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Thermal-gradient-induced non-mass-dependent isotope fractionation
1Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803-4101, USA. tsun1@lsu.edu
Rapid Communications in Mass Spectrometry : RCM
|February 22, 2011
Summary
Non-mass-dependent isotope anomalies in oxygen (O2) and sulfur hexafluoride (SF6) gases were generated by thermal gradients. A nuclear spin effect on gas diffusion is proposed as the cause, explaining natural isotope anomalies.
Area of Science:
- Geochemistry
- Physical Chemistry
- Planetary Science
Background:
- Isotope fractionation is typically mass-dependent.
- Previous studies observed non-mass-dependent oxygen-17 anomalies in O2 under thermal gradients.
Purpose of the Study:
- Investigate the mechanism behind non-mass-dependent isotope anomalies.
- Determine the influence of experimental parameters on these anomalies.
Main Methods:
- Subjected O2 and SF6 gases to thermal gradients.
- Varied gas pressure, experimental duration, and apparatus geometry.
- Measured oxygen-17 and sulfur-33/sulfur-36 anomalies.
Main Results:
- Confirmed generation of non-mass-dependent (17)O anomalies in O2.
- Observed similar anomalies for (33)S and (36)S in SF6.
- Results align with a proposed nuclear spin effect on gas diffusion.
Conclusions:
- A nuclear spin effect on gas diffusion likely causes these anomalies.
- This mechanism explains puzzling non-mass-dependent isotope signatures in nature.
- Provides insights into solar system isotope heterogeneity.
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