scholarly journals Modelled isotopic fractionation and transient diffusive release of methane from potential subsurface sources on Mars

Icarus ◽  
2017 ◽  
Vol 281 ◽  
pp. 240-247 ◽  
Author(s):  
Adam H. Stevens ◽  
Manish R. Patel ◽  
Stephen R. Lewis
2021 ◽  
Vol 565 ◽  
pp. 116954
Author(s):  
Xiao-Jun Wang ◽  
Li-Hui Chen ◽  
Takeshi Hanyu ◽  
Yuan Zhong ◽  
Jin-Hua Shi ◽  
...  

Author(s):  
John N. Christensen ◽  
James M. Watkins ◽  
Laurent S. Devriendt ◽  
Donald J. DePaolo ◽  
Mark E. Conrad ◽  
...  

2020 ◽  
Vol 117 (35) ◽  
pp. 21125-21131 ◽  
Author(s):  
Jing-Liang Guo ◽  
Zaicong Wang ◽  
Wen Zhang ◽  
Frédéric Moynier ◽  
Dandan Cui ◽  
...  

Zircons widely occur in magmatic rocks and often display internal zonation finely recording the magmatic history. Here, we presented in situ high-precision (2SD <0.15‰ for δ94Zr) and high–spatial-resolution (20 µm) stable Zr isotope compositions of magmatic zircons in a suite of calc-alkaline plutonic rocks from the juvenile part of the Gangdese arc, southern Tibet. These zircon grains are internally zoned with Zr isotopically light cores and increasingly heavier rims. Our data suggest the preferential incorporation of lighter Zr isotopes in zircon from the melt, which would drive the residual melt to heavier values. The Rayleigh distillation model can well explain the observed internal zoning in single zircon grains, and the best-fit models gave average zircon–melt fractionation factors for each sample ranging from 0.99955 to 0.99988. The average fractionation factors are positively correlated with the median Ti-in-zircon temperatures, indicating a strong temperature dependence of Zr isotopic fractionation. The results demonstrate that in situ Zr isotope analyses would be another powerful contribution to the geochemical toolbox related to zircon. The findings of this study solve the fundamental issue on how zircon fractionates Zr isotopes in calc-alkaline magmas, the major type of magmas that led to forming continental crust over time. The results also show the great potential of stable Zr isotopes in tracing magmatic thermal and chemical evolution and thus possibly continental crustal differentiation.


Proceedings ◽  
2019 ◽  
Vol 46 (1) ◽  
pp. 26
Author(s):  
Pranjal Sharma ◽  
Ankit Agarwal ◽  
Bhawna Chaudhary

In recent years, geologists have put in a lot of effort trying to study the evolution of Earth using different techniques studying rocks, gases, and water at different channels like mantle, lithosphere, and atmosphere. Some of the methods include estimation of heat flux between the atmosphere and sea ice, modeling global temperature changes, and groundwater monitoring networks. That being said, algorithms involving the study of Earth’s evolution have been a debated topic for decades. In addition, there is distinct research on the mantle, lithosphere, and atmosphere using isotopic fractionation, which this paper will take into consideration to form genes at the former stage. This factor of isotopic fractionation could be molded in QGA to study the Earth’s evolution. We combined these factors because the gases containing these isotopes move from mantle to lithosphere or atmosphere through gaps or volcanic eruptions contributing to it. We are likely to use the Rb/Sr and Sm/Nd ratios to study the evolution of these channels. This paper, in general, provides the idea of gathering some information about temperature changes by using isotopic ratios as chromosomes, in QGA the chromosomes depict the characteristic of a generation. Here these ratios depict the temperature characteristic and other steps of QGA would be molded to study these ratios in the form of temperature changes, which would further signify the evolution of Earth based on the study that temperature changes with the change in isotopic ratios. This paper will collect these distinct studies and embed them into an upgraded quantum genetic algorithm called Quantum Genetic Terrain Algorithm or Quantum GTA.


Science ◽  
1963 ◽  
Vol 139 (3551) ◽  
pp. 224-226 ◽  
Author(s):  
J. N. Rosholt ◽  
W. R. Shields ◽  
E. L. Garner

1974 ◽  
Vol 11 (10) ◽  
pp. 1350-1356 ◽  
Author(s):  
A. K. Baksi

The 36Ar content of a 50 m thick lava flow shows minima at a depth of around 37 m, as well as at the bottom chilled margin, suggesting that most of the atmospheric argon entered the solidifying lava flow from the air above it. Measurement of the 36Ar/38Ar ratios indicates that little or no isotopic fractionation occurred during this process. The K–Ar 'isochron' age of the S.P. Flow is about 70 000 years.


1981 ◽  
Vol 46 (16) ◽  
pp. 3344-3346 ◽  
Author(s):  
Crist N. Filer ◽  
Robert Fazio ◽  
David G. Ahern

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