The ligurian ophiolites constitute an accessible and unique window to track the opening and evolution of slowspreading oceanic lithosphere. The internal ligurian ophiolites consist of km-scale gabbroic bodies intruded into depleted mantle peridotites and bear remarkable structural and compositional similarities to oceanic lithosphere from slow and ultra-slow spreading ridges. The external ligurian ophiolites are associated with continental crust material and include mantle sequences retaining a subcontinental lithospheric origin. This field trip explores two gabbro-peridotite associations from the internal ligurian ophiolites: i) the Bracco- Levanto ophiolite, which includes a km-scale gabbroic body recalling the oceanic core complexes from modern spreading centres (e.g. the Atlantis Massif, Atlantic Ocean); ii) the Scogna-Rocchetta Vara ophiolite, which lacks the basalt layer similar to the nonvolcanic sections from Atlantic and Indian oceans. The peridotites and the gabbros from both these ophiolites record a composite history involving deformation and alteration from high temperature to seafloor conditions. The field excursion also explores peridotite bodies from the external ligurian ophiolites, representing a nice example of MORB-type pyroxenite-bearing mantle.

The Ligurian Ophiolites: a journey through the building and evolution of slow spreading oceanic lithosphere

BORGHINI, GIULIO;RAMPONE, ELISABETTA;
2014-01-01

Abstract

The ligurian ophiolites constitute an accessible and unique window to track the opening and evolution of slowspreading oceanic lithosphere. The internal ligurian ophiolites consist of km-scale gabbroic bodies intruded into depleted mantle peridotites and bear remarkable structural and compositional similarities to oceanic lithosphere from slow and ultra-slow spreading ridges. The external ligurian ophiolites are associated with continental crust material and include mantle sequences retaining a subcontinental lithospheric origin. This field trip explores two gabbro-peridotite associations from the internal ligurian ophiolites: i) the Bracco- Levanto ophiolite, which includes a km-scale gabbroic body recalling the oceanic core complexes from modern spreading centres (e.g. the Atlantis Massif, Atlantic Ocean); ii) the Scogna-Rocchetta Vara ophiolite, which lacks the basalt layer similar to the nonvolcanic sections from Atlantic and Indian oceans. The peridotites and the gabbros from both these ophiolites record a composite history involving deformation and alteration from high temperature to seafloor conditions. The field excursion also explores peridotite bodies from the external ligurian ophiolites, representing a nice example of MORB-type pyroxenite-bearing mantle.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11567/760990
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