Shoshonite and sub-alkaline magmas from an ultrapotassic volcano: Sr–Nd–Pb isotope data on the Roccamonfina volcanic rocks, Roman Magmatic Province, Southern Italy.
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| Title: | Shoshonite and sub-alkaline magmas from an ultrapotassic volcano: Sr–Nd–Pb isotope data on the Roccamonfina volcanic rocks, Roman Magmatic Province, Southern Italy. |
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| Authors: | Conticelli, Sandro1,2 sandro.conticelli@unifi.it, Marchionni, Sara1, Rosa, Davide1, Giordano, Guido3, Boari, Elena1, Avanzinelli, Riccardo4 |
| Source: | Contributions to Mineralogy & Petrology. Jan2009, Vol. 157 Issue 1, p41-63. 23p. 3 Charts, 11 Graphs, 1 Map. |
| Subjects: | Mineralogy, Volcanoes, Leucite, Igneous rocks, Roman provinces, Magmas, Lead, Lava, Metasomatism |
| Abstract: | The Roccamonfina volcano is characterised by two stages of volcanic activity that are separated by volcano-tectonic caldera collapses. Ultrapotassic leucite-bearing rocks are confined to the pre-caldera stage and display geochemical characteristics similar to those of other volcanoes in the Roman Province. After the major sector collapse of the volcano, occurred at ca. 400 ka, shoshonitic rocks erupted from cinder cones and domes both within the caldera and on the external flanks of the pre-caldera Roccamonfina volcano. On the basis of new trace element and Sr–Nd–Pb isotope data, we show that the Roccamonfina shoshonitic rocks are distinct from shoshonites of the Northern Roman Province, but are very similar to those of the Neapolitan volcanoes. The last phases of volcanic activity erupted sub-alkaline magmas as enclaves in trachytic domes, and as lavas within the Monte Santa Croce dome. Ultrapotassic rocks of the pre-caldera composite volcano are plagioclase-bearing leucitites characterised by high levels of incompatible trace elements with an orogenic signature having troughs at Ba, Ta, Nb, and Ti, and peaks at Cs, K, Th, U, and Pb. Initial values of 87Sr/86Sr range from 0.70926 to 0.70999, 143Nd/144Nd ranges from 0.51213 to 0.51217, while the lead isotope rations vary between 18.788–18.851 for 206Pb/204Pb, 15.685–15.701 for 207Pb/204Pb, and 39.048–39.076 for 208Pb/204Pb. Shoshonites show a similar pattern of trace element depletions and enrichments to the earlier ultrapotassic leucite-bearing rocks but have a larger degree of differentiation and lower concentrations of incompatible trace elements. On the other hand, shoshonitic rocks have Sr, Nd, and Pb isotopes consistently different than pre-caldera ultrapotassic leucite-bearing rocks. 87Sr/86Sr ranges from 0.70665 to 0.70745, 143Nd/144Nd ranges from 0.51234 to 0.51238, 206Pb/204Pb ranges from 18.924 to 19.153, 207Pb/204Pb ranges from 15.661 to 15.694, and 208Pb/204Pb ranges from 39.084 to 39.212. High-K calc-alkaline samples have intermediate isotopic values between ultrapotassic plagioclase leucitites and shoshonites, but the lowest levels of incompatible trace element contents. It is argued that ultrapotassic magmas were generated in a modified lithospheric mantle after crustal-derived metasomatism. Interaction between the metasomatic agent and lithospheric upper mantle produced a low-melting point metasomatised veined network. The partial melting of the veins alone produced pre-caldera leucite-bearing ultrapotassic magmas. It was possibly triggered by either post-collisional isotherms relaxation or increasing T°C due increasing heat flow through slab tears. Shoshonitic magmas were generated by further melting, at higher temperature, of the same metasomatic assemblage with addition 10–20% of OIB-like astenospheric mantle material. We suggest that addition of astenospheric upper mantle material from foreland mantle, flowing through slab tearing after collision was achieved. [ABSTRACT FROM AUTHOR] |
| Copyright of Contributions to Mineralogy & Petrology is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
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| Items | – Name: Title Label: Title Group: Ti Data: Shoshonite and sub-alkaline magmas from an ultrapotassic volcano: Sr–Nd–Pb isotope data on the Roccamonfina volcanic rocks, Roman Magmatic Province, Southern Italy. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Conticelli%2C+Sandro%22">Conticelli, Sandro</searchLink><relatesTo>1,2</relatesTo><i> sandro.conticelli@unifi.it</i><br /><searchLink fieldCode="AR" term="%22Marchionni%2C+Sara%22">Marchionni, Sara</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Rosa%2C+Davide%22">Rosa, Davide</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Giordano%2C+Guido%22">Giordano, Guido</searchLink><relatesTo>3</relatesTo><br /><searchLink fieldCode="AR" term="%22Boari%2C+Elena%22">Boari, Elena</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Avanzinelli%2C+Riccardo%22">Avanzinelli, Riccardo</searchLink><relatesTo>4</relatesTo> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Contributions+to+Mineralogy+%26+Petrology%22">Contributions to Mineralogy & Petrology</searchLink>. Jan2009, Vol. 157 Issue 1, p41-63. 23p. 3 Charts, 11 Graphs, 1 Map. