scholarly journals Nitrogen Isotopic Composition and Density of the Archean Atmosphere

Science ◽  
2013 ◽  
Vol 342 (6154) ◽  
pp. 101-104 ◽  
Author(s):  
Bernard Marty ◽  
Laurent Zimmermann ◽  
Magali Pujol ◽  
Ray Burgess ◽  
Pascal Philippot
Keyword(s):  
Isotopic Composition ◽  
Partial Pressure ◽  
Significant Role ◽  
Fluid Inclusions ◽  
Environmental Conditions ◽  
Thermal Budget ◽  
Hydrothermal Quartz ◽  
Nitrogen Isotopic Composition ◽  
Argon Isotopes

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 pressureof N2of 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 CO2was probably lower than 0.7 bar.

scholarly journals Ar–Ar dating for hydrothermal quartz from the 2.4 Ga Ongeluk Formation, South Africa: implications for seafloor hydrothermal circulation

2018 ◽  
Vol 5 (9) ◽  
pp. 180260
Author(s):  
Takuya Saito ◽  
Hua-Ning Qiu ◽  
Takazo Shibuya ◽  
Yi-Bing Li ◽  
Kouki Kitajima ◽  
...  
Keyword(s):  
South Africa ◽  
Fluid Inclusion ◽  
Fluid Inclusions ◽  
Hydrothermal System ◽  
Magmatic Fluid ◽  
Crustal Fluid ◽  
Hydrothermal Quartz ◽  
Argon Isotopes ◽  
Stepwise Crushing ◽  
Binary Mixing

Fluid inclusions in hydrothermal quartz in the 2.4 Ga Ongeluk Formation, South Africa, are expected to partially retain a component of the ancient seawater. To constrain the origin of the fluid and the quartz precipitation age, we conducted Ar–Ar dating for the quartz via a stepwise crushing method. The obtained argon isotopes show two or three endmembers with one or two binary mixing lines as the crushing proceeds, suggesting that the isotopic compositions of these endmembers correspond to fluid inclusions of each generation, earlier generated smaller 40 Ar- and K-rich inclusions, moderate 40 Ar- and 38 Ar Cl (neutron-induced 38 Ar from Cl)-rich inclusions and later generated larger atmospheric-rich inclusions. The K-rich inclusions show significantly different 40 Ar/ 38 Ar Cl values compared to the 38 Ar Cl -rich inclusions, indicating that it is difficult to constrain the quartz formation age using only fluid inclusions containing excess 40 Ar. The highest obtained 40 Ar/ 36 Ar value from the fluid inclusions is consistent with an expected value of the Ongeluk plume source, suggesting that the quartz precipitation was driven by Ongeluk volcanism. Considering the fluid inclusion generations and their compositions, the hydrothermal system was composed of crustal fluid and magmatic fluid without seawater before the beginning of a small amount of seawater input to the hydrothermal system.

The source and significance of argon isotopes in fluid inclusions from areas of mineralization

1986 ◽  
Vol 79 (3-4) ◽  
pp. 303-318 ◽  
Author(s):  
S. Kelley ◽  
G. Turner ◽  
A.W. Butterfield ◽  
T.J. Shepherd
Keyword(s):  
Fluid Inclusions ◽  
Argon Isotopes

scholarly journals Study of Morphometric Aspects of Eri Silkworm (Samia ricini D.) reared on the host plant

2020 ◽  
pp. 192-196
Keyword(s):  
Host Plant ◽  
Significant Role ◽  
Environmental Conditions ◽  
Ricinus Communis ◽  
Larval Period ◽  
Larval Duration ◽  
Larval Weight ◽  
Larval Length ◽  
Qualitative Characters

The environmental conditions play a significant role and influence the quantitative and qualitative characters of silkworm such as larval length, larval breadth, larval weight and larval duration. Larvae of Eri silkworm (Samia ricini D.) were reared on Castor leaves (Ricinus communis). The data that were recorded for larval length (cm) from first to fifth instar are 0.76 ± 0.003; 1.49 ± 0.023; 3.09 ± 0.020; 4.39 ± 0.04 and 6.57 ± 0.04 respectively, for larval breadth (cm) are 0.122 ± 0.007; 0.24 ± 0.0; 0.46 ± 0.0; 0.74 ± 0.0 and 1.14 ± 0.0 respectively and for larval weight (g) are 0.007 ± 0.01; 0.033 ± 0.02; 0.37 ± 0.01; 1.07 ± 0.02 and 3.74 ± 0.03 respectively and the larval period of the reared larvae lasted for about 20 days.

Nitrogen isotopic composition in hair protein is different in liver cirrhotic patients

2006 ◽  
Vol 20 (19) ◽  
pp. 2973-2978 ◽  
Author(s):  
Klaus J. Petzke ◽  
Thomas Feist ◽  
Wolfgang E. Fleig ◽  
Cornelia C. Metges
Keyword(s):  
Isotopic Composition ◽  
Nitrogen Isotopic Composition ◽  
Cirrhotic Patients
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