http://www.cnr.it/ontology/cnr/individuo/prodotto/ID269271

Shift from lamproite-like to leucititic rocks: Sr-Nd-Pb isotope data from the Monte Cimino volcanic complex vs. the Vico stratovolcano, Central Italy. (Articolo in rivista)

Type

Articolo in rivista (Classe)
Prodotto della ricerca (Classe)

Label

Shift from lamproite-like to leucititic rocks: Sr-Nd-Pb isotope data from the Monte Cimino volcanic complex vs. the Vico stratovolcano, Central Italy. (Articolo in rivista) (literal)

Anno

2013-01-01T00:00:00+01:00 (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi

10.1016/j.chemgeo.2012.10.018 (literal)

Alternative label

Conticelli S. [1, 2], Avanzinelli R. [1], Poli G. [3], Braschi E. [2], Giordano G. [4] (2013)
Shift from lamproite-like to leucititic rocks: Sr-Nd-Pb isotope data from the Monte Cimino volcanic complex vs. the Vico stratovolcano, Central Italy.
in Chemical geology (Online); Elsevier, Amsterdam (Paesi Bassi)
(literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori

Conticelli S. [1, 2], Avanzinelli R. [1], Poli G. [3], Braschi E. [2], Giordano G. [4] (literal)

Pagina inizio

266 (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#url

http://www.journals.elsevier.com/chemical-geology/ (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume

353 (literal)

Rivista

Chemical geology (Rivista)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroFascicolo

246 (literal)

Note

ISI Web of Science (WOS) (literal)
Scopu (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni

[1] Dipartimento di Scienze della Terra, Università degli Studi di Firenze, Firenze, Italy [2] Research Unit of Firenze, Istituto di Geoscienze e Georisorse, C. N. R., Firenze, Italy [3] Dipartimento di Scienze della Terra, Università degli Studi di Perugia, Perugia, Italy [4] Dipartimento di Scienze Geologiche, Università degli Studi di Roma Tre, Roma, Italy (literal)

Titolo

Shift from lamproite-like to leucititic rocks: Sr-Nd-Pb isotope data from the Monte Cimino volcanic complex vs. the Vico stratovolcano, Central Italy. (literal)

Abstract

In the Italian peninsula leucite-free and -bearing ultrapotassic rocks occur intimately associated but well separated in time. Silica-saturated ultrapotassic and associated shoshonitic magmas erupted during the Pliocene to Lower Pleistocene. Silica under-saturated leucite-bearing ultrapotassic rocks, mainly leucitites, were emplaced sometime later, during the Middle-Upper Pleistocene. The transition from leucite-free to -bearing rocks is diachronous and in some cases is complicated by the occurrence of crustal-derived magmas coeval with early leucite-free magma. The Monte Cimino-Vico area is a key locality for studying the transition from leucite-free to -bearing ultrapotassic rocks. There a volcanic complex is overlain by some 500 ka younger leucite-bearing rocks of Vico stratovolcano. Most of the potassic and ultrapotassic rocks of the Monte Cimino volcanic complex are characterised by high Mg-# (66.4-77.8), and compatible element abundances in spite of their high silica contents (52.9-58.0 wt.%). Ultrapotassic leucite-free rocks transitional to lamproites are olivine-bearing orthopyroxene- and plagioclase-free latites and K-rich basaltic trachyandesite and they are confined in the final mafic activity of the Monte Cimino volcanic complex. Two-pyroxene parageneses are observed in the early Monte Cimino volcanic complex giving equilibration temperature as high as 1050 degrees C and suggesting a sub-crustal derivation of their parental magmas. A two-pyroxene high-K calc-alkaline magma is then inferred for the genesis of the early Monte Cimino activity (e.g. dome complex and silicic lava flows and ignimbrites), which was modelled through crystal-fractionation from a high-K basaltic andesitic magma plus mixing with crustal anatectic rhyolitic magma. Final mafic lavas fill the isotopic and chemical gap between shoshonite-like and lamproite-like rocks, and each lava flow could be considered as a mantle-derived term from a heterogeneous sub-continental lithospheric mantle. Final mafic lavas are high-silica and -MgO ultrapotassic rocks due to crystallisation of primitive magmas generated by partial melting of a vein metasomatised network within a lithospheric upper mantle source, at low pressure and high P-H2O. The shift to the younger Vico volcano, in which leucite-bearing magmas prevail, is thought to be due to the arrival in the mantle source of newly formed metasomatic agent from the undergoing slab characterised by the increasing of a sedimentary carbonate recycled component. This new component appears in the Middle Pleistocene and it is responsible for the composition of the magmatism of the Roman region. The recycling of carbonate-bearing pelitic sediments within the mantle wedge produces a carbonate-rich metasomatic agent. The latter is responsible for stabilisation of phlogopite-bearing wehrlitic veins within the mantle wedge. Partial melting of this newly formed vein network under high X-CO2 generated silica undersaturated, and then leucite-bearing, ultrapotassic primary melts. A further shift is observed among the Vico post-caldera magmas, in which the appearance of a deep asthenospheric component is argued to be channelled late through slab-tears. (literal)

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