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Mineralogy%22">Mineralogy</searchLink><br /><searchLink fieldCode="DE" term="%22Volcanoes%22">Volcanoes</searchLink><br /><searchLink fieldCode="DE" term="%22Leucite%22">Leucite</searchLink><br /><searchLink fieldCode="DE" term="%22Igneous+rocks%22">Igneous rocks</searchLink><br /><searchLink fieldCode="DE" term="%22Roman+provinces%22">Roman provinces</searchLink><br /><searchLink fieldCode="DE" term="%22Magmas%22">Magmas</searchLink><br /><searchLink fieldCode="DE" term="%22Lead%22">Lead</searchLink><br /><searchLink fieldCode="DE" term="%22Lava%22">Lava</searchLink><br /><searchLink fieldCode="DE" term="%22Metasomatism%22">Metasomatism</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: The Roccamonfina volcano is characterised by two stages of volcanic activity that are separated by volcano-tectonic caldera collapses. Ultrapotassic leucite-bearing rocks are confined to the pre-caldera stage and display geochemical characteristics similar to those of other volcanoes in the Roman Province. After the major sector collapse of the volcano, occurred at ca. 400 ka, shoshonitic rocks erupted from cinder cones and domes both within the caldera and on the external flanks of the pre-caldera Roccamonfina volcano. On the basis of new trace element and Sr–Nd–Pb isotope data, we show that the Roccamonfina shoshonitic rocks are distinct from shoshonites of the Northern Roman Province, but are very similar to those of the Neapolitan volcanoes. The last phases of volcanic activity erupted sub-alkaline magmas as enclaves in trachytic domes, and as lavas within the Monte Santa Croce dome. Ultrapotassic rocks of the pre-caldera composite volcano are plagioclase-bearing leucitites characterised by high levels of incompatible trace elements with an orogenic signature having troughs at Ba, Ta, Nb, and Ti, and peaks at Cs, K, Th, U, and Pb. Initial values of 87Sr/86Sr range from 0.70926 to 0.70999, 143Nd/144Nd ranges from 0.51213 to 0.51217, while the lead isotope rations vary between 18.788–18.851 for 206Pb/204Pb, 15.685–15.701 for 207Pb/204Pb, and 39.048–39.076 for 208Pb/204Pb. Shoshonites show a similar pattern of trace element depletions and enrichments to the earlier ultrapotassic leucite-bearing rocks but have a larger degree of differentiation and lower concentrations of incompatible trace elements. On the other hand, shoshonitic rocks have Sr, Nd, and Pb isotopes consistently different than pre-caldera ultrapotassic leucite-bearing rocks. 87Sr/86Sr ranges from 0.70665 to 0.70745, 143Nd/144Nd ranges from 0.51234 to 0.51238, 206Pb/204Pb ranges from 18.924 to 19.153, 207Pb/204Pb ranges from 15.661 to 15.694, and 208Pb/204Pb ranges from 39.084 to 39.212. High-K calc-alkaline samples have intermediate isotopic values between ultrapotassic plagioclase leucitites and shoshonites, but the lowest levels of incompatible trace element contents. It is argued that ultrapotassic magmas were generated in a modified lithospheric mantle after crustal-derived metasomatism. Interaction between the metasomatic agent and lithospheric upper mantle produced a low-melting point metasomatised veined network. The partial melting of the veins alone produced pre-caldera leucite-bearing ultrapotassic magmas. It was possibly triggered by either post-collisional isotherms relaxation or increasing T°C due increasing heat flow through slab tears. Shoshonitic magmas were generated by further melting, at higher temperature, of the same metasomatic assemblage with addition 10–20% of OIB-like astenospheric mantle material. We suggest that addition of astenospheric upper mantle material from foreland mantle, flowing through slab tearing after collision was achieved. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Contributions to Mineralogy & Petrology is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1007/s00410-008-0319-8 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 23 StartPage: 41 Subjects: – SubjectFull: Mineralogy Type: general – SubjectFull: Volcanoes Type: general – SubjectFull: Leucite Type: general – SubjectFull: Igneous rocks Type: general – SubjectFull: Roman provinces Type: general – SubjectFull: Magmas Type: general – SubjectFull: Lead Type: general – SubjectFull: Lava Type: general – SubjectFull: Metasomatism Type: general Titles: – TitleFull: Shoshonite and sub-alkaline magmas from an ultrapotassic volcano: Sr–Nd–Pb isotope data on the Roccamonfina volcanic rocks, Roman Magmatic Province, Southern Italy. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Conticelli, Sandro – PersonEntity: Name: NameFull: Marchionni, Sara – PersonEntity: Name: NameFull: Rosa, Davide – PersonEntity: Name: NameFull: Giordano, Guido – PersonEntity: Name: NameFull: Boari, Elena – PersonEntity: Name: NameFull: Avanzinelli, Riccardo IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 01 Text: Jan2009 Type: published Y: 2009 Identifiers: – Type: issn-print Value: 00107999 Numbering: – Type: volume Value: 157 – Type: issue Value: 1 Titles: – TitleFull: Contributions to Mineralogy & Petrology Type: main |
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