Melt-rock reaction and melt migration in the MORB mantle through combined natural and experimental studies

Tipologia
Progetti nazionali
Programma di ricerca
PRIN2015 (Principal Investigator: Elisabetta Rampone, University of Genova)
Ente finanziatore
MIUR
Settore ERC
PE10_10 - Mineralogy, petrology, igneous petrology, metamorphic petrology
PE10_11 - Geochemistry, crystal chemistry, isotope geochemistry, thermodynamics
Periodo
20/09/2016 - 20/09/2019
Responsabile
Prof.ssa Alessandra Montanini

Aree / Gruppi di ricerca

Partecipanti al progetto

Descrizione del progetto

Magma formation at ocean ridges is the primary process that produces the large scale lithologic and chemical heterogeneity of the Earth. Studies on mid-ocean ridge basalts (MORBs) have documented that their mantle sources are chemically and isotopically heterogeneous at all spatial scales. Pyroxenite components in the mantle likely have a key role in the major processes of MORB formation, including polybaric melting, melt segregation from the source region and melt migration through the lithosphere. Because direct sampling of deep mantle is not accessible, however, the origin of pyroxenite heterogeneities is poorly constrained, thereby leaving their strategic role in the generation of oceanic basalts still controversial. This project wishes to integrate field, petrological and geochemical studies on ophiolitic and oceanic mantle sequences with experiments on solids and melts, to explore the heterogeneity of the MORB mantle. Major goal of the project is to improve our knowledge on: (1) the role of pyroxenites in creating chemical and isotopic heterogeneities in the MORB mantle sources, (2) the consequence of a heterogeneous mantle source on the chemistry of MORBs, and (3) the relationships between mantle heterogeneity and channelized melt migration. To address these issues, the project plans to investigate: (i) the origin and geochemical signature of pyroxenites in fertile and depleted oceanic peridotites, which represent the best available proxies of MORB mantle sources and mantle residues after MORB production, (ii) the chemical/isotopic modifications produced by pyroxenite formation in the host peridotite, (iii) the origin of secondary pyroxenites by melt-peridotite reaction, and (iv) the chemical variability of melts migrating through replacive dunites. The selected sample set encompasses: (i) "aged" pyroxenites from fertile mantle sequences of the Alpine-Apennine ophiolites; (ii) pyroxenites from depleted mantle sequences of the Alpine-Apennine ophiolites and modern oceanic setting (Smoothseafloor region, Southwest Indian Ridge); (iii) abyssal peridotites - MORB suites from Vema Lithosperic Section (Mid Atlantic Ridge) and Smoothseafloor region; (iv) replacive dunites from the Alpine-Apennine ophiolites. The origin of secondary pyroxenites will be simulated by melt-rock reaction experiments. A set of high-pressure experiments (1.5-2.5 GPa) will be devoted to define the distribution of trace elements during interaction between peridotite and pyroxenite-derived melts. In addition, partial melting experiments (1200-1400 °C; 1.0-1.5 GPa) on pyroxenite lithologies will shed light on the contribution of these components in the genesis of MORBs. Key information will be provided on the petrologic processes controlling the generation and evolution of lithological-chemical-isotopic heterogeneities along the mantle column, thus improving our knowledge on magmatic processes ruling the chemical differentiation of the Earth's mantle and oceanic crust.

Risultati e pubblicazioni

PUBBLICAZIONI SU RIVISTE:

SECCHIARI, A., MONTANINI, A., BOSCH, D., MACERA, P., CLUZEL, D. (2019) - Sr, Nd, Pb and trace element systematics of the New Caledonia harzburgites: tracking source depletion and contamination processes in a SSZ setting. Geoscience Frontiers, in press

SECCHIARI, A., MONTANINI, A., BOSCH, D., MACERA, P., CLUZEL, D.  (2019) - Origin of the spinel-pyroxene symplectites in the harzburgites from the New Caledonia Peridotite. Ofioliti 44, 31-42

SECCHIARI, A., MONTANINI, A., BOSCH, D., MACERA, P., CLUZEL, D. (2018) The contrasting geochemical message from the New Caledonia gabbronorites: insights on depletion and contamination processes of the sub-arc mantle in a nascent arc setting. Contrib. Mineral.Petrol., in press. DOI: 10.1007/s00410-018-1496-8

SECCHIARI, A., MONTANINI, A., BOSCH, D., MACERA, P., CLUZEL, D. (2016) Melt extraction and enrichment processes in the New Caledonia lherzolites: evidence from geochemical and Sr-Nd isotope data. Lithos 260, 28-43, doi: 10.1016/j.lithos.2016.04.030

