This study presents new field and petrological data on carbonated metasomatic rocks from the lawsonite-eclogite units of Alpine Corsica. These rocks form along major, slab-scale lithological boundaries of the subducted Alpine Tethys plate. Our results indicate that a large variety of rocks ranging from metamafic/ultramafic to metafelsic can react with carbon-bearing fluids, leading to carbon sequestration at high-pressure conditions. The process of carbonation includes both replacement of silicates by high-pressure carbonate, and carbonate veining. The field, microstructural and mineralogical data strongly suggest that the metasomatism was mediated by the infiltration of external fluids of mixed origin, including both mafic/ultramafic and metasedimentary sources. Our results support the following three-step evolution: (i) Release of aqueous fluids by lawsonite and/or antigorite breakdown at depth; (ii) Fluid channelization along the base of the metasedimentary pile of the subducted lithospheric plate and related reactive fluid flow leading to carbonate mineral dissolution; (iii) Further interactions of the resulting carbon-bearing fluids with slab-forming rocks at depths of ca. 70 km and carbonation of pre-existing silicate-rich lithologies. This study highlights the importance of carbonate-bearing fluids evolving along down-T, down-P paths, such as along slab-parallel lithological boundaries, for the sequestration of carbon in subduction zones, and suggests that similar processes may also operate in collisional settings. © 2018 Elsevier B.V.

Piccoli, F., Vitale Brovarone, A., Ague, J. (2018). Field and petrological study of metasomatism and high-pressure carbonation from lawsonite eclogite-facies terrains, Alpine Corsica. LITHOS, 304-307, 16-37 [10.1016/j.lithos.2018.01.026].

Field and petrological study of metasomatism and high-pressure carbonation from lawsonite eclogite-facies terrains, Alpine Corsica

Vitale Brovarone, A.;
2018

Abstract

This study presents new field and petrological data on carbonated metasomatic rocks from the lawsonite-eclogite units of Alpine Corsica. These rocks form along major, slab-scale lithological boundaries of the subducted Alpine Tethys plate. Our results indicate that a large variety of rocks ranging from metamafic/ultramafic to metafelsic can react with carbon-bearing fluids, leading to carbon sequestration at high-pressure conditions. The process of carbonation includes both replacement of silicates by high-pressure carbonate, and carbonate veining. The field, microstructural and mineralogical data strongly suggest that the metasomatism was mediated by the infiltration of external fluids of mixed origin, including both mafic/ultramafic and metasedimentary sources. Our results support the following three-step evolution: (i) Release of aqueous fluids by lawsonite and/or antigorite breakdown at depth; (ii) Fluid channelization along the base of the metasedimentary pile of the subducted lithospheric plate and related reactive fluid flow leading to carbonate mineral dissolution; (iii) Further interactions of the resulting carbon-bearing fluids with slab-forming rocks at depths of ca. 70 km and carbonation of pre-existing silicate-rich lithologies. This study highlights the importance of carbonate-bearing fluids evolving along down-T, down-P paths, such as along slab-parallel lithological boundaries, for the sequestration of carbon in subduction zones, and suggests that similar processes may also operate in collisional settings. © 2018 Elsevier B.V.
2018
Piccoli, F., Vitale Brovarone, A., Ague, J. (2018). Field and petrological study of metasomatism and high-pressure carbonation from lawsonite eclogite-facies terrains, Alpine Corsica. LITHOS, 304-307, 16-37 [10.1016/j.lithos.2018.01.026].
Piccoli, F.; Vitale Brovarone, A.; Ague, J.J.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/831467
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