Laboratory shock emplacement of noble gases, nitrogen, and carbon dioxide into basalt, and implications for trapped gases in shergottite EETA 79001

Journal Article · Mon Feb 01 04:00:00 EST 1988 · Geochim. Cosmochim. Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(88)90085-3· OSTI ID:5063958

Wiens, R C; Pepin, R O

Basalt samples have been analyzed mass spectrometrically for shock-implanted noble gases, N/sub 2/, and CO/sub 2/ after exposure to 20-60 GPa (200-600 kbar) shock in the presence of .0045-3.0 atm of ambient gas. Abundances of emplaced gases varied linearly with ambient gas pressure for constant shock pressure, and gas emplacement was most efficient in the range of 35-50 GPa shock pressure. Uncrushed samples shocked in this range gave emplacement efficiencies of 2.0-6.7% for heavy noble gases and nitrogen, while powdered samples with higher effective porosity yielded 40-50% efficiencies, indicating that approx. 50% of noble gases and nitrogen available in pores paces was emplaced. No elemental or isotopic fractionation was detected with Ar, Kr, Xe, or N/sub 2/. Helium and, in some samples, Ne were lost by diffusions subsequent to shock. Emplacement efficiencies for CO/sub 2/ averaged a factor of 1.8 +/- 0.2 greater than those of N/sub 2/ and noble gases in 4 samples with 20-50 GPa shock, and yielded 3.2 times greater efficiency in a sample shocked to 60 GPa. Enhanced CO/sub 2/ emplacement is thought to be due to reaction with silicate materials. Trapped gases in EETA 79001 glass were probably emplaced by shock. However, apparent emplacement efficiencies are somewhat higher than even shocked powder samples. Possible explanations for the difference include atmospheric overpressure at the time of shock, trapping of gas already in vugs by intruding melt material, or collapse of gas-filled vugs to form gas-laden glass inclusions.

• Research Organization: Univ. of Minnesota, Minneapolis (USA)
• OSTI ID: 5063958
• Journal Information: Geochim. Cosmochim. Acta; (United States), Journal Name: Geochim. Cosmochim. Acta; (United States) Vol. 52:2; ISSN GCACA
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580400* -- Geochemistry-- (-1989)
ATMOSPHERIC CHEMISTRY
BASALT
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMISTRY
COMPARATIVE EVALUATIONS
ELEMENTS
FEDERAL REGION VI
FLUIDS
GASES
IGNEOUS ROCKS
IMPACT SHOCK
INCLUSIONS
MARS PLANET
MASS SPECTROSCOPY
METEORITES
NEW MEXICO
NITROGEN
NONMETALS
NORTH AMERICA
OXIDES
OXYGEN COMPOUNDS
PLANETS
QUANTITATIVE CHEMICAL ANALYSIS
RARE GASES
ROCKS
SPECTROSCOPY
USA
VOLCANIC ROCKS