COMUNICAZIONI A CONGRESSI

Montanini, A., Secchiari, A., Bosch, D., Macera, P., Cluzel, D. The geochemical message from the New Caledonia gabbronorites: insights on depletion and contamination processes of the sub-arc mantle in a nascent arc setting. New Caledonia Peridotite Amphibious Drilling Workshop 22, 23 and 24th January 2019, Montpellier, France

Secchiari, A., Montanini, A., Bosch, D., Macera, P., Cluzel, D. Geochemical and Sr-Nd-Pb isotope investigation of the New Caledonia peridotite nappe: unravelling the history of a poorly known mantle section. New Caledonia Peridotite Amphibious Drilling Workshop 22, 23 and 24th January 2019, Montpellier, France

Montanini, A., Tribuzio, R., Luguet, A., Van Acken, D. (comunicazione a invito) - From crustal protoliths to mantle pyroxenites: a highly siderophile elements and Os isotope perspective from the External Liguride mantle section (N Apennine, Italy). CONGRESSO SGI-SIMP, Catania 12-14 settembre 2018

Rumbolo, T., Montanini, A., Tribuzio, R., Bosch, D., Bruguier, O. - Are the refractory mantle peridotites from Monte Civrari (W Alps) of subcontinental or abyssal origin? CONGRESSO SGI-SIMP, Catania 12-14 settembre 2018

Van Acken D., Luguet, A., Montanini, A., Tribuzio, R., Daly, J.S. - Pyroxenites as tracers for melt-rock interaction and recycled material in the oceanic mantle. GEOBONN 2018, 2-6 settembre, Bonn (Germania)

Meides, N., Van Acken, D., Luguet, A., Montanini, A., Tribuzio, R. - Sulfide chemistry of pyroxenites from the External Liguride Peridotite Massif, Italy - Implications for melt-rock interactions in the mantle. GEOBONN 2018, 2-6 settembre, Bonn (Germania)

Montanini, A., Tribuzio, R., Van Acken, D., Luguet, A. - An undeformed pyroxenite-peridotite sequence from the External Ligurian ophiolites records multiple events of melt-rock interactions. 3nd EMAW (European Mantle Workshop) Pavia 25-30 giugno 2018.

Rumbolo, T., Montanini, A., Tribuzio, R., Bosch, D. - Chemical and isotopic evolution of mantle peridotites during plagioclase-facies melt-rock interaction (Tuscany ophiolites, Italy). 3nd EMAW (European Mantle Workshop) Pavia 25-30 giugno 2018.

Secchiari, A., Becker, H., Gleißner, P., Li, C., Montanini, A., Bosch, D. - Highly siderophile and chalcophile element behaviour in abyssal-type and supra-subduction zone mantle: constraints from the New Caledonia ophiolite. 3nd EMAW (European Mantle Workshop) Pavia 25-30 giugno 2018.

Secchiari, A., Montanini, A., Bosch, D., Macera, P., Cluzel, D. - Geochemical and Sr-Nd-Pb isotope investigation of the New Caledonia harzburgite: unravelling the evolution of a sub-arc mantle source. 3nd EMAW (European Mantle Workshop) Pavia 25-30 giugno 2018

Secchiari, A., Montanini, A., Bosch, D., Macera, P., Cluzel, D. - Building new crust in a nascent arc setting: the example of the New Caledonia gabbronorites. Geophysical Research Abstracts Vol. 20, EGU General Assembly 2018, Wien

Secchiari, A., Becker, H., Gleißner, P., Li, C., Montanini, A., Bosch, D. - New insights on highly siderophile and chalcophile element behaviour in abyssal-type and supra-subduction zone mantle sections of the New Caledonia ophiolite. Geophysical Research Abstracts Vol. 20, EGU General Assembly 2018, Wien

Rumbolo, T., Montanini, A., Tribuzio, R., Bosch, D. Melt-rock reactions in the mantle peridotites from Tuscany ophiolites. pp.281-281. In CONGRESSO SIMP-SGI-SOGEI-AIV 2017 Abstract Book

Van Acken, D.; Luguet, A.; Montanini, A.; Debaille, V.; Tribuzio, R.; Nowell, G.M.; Daly, G.S. Pyroxenites as carriers of isotopic heterogeneity in the oceanic mantle. In GOLDSCHMIDT CONFERENCE ABSTRACTS, PARIS 2017

FIELD TRIP GUIDEBOOKS

Montanini, A., Tribuzio, R. (2018) - Field trip guidebook “Rifting-related structures in the mantle section from the External Ligurian Ophiolites (Bobbio, Northern Apennine) “, EMAW, European Mantle Workshop, Pavia 25-30 giugno 2018

 

Ultimo aggiornamento: 05/03/2019 08:34
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