Helium–strontium isotope constraints on mantle evolution beneath the Roman Comagmatic Province, Italy

Martelli, M.; Nuccio, P. M.; Stuart, Finlay M.; Burgess, R.; Ellam, Robert M.; Italiano, Francesco

doi:10.1016/j.epsl.2004.05.025

Cited by 107 publications

(105 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Ages in parenthesis. He ratios (R/Ra), and distribution of helium isotopes in Italy, measured in gas sampled at surface, and in fluid inclusions from Plio-Quaternary magma phenocrysts (olivine and clinopyroxene) and from mantle xenoliths (Minissale, 2004;Martelli et al, 2004;. N = number of measurements.…”

mentioning

confidence: 99%

Carbonate metasomatism and CO2 lithosphere–asthenosphere degassing beneath the Western Mediterranean: An integrated model arising from petrological and geophysical data

2009

View full text Add to dashboard Cite

We present an integrated petrological, geochemical, and geophysical model that offers an explanation for the present-day anomalously high non-volcanic deep (mantle derived) CO 2 emission in the Tyrrhenian region. We investigate how decarbonation or melting of carbonate-rich lithologies from a subducted lithosphere may affect the efficiency of carbon release in the lithosphere-asthenosphere system. We propose that melting of sediments and/or continental crust of the subducted Adriatic-Ionian (African) lithosphere at pressure greater than 4 GPa (130 km) may represent an efficient mean for carbon cycling into the upper mantle and into the exosphere in the Western Mediterranean area. Melting of carbonated lithologies, induced by the progressive rise of mantle temperatures behind the eastward retreating Adriatic-Ionian subducting plate, generates low fractions of carbonate-rich (hydrous-silicate) melts. Due to their low density and viscosity, such melts can migrate upward through the mantle, forming a carbonated partially molten CO 2 -rich mantle recorded by tomographic images in the depth range from 130 to 60 km. Upwelling in the mantle of carbonate-rich melts to depths less than 60 -70 km, induces massive outgassing of CO 2 . Buoyancy forces, probably favored by fluid overpressures, are able to allow migration of CO 2 from the mantle to the surface, through deep lithospheric faults, and its accumulation beneath the Moho and within the lower crust. The present model may also explain CO 2 enrichment of the Etna active volcano. Deep CO 2 cycling is tentatively quantified in terms of conservative carbon mantle flux in the investigated area. IntroductionThe role of Earth degassing in present-day global carbon budget and consequent climate effects has been focused chiefly on volcanic emissions (e.g. Gerlach, 1991a;Varekamp and Thomas, 1998, Kerrick, 2001). The non-volcanic 1 escape of CO 2 from the upper mantle, from crustal carbonate rocks, from hydrocarbon accumulations, and from geothermal fields is not considered in the budgets of natural release processes (cf. IPCC reports). However, the impact of these processes on atmospheric CO 2 budget is relevant if considered at the regional scale.Italy constitutes an extraordinary example of massive CO 2 subaerial fluxes in the Western Mediterranean region (e.g. Chiodini et al., 1999Chiodini et al., , 2004Rogie et al., 2000;Chiodini and Frondini 2001;Minissale, 2004). In Italy, CO 2 emissions occur both in those areas of young or active volcanism (e.g. the Tyrrhenian border of Central Italy; Fig. 1), and at zones in which there is no evidence of magmatic activity, such as Central and Southern Apennines (Fig. 1).Interactions between magmas and carbonate rocks at walls of magma chambers locally contribute CO 2 in some recent and active volcanic zones (e.g., Alban Hills, Mt. Ernici, Vesuvius;Federico and Peccerillo, 2002; Iacono Marziano et al., 2007a, b). However, the bulk of present-day soil degassing in Italy is a regional feature affecting both volcanic areas and z...

show abstract

mentioning

confidence: 99%

Carbonate metasomatism and CO2 lithosphere–asthenosphere degassing beneath the Western Mediterranean: An integrated model arising from petrological and geophysical data

2009

View full text Add to dashboard Cite

show abstract

“…The occurrence of such excesses only in Neapolitan rocks is ascribed to the recent addition of a U-rich component requiring the occurrence of a fluid component, which is also expected to act as The Vesuvius and the other volcanoes of Central Italy (Walker et al, 1989) and a possible crustal component represented by an Italian crustal rocks reported in Conticelli et al (2007) with 52 ppt Os and 187 Os/ 188 Os = 1.004. Data are from Gasperini et al (2002), Conticelli et al (2002Conticelli et al ( , 2007, Martelli et al (2004), Widom et al (2004), Prelević et al (2008Prelević et al ( , 2010Prelević et al ( , 2014, and Tommasini's unpublished data. Mantle Zoo end members are from Stracke et al (2005).…”

