Journal Title
Title of Journal: Contrib Mineral Petrol
|
Abbravation: Contributions to Mineralogy and Petrology
|
Publisher
Springer-Verlag
|
|
|
|
|
|
Authors: Sandro Conticelli Sara Marchionni Davide Rosa Guido Giordano Elena Boari Riccardo Avanzinelli
Publish Date: 2008/06/27
Volume: 157, Issue: 1, Pages: 41-63
Abstract
The Roccamonfina volcano is characterised by two stages of volcanic activity that are separated by volcanotectonic caldera collapses Ultrapotassic leucitebearing rocks are confined to the precaldera 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 precaldera 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 subalkaline magmas as enclaves in trachytic domes and as lavas within the Monte Santa Croce dome Ultrapotassic rocks of the precaldera composite volcano are plagioclasebearing 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 070926 to 070999 143Nd/144Nd ranges from 051213 to 051217 while the lead isotope rations vary between 18788–18851 for 206Pb/204Pb 15685–15701 for 207Pb/204Pb and 39048–39076 for 208Pb/204Pb Shoshonites show a similar pattern of trace element depletions and enrichments to the earlier ultrapotassic leucitebearing 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 precaldera ultrapotassic leucitebearing rocks 87Sr/86Sr ranges from 070665 to 070745 143Nd/144Nd ranges from 051234 to 051238 206Pb/204Pb ranges from 18924 to 19153 207Pb/204Pb ranges from 15661 to 15694 and 208Pb/204Pb ranges from 39084 to 39212 HighK calcalkaline 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 crustalderived metasomatism Interaction between the metasomatic agent and lithospheric upper mantle produced a lowmelting point metasomatised veined network The partial melting of the veins alone produced precaldera leucitebearing ultrapotassic magmas It was possibly triggered by either postcollisional 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 OIBlike astenospheric mantle material We suggest that addition of astenospheric upper mantle material from foreland mantle flowing through slab tearing after collision was achievedWe sincerely appreciate Sergio Chiesa Angelo Peccerillo and Piero Manetti for helps and discussions during the first field campaign in the late 1980s Alice Farinelli for helps during the second field campaign in the early new millenium Lia M Todaro for help with AAS analyses Lorella Francalanci for handling INA analyses on some samples and at last but not the least Leone Melluso Lorella Francalanci Simone Tommasini Giampiero E Poli and Angelo Peccerillo for stirring and focusing discussions Maurizio Ulivi provided technical support for isotope analyses Thoughtful reviews made by two anonymous peerreviewers greatly improved the original manuscript Editorial managing by Tim Grove is greatly appreciated Financial support was provided by FirenzePerugia PhD consortium during the early field campaign 1986–1987 by FIRB 2001 grant RBAU01FX8M 003 for the final field campaign 2003 and analytical work and PRIN 2007 grant 2007NS22NZ 005 for the final modelling
Keywords:
.
|
Other Papers In This Journal:
- Precise estimation of pressure–temperature paths from zoned minerals using Markov random field modeling: theory and synthetic inversion
- Formation of cordierite-bearing lavas during anatexis in the lower crust beneath Lipari Island (Aeolian arc, Italy)
- An Early Cretaceous garnet pressure–temperature path recording synconvergent burial and exhumation from the hinterland of the Sevier orogenic belt, Albion Mountains, Idaho
- Crystal reaming during the assembly, maturation, and waning of an eleven-million-year crustal magma cycle: thermobarometry of the Aucanquilcha Volcanic Cluster
- Origin of phlogopite-orthopyroxene inclusions in chromites from the Merensky Reef of the Bushveld Complex, South Africa
- An empirical garnet (YAG) – xenotime thermometer
- Magma storage and mixing conditions for the 1953–1974 eruptions of Southwest Trident volcano, Katmai National Park, Alaska
- In situ Re–Os isotopic analysis of platinum-group minerals from the Mayarí-Cristal ophiolitic massif (Mayarí-Baracoa Ophiolitic Belt, eastern Cuba): implications for the origin of Os-isotope heterogeneities in podiform chromitites
- Reply to comments by Sengupta, Raith and Dasgupta on S. B. Bhattacharya and R. K. Kar (2002)
- Trace element mapping by LA-ICP-MS: assessing geochemical mobility in garnet
- Metasomatized lithospheric mantle beneath Turkana depression in southern Ethiopia (the East Africa Rift): geochemical and Sr–Nd–Pb isotopic characteristics
- In situ observations of bubble growth in basaltic, andesitic and rhyodacitic melts
- NanoSIMS mapping and LA-ICP-MS chemical and U–Th–Pb data in monazite from a xenolith enclosed in andesite (Central Slovakia Volcanic Field)
- Phosphorus-controlled trace element distribution in zircon revealed by NanoSIMS
- Hydroxyl in olivines from mantle xenoliths in kimberlites of the Siberian platform
- Electrical conductivity of orthopyroxene and plagioclase in the lower crust
- Chromite in komatiites: 3D morphologies with implications for crystallization mechanisms
- In situ Sr isotopic analyses of epidote: tracing the sources of multi-stage fluids in ultrahigh-pressure eclogite (Ganghe, Dabie terrane)
- Source components of the Gran Canaria (Canary Islands) shield stage magmas: evidence from olivine composition and Sr–Nd–Pb isotopes
- The stability and origin of sodicgedrite in ultrahigh-temperature Mg-Al granulites: a case study from the Gondwana suture in southern India
- Plagioclase in the Skaergaard intrusion. Part 1: Core and rim compositions in the layered series
- The Campanian Ignimbrite (southern Italy) geochemical zoning: insight on the generation of a super-eruption from catastrophic differentiation and fast withdrawal
- Melting of clinopyroxene + magnesite in iron-bearing planetary mantles and implications for the Earth and Mars
- Immiscible separation of metalliferous Fe/ Ti-oxide melts from fractionating alkali basalt: P - T - f O2 conditions and two-liquid elemental partitioning
- Experimental calibration of a garnet–clinopyroxene geobarometer for mantle eclogites
- A case for hornblende dominated fractionation of arc magmas: the Chelan Complex (Washington Cascades)
- Melting phase relations of a mica–clinopyroxenite from the Milk River area, southern Alberta, Canada
- The role of slab melting in the petrogenesis of high-Mg andesites: evidence from Simbo Volcano, Solomon Islands
- Evolution of the Taupo Volcanic Center, New Zealand: petrological and thermal constraints from the Omega dacite
- Multi-stage metasomatism of diamondiferous eclogite xenoliths from the Udachnaya kimberlite pipe, Yakutia, Siberia
- Hercynian, Pan-African, Proterozoic and Archean ion-microprobe zircon ages for a Betic-Rif core complex, Alpine belt, W Mediterranean – consequences for its P - T - t path
|