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José Correira da Fonseca (Ciclo XXX)

         

 

 

Tutor / Supervisor: prof.ssa Teresa Trua
Co-tutor / Co-supervisor: prof. Andrea Marzoli (Università degli Studi di Padova)

PhD project – Magmatic processes within the plumbing system of the Marsili seamount (Southern Tyrrhenian Sea): constraints from the phenocryst cargo of the sampled lavas

The volcano Marsili, centre of Marsili back-arc basin in southern Tyrrhenian Sea, may be said as the biggest volcano in Europe, elongated 60km NNE-SSW, 20km of maximum width and 3000m of high, with a volume resembling Etna’s. During the last years, it has been a point of great attention for Italy due to the tsunami hazard related with a future eruption and consequent flank collapse, which could affect all the south-western sector of the country. Marsili is also a point of great interest for scientific matters such as geodynamics of subduction-related volcanism and back-arc systems and for magmatic processes. Its super inflated structure may be a consequence lateral boundaries confining the spreading rate of the basin and OIB African mantle input in the IAB magmatic system, increasing magma production and thus vertical accretion of the volcano. The similarity with MOR (mid ocean ridge) features turns Marsili into a “living laboratory” close to the shore, allowing then the comparison with its processes and MOR’s. Former studies identified the mush zone at the depth of the Moho (10km in this basin). Plagioclase and clinopyroxene crystals may show this reservoir as the main fractionation reservoir where also magma mixing processes are documented. Plagioclase Ab-rich crystals point for shallow-crust reservoirs. Only few samples were analysed, limiting the characterisation of these reservoirs. This PhD aims to study and model Marsili’s plumbing system by identifying the main reservoirs and all the differentiation processes occurring there. Ascent rates and residence times will also be estimated to better understand chronologically the system. Phenocrysts (olivine, clinopyroxene and plagioclase) from Marsili’s basalts recovered from all the extent of the seamount will be analysed for major (Electron Microprobe – University of Padova, Italy) and trace elements (LA-ICP-MS – University of Calabria, Italy). Crystals will be analysed for characterization of compositional range of parental magmas, possible chemical disequilibrium profiles or else to provide data for modelling P, T and X conditions during crystallisation. Textures, crystal morphologies and diffusion profiles will be used to model residence times and ascending processes aiming to characterize eruption dynamics. Modelling Marsili’s plumbing system will give further clues on understanding back-arc systems and MOR magmatic structures. 

Presentazioni a congressi e seminari / Conference contributions

  • RiPetERò - Ricerca Petrologica (e non solo) in Emilia Romagna” – Department of Biological, Geological and Environmental Sciences, University of Bologna, Italy, 10/04/2015 (listener).

Corsi e stage / Short courses and stages

  • Short Course “Fluids in the Earth” - Università di Napoli Federico II, Department of Earth, Environmental and Resources Sciences, University of Naples Federico II. Italy. 19-24/10/2015.
  • IVth School of Raman Spectroscopy – Department of Earth Sciences, University of Turin. Italy, 19-21/01/2016.

Other activities

  • Microprobe and SEM-EBSD analysis. Data interpretation and discussions. Collaboration with Dr. Andrea Marzoli and Dr. Richard Spiess. Department of Earth Sciences, University of Padova, Italy. 01/10/2015 until present.
  • LA-ICP-MS analysis and data elaboration. Collaboration with Dr. Donatella Barca. Department of Biology, Ecology and Earth Sciences, University of Calabria, Italy. 01-05/02/2016.
Pubblicato Lunedì, 7 Marzo, 2016 - 18:28 | ultima modifica Giovedì, 10 Marzo, 2016 - 13:08