Section: Excursion Notesmentioning

confidence: 99%

“…13C) also indicate a recycled crustal component in the mantle source of magmas (Martelli et al, 2004). Avanzinelli et al (2008) reported a comprehensive study of U-Th disequilibria on the youngest Italian rocks with the aim of investigating the mechanism of source melting (Fig.…”

Section: Excursion Notesmentioning

confidence: 99%

The Vesuvius and the other volcanoes of Central Italy

Avanzinelli¹,

Cioni²,

Conticelli³

et al. 2017

GFT

View full text Add to dashboard Cite

“…Fig. 11 extends to Northern Africa the regional (N to S) isotopic trends, originally derived from the analysis of a variety of fluid types (natural gas discharges, dissolved gasses in groundwater, fluid inclusions in volcanic rocks) collected from seismically or volcanically active districts of northern-central (Tuscany) to southern (Sicily) Italy Martelli et al, 2004Martelli et al, , 2008. It shows that the Italian mantle gas anomaly only marginally extends to northwestern Africa, and that the north to south trend of increasing R/Ra ratios, from the Tuscany, Roman and Campanian Magmatic Provinces ( Mahood and Hildreth (1983) on the exceptional nature of Pantelleria volcanism, confirming that crustal thinning in the Sicily channel is unambiguously acting as a preferential path for upper mantle degassing at the regional scale.…”

Section: Helium Isotopes Distribution: Links With Geodynamicsmentioning

confidence: 99%

“…Spatial variations of the He ratios can thus be used to identify contemporary magmatic activity and/or tectonic processes that may facilitate the transport of mantle volatiles to shallow crustal levels (Polyak et al, 2000;Caracausi et al, 2005;Pik and Marty, 2009) and provide valuable information about regional tectonic environments. The application of the above "isotopic approach" to Italian gas discharges for instance, has revealed a complex scenario in which an heterogeneous (variably metasomatized) mantle, and gas production in the crust, both contribute to the source of the surface gas anomaly (e.g., Chiodini et al, 2000Chiodini et al, , 2004Parello et al, 2000;Martelli et al, 2004Martelli et al, , 2008.…”

Section: Introductionmentioning

confidence: 99%

Regional variations in the chemical and helium–carbon isotope composition of geothermal fluids across Tunisia

et al. 2011

View full text Add to dashboard Cite

Tunisia has numerous thermo-mineral springs. Previous studies have shown that their chemical composition and occurrence are strongly influenced by the regional geology. However little work has been done so far to study the isotopic composition of volatiles associated with these geothermal manifestations. Here, we report on the results of an extensive survey of both natural hot springs and production wells across Tunisia, aimed at investigating the spatial distribution of thermal fluids' geochemical characteristics and He-C isotopic composition. The chemistry of the analyzed samples highlights the heterogeneity of the water mineralization processes in Tunisia, as a consequence of the complex geological and tectonic setting of the country. In terms of chemical composition, we are able to conclude, however, that dissolution of halite and gypsum plays a key control on groundwater chemistry. Helium and carbon isotope systematics confirm the prevalently crustal origin of the volatiles interacting with the aquifer systems, consistent with the absence of any recent magmatism. Most samples are characterized by crustal-type helium ( He ratio reaches 2.4 Ra (corresponding to 30% of mantle-derived helium) at the Ain Garci site, a CO 2 rich mineral spring located some 30 km south of the city of Zaghouan. This mantle signature is consistent with the fact that the Pelagian Block, to which Eastern Tunisia belongs, has been deeply affected by extensional and transtensional tectonics since the opening of the Tethys, a process which is still ongoing in the Sicily channel (Pantelleria Rift). As a whole however, our results show that the Italian mantle gas anomaly only marginally extends to Northwestern Africa.

show abstract

Helium–strontium isotope constraints on mantle evolution beneath the Roman Comagmatic Province, Italy

Cited by 107 publications

References 50 publications

Carbonate metasomatism and CO2 lithosphere–asthenosphere degassing beneath the Western Mediterranean: An integrated model arising from petrological and geophysical data

Carbonate metasomatism and CO2 lithosphere–asthenosphere degassing beneath the Western Mediterranean: An integrated model arising from petrological and geophysical data

The Vesuvius and the other volcanoes of Central Italy

Regional variations in the chemical and helium–carbon isotope composition of geothermal fluids across Tunisia

Contact Info

Product

Resources

About