern Morocco), combined with results from previous regional studies of the Alborán, suggest a new emplacement mechanism for the mantle rocks in the Betico-Rifean belt. We document two key metamorphic episodes in the granulites within a temperature window of 710-830 ± 50 °C: (1) An earlier prograde high-pressure period (from 9 ± 1.0 to 12 ± 1.0 kbar) characterized by the assemblage garnet + biotite + kyanite + K-feldspar + rutile. Pressure differences of ~3 kbar are found over a continuous crustal section of ~1.5 km of exposed granulites that indicate a significant crustal attenuation during exhumation of the ultramafi c rocks; and (2) a later postkinematic low-pressure (5 ± 0.8 kbar) symplectic assemblage of cordierite + spinel + plagioclase + sillimanite.At the scale of the entire Betico-Rifean belt, two main contacts are observed as mirror images in both sides of the Alborán Sea:(1) the long axis of the high-temperature ductile contact between granulites and peridotites occurs in the west side of the Beni Bousera and Ronda massifs, coupled with (2) the consistent high-angle, east-dipping normal fault in the east parts of the belt massifs. The integration of the petrologic results with information on the rotation of both contacts reveals ductile deformation in the lower crust related to the emplacement of the ultramafi c rocks in the Betico-Rifean belt along deep-reaching normal faults. The presence of the early hightemperature contact suggests that it was originally a shallow, west-dipping detachment fault developed in a back-arc environment of the east-dipping, retreating subduction zone (current western part of the Gibraltar arc).This scenario is in concordance with the tectonic evolution in western Italy, where anticlockwise Pleistocene rotations associated with northeast-directed thrusting in the Apennines-and coeval with the southeastward motion in the Calabria-Peloritani terrane-were triggered by retreat and rollback of the Adriatic-Ionian slab toward the southeast during the northwest-directed subduction beneath the Calabrian arc.

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“…Melt percolation, thermal advection, lithosphere thermal erosion and asthenospherization of the mantle lithosphere (i.e. Bodinier & Godard 2003;Piccardo 2003;Müntener et al 2005), which characterize the rifting stages of slow -ultraslow spreading oceans (see the discussion in Piccardo et al 2014 and references therein), cause dramatic modifications in the thermal (i.e. rheological) regime of the shallow mantle lithosphere along the axial zone of the extension system before drifting and seafloor spreading: that is, well before 'the installation of a ridge-type thermal regime' (Cannat et al 2009, p. 1;Fig.…”

Section: Conditions Of Thermal Equilibration and Thermal State Of Thementioning

confidence: 99%

Tectonic and magmatic evolution of the mantle lithosphere during the rifting stages of a fossil slow–ultraslow spreading basin: insights from the Erro–Tobbio peridotite (Voltri Massif, NW Italy)

Padovano¹,

Piccardo²,

Vissers

2014

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We investigate the structural, petrological and compositional features recorded by strongly deformed and melt-percolated Erro-Tobbio peridotites (Voltri Massif, Ligurian Alps, NW Italy), in order to demonstrate that the processes of shear-zone formation and melt percolation are intimately linked by a positive feedback. We focus on spinel and plagioclase peridotites, and extensional shear zones that underwent infiltration by upwelling asthenospheric melts. Shear and porosity bands, which developed during extension prior to melt infiltration, represent important structural and rheological pathways to facilitate and enhance melt infiltration into the extending lithosphere and the ascent of such melts to shallower levels.Our results lend strong support to numerical models addressing the physical processes underlying extensional systems. These show that, in the case of slow-ultraslow continental extension and the subsequent formation of slow-ultraslow spreading oceans, porosity and shear-localization bands may develop in a previously unstructured lithosphere, prior to melt infiltration. Our studies on the Erro-Tobbio peridotites allow a model for the inception of continental extension and rifting to drifting of slow-ultraslow spreading oceans to be proposed. We suggest that integrated studies of on-land peridotites, coupled with geophysical -structural results from modern oceans, may provide clues to the geodynamic processes governing continental extension and passive rifting.

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Orogenic, Ophiolitic, and Abyssal Peridotites

Cited by 189 publications

References 628 publications

Passive rifting and continental splitting in the Jurassic Ligurian Tethys: the mantle perspective

Passive rifting and continental splitting in the Jurassic Ligurian Tethys: the mantle perspective

Crustal attenuation as a tracer for the emplacement of the Beni Bousera ultramafic massif (Betico-Rifean belt)

Tectonic and magmatic evolution of the mantle lithosphere during the rifting stages of a fossil slow–ultraslow spreading basin: insights from the Erro–Tobbio peridotite (Voltri Massif, NW Italy)

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