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Detection of small amounts of N (sub 2) in CO (sub 2) -rich high-density fluid inclusions from mantle xenoliths

Marta Berkesi, Reka Kaldos, Munjae Park, Csaba Szabo, Tamas Vaczi, Kalman Torok, Bianca Nemeth and Gyorgy Czuppon
Detection of small amounts of N (sub 2) in CO (sub 2) -rich high-density fluid inclusions from mantle xenoliths
European Journal of Mineralogy (December 2016) 29 (3): 423-431


Fluid inclusions (FIs) (n = 34) in spinel lherzolite xenoliths derived from the subcontinental lithospheric mantle from Jeju Island (S. Korea), the Rio Grande Rift (New-Mexico, USA) and Mt. Quincan (Australia) were analysed using confocal Raman spectroscopy. Despite the significant geographical distances, the studied rocks and their FIs show similar petrographic features. We show evidence for the presence of small amounts of nitrogen in extreme high density (> or =1 g/cm (super 3) ) FIs from the deep lithospheric mantle using Raman spectroscopy with a spectral resolution between 0.6 and 0.7 cm (super -1) . The only nitrogen-bearing species found in the inclusions was N (sub 2) . The N (sub 2) Raman signal appeared as two adjacent, partially overlapping bands. The band at higher Raman shift is identical with the nitrogen-in-air (N (sub 2) (super air) ) band. The band at lower Raman shift is therefore nitrogen within the FIs (N (sub 2) (super fluid) ). The relative amounts of CO (sub 2) and N (sub 2) within the FIs were calculated using the integrated band areas. In the studied ultramafic xenoliths, N (sub 2) concentrations varied between 0.2 and 1.8 mol%, with one exceptionally high concentration of 3.1 mol%. We believe that microthermometric measurements and/or Raman spectroscopy with an inferior spectral resolution may leave N (sub 2) undetected in CO (sub 2) -rich upper mantle FIs. Based on our observations, we propose that N (sub 2) may be a minor but common component in subcontinental lithospheric upper-mantle fluids.

ISSN: 0935-1221
EISSN: 1617-4011
Serial Title: European Journal of Mineralogy
Serial Volume: 29
Serial Issue: 3
Title: Detection of small amounts of N (sub 2) in CO (sub 2) -rich high-density fluid inclusions from mantle xenoliths
Affiliation: Eotvos University, Lithosphere Fluid Research Laboratory, Budapest, Hungary
Pages: 423-431
Published: 20161227
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Germany
References: 66
Accession Number: 2017-006182
Categories: Igneous and metamorphic petrologyGeochemistry of rocks, soils, and sediments
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table
N33°12'00" - N33°34'60", E126°10'00" - E126°49'60"
N17°18'11" - N17°18'11", E145°34'39" - E145°34'39"
Secondary Affiliation: Seoul National University, KOR, South KoreaHungarian Geological and Geophysical Institute, HUN, HungaryHungarian Academy of Sciences, Institute for Geological and Geochemical Research, HUN, Hungary
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, copyright, Schweizerbart'sche Verlagsbuchhandlung. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201705
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