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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)

Matteo Padovano, Giovanni B. Piccardo and Reinoud L. M. Vissers
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) (in Sedimentary basins and crustal processes at continental margins; from modern hyper-extended margins to deformed ancient analogues, G. M. Gibson (editor), F. Roure (editor) and G. Manatschal (editor))
Special Publication - Geological Society of London (December 2014) 413 (1): 205-238

Abstract

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.


ISSN: 0305-8719
EISSN: 2041-4927
Coden: GSLSBW
Serial Title: Special Publication - Geological Society of London
Serial Volume: 413
Serial Issue: 1
Title: 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)
Title: Sedimentary basins and crustal processes at continental margins; from modern hyper-extended margins to deformed ancient analogues
Author(s): Padovano, MatteoPiccardo, Giovanni B.Vissers, Reinoud L. M.
Author(s): Gibson, G. M.editor
Author(s): Roure, F.editor
Author(s): Manatschal, G.editor
Affiliation: Consultant, Genoa, Italy
Pages: 205-238
Published: 20141203
Text Language: English
Publisher: Geological Society of London, London, United Kingdom
Number of pages: 34
References: 108
Accession Number: 2015-021559
Categories: Structural geologyIgneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 6 tables, geol. sketch maps
N44°31'60" - N44°32'60", E08°46'60" - E08°49'00"
Secondary Affiliation: Utrecht University, NLD, Netherlands
Source Note: Online First
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from The Geological Society, London, London, United Kingdom
Update Code: 201511
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