The five stable noble gases or “rare gases”, Helium, Neon, Argon, Krypton, and Xenon, are chemically inert, making them good tracers for physical processes. Due to their elevated volatility, they have a strong affinity for the gas phase. Noble gases provide a group of 23 stable isotopes widely used to investigate physical processes in nature (earth and extra-terrestrial systems ).

Three major terrestrial reservoirs contribute to noble gas inventory in terrestrial fluids (water, gas, oil):

  • Atmosphere and Air Saturated Water (ASW)
  • Solid-Earth-derived fluids, related to the radiogenic or nucleogenic production, from parent radionuclide dispersed in the rock matrix and/or in embedded fluids
  • Mantle fluids have a significantly different signature from the other reservoirs mainly for high 3He enrichment in fluids.

All these reservoirs have a quite distinct chemical and isotopic signature that allows for efficient tracing of the different relative contribution in geological matrices.

Noble gases have found large application as tracers in: hydrogeology, geothermal prospection/exploitation, volcanology, gas/oil reservoirs management, viability assessment of CO2 geological storage, further to as indicators of: climate variations in ice cores, pore sediments and fluid inclusions in stalagmites, and degassing/mixing processes during the formation of the Solar system and of the Earth.

INSTRUMENTS

The research and services at the Rare Gas Lab are based on the use of noble gases to determine the origin of fluids from different tectonic environments.

The Rare Gas lab contains a mass spectrometer system, capable of precise isotopic measurements of the noble gases, made up of:

  • a Mass Analyser Products Ltd. MAP215-50 noble gas mass spectrometer
  • a SpectraLab200 Quadrupole mass spectrometer
  • a UHV gas inlet system equipped with a cryostat and designed to be versatile and to extract noble gases from a variety of materials.

STAFF

Dr. Gabriella Magro (Ricercatore CNR - Responsabile Laboratorio)
Ph.D. Fabrizio Gherardi (Ricercatore CNR)

CONTACTS

Phone:

+39 050 6212337 (Dr. Gabrilella Magro - Office)
+39 050 6212271 (Laboratory)
+39 050 6212316 (Ph.D. Fabrizio Gherardi - Office)

E-mail:

gabriella.magro(at)igg.cnr(dot)it
fabrizio.gherardi(at)igg.cnr(dot)it

METHODS AND APPLICATIONS

The method has been applied in the past years to:

  • volcanic surveillance and risk mitigation
  • noble gases isotopic fingerprint of water and associated free gases for deciphering the different sources and related tectonic environments
  • geochemical exploration for mineral, geothermal and hydrocarbons resources
  • geothermal and oil field management

PROJECTS

During the past years the IGG Rare Gas laboratory has been actively involved in several scientific projects funded by :

  • IAEA (IAEA TC Project no.PHI/8/023 “Geochemistry for geothermal resources management in the Philippines”)
  • European Union (CEE EV5V-CTP3-0285 “Santorini Volcano Laboratory Geochemistry”, ERB-CHRX-CT94-0567 (KATRIN) “A multi-disciplinary global approach of groundwater flows in karstic areas and its consequences for water resources and environment studies”, DESCRAMBLE, “Drilling in supercritical geothermal conditions”
  • Oil companies (eni)
  • Geothermal companies (ENEL)

MAIN SCIENTIFIC INTERESTS

  • Noble gases from supercritical fluids
  • Noble gases in enhanced geothermal systems
  • Noble gases fingerprinting of hydrocarbons in different tectonic settings
  • Noble gases associated to mud volcanoes and saline waters

SELECTED PUBLICATIONS

  • Bellani, S, Magro,G. and Gherardi, F.(2015) Heat Flow and Helium Isotopes in the Geothermal Areas of Tuscany (Central Italy) GRC Transactions, Vol. 39, 399-405
  • Magro, G., Gherardi, F., Bayon, F.E.B. (2013) Noble and reactive gases of Palinpinon geothermal field (Philippines): Origin, reservoir processes and geodynamic implications. Chemical Geology, 339, 4-15.
  • Magro, G., Gherardi, F., Bellani, S. (2010) Noble gases in karstic and thermal waters of Strimon basin (Greece-Bulgaria) Water-Rock Interaction - Proceedings of the 13th International Conference on Water-Rock Interaction, WRI-13, 345-348.
  • Magro, G., Bellani, S., Della Vedova, B. (2009) The deep roots of the Larderello geothermal field (Italy) from heat flux and 3He anomalies Transactions - Geothermal Resources Council, 33, pp. 360-365.
  • Bayon, F.E.B., See, F.S., Magro, G., Pennisi, M. (2008) Noble gas and boron isotopic signatures of the Bacon-Manito geothermal fluid, Philippines. Geofluids, 8 (4), 230-238.
  • Aguilera, E., Cioni, R., Gherardi, F., Magro, G., Marini, L., Pang, Z. (2005) Chemical and isotope characteristics of the Chachimbiro geothermal fluids (Ecuador) Geothermics, 34 (4), 495-517.
  • Dallai, L., Magro, G., Petrucci, E., Ruggieri, G. (2005) Stable isotope and noble gas isotope compositions of inclusion fluids from Larderello geothermal field (Italy): Constraints to fluid origin and mixing processes Journal of Volcanology and Geothermal Research, 148 (1-2), 152-164.
  • Magro, G., G. Ruggieri, G. Gianelli, S. Bellani, and G. Scandiffio, (2003) Helium isotopes in paleofluids and present-day fluids of the Larderello geothermal field: Constraints on the heat source, J. Geophys. Res., 108(B1), 2003, doi:10.1029/2001JB001590, 2003.
  • Minissale, A., Kerrick, D.M., Magro, G., Murrell, M.T., Paladini, M., Rihs, S., Sturchio, N.C., Tassi, F., Vaselli, O. (2002) Geochemistry of Quaternary travertines in the region north of Rome (Italy): Structural, hydrologic and paleoclimatic implications. Earth and Planetary Science Letters, 203 (2),709-728.
  • Vaselli, O., Minissale, A., Tassi, F., Magro, G., Seghedi, I., Ioane, D., Szakacs, A. (2002) A geochemical traverse across the Eastern Carpathians (Romania): Constraints on the origin and evolution of the mineral water and gas discharges Chemical Geology, 182 (2-4), 637-654.
  • Minissale, G. Magro, G. Martinelli, O. Vaselli, G.F. Tassi, (2000) Fluid geochemical transect in the Northern Apennines (central-northern Italy): fluid genesis and migration and tectonic implications, Tectonophysics, Volume 319, Issue 3, 199-222
  • Minissale, A., Vaselli, O., Chandrasekharam, D., Magro, G., Tassi, F., Casiglia, A. (2000) Origin and evolution of 'intracratonic' thermal fluids from central-western peninsular India Earth and Planetary Science Letters, 181 (3), 377-394.