Nitrogen isotopic composition and density of the Archean atmosphere.
Understanding the atmosphere's composition during the Archean eon is fundamental to unraveling ancient environmental conditions. We show from the analysis of nitrogen and argon isotopes in fluid inclusions trapped in 3.0- to 3.5-billion-year-old hydrothermal quartz that the partial pressure of N2 of the Archean atmosphere was lower than 1.1 bar, possibly as low as 0.5 bar, and had a nitrogen isotopic composition comparable to the present-day one. These results imply that dinitrogen did not play a significant role in the thermal budget of the ancient Earth and that the Archean partial pressure of CO2 was probably lower than 0.7 bar.
Centre de Recherches Pétrographiques et Géochimiques-CNRS, Université de Lorraine, 15 rue Notre Dame des Pauvres, 54501 Vandoeuvre-lès-Nancy Cedex, France. bmarty@crpg.cnrs-nancy.fr
Bernard
B
Marty
Laurent
L
Zimmermann
Magali
M
Pujol
Ray
R
Burgess
Pascal
P
Philippot
D001272:Atmosphere / Q000032:analysis / Q000737:chemistry*; D009587:Nitrogen Isotopes / Q000032:analysis / Q000737:chemistry*; D010313:Partial Pressure
D009587:Nitrogen Isotopes