scholarly journals Erratum: 13C/12C and 18O/16O liquid–vapor isotopic fractionation factors in CO as a function of temperature [J. Chem. Phys. 70, 5731 (1979)]

1982 ◽  
Vol 77 (10) ◽  
pp. 5260-5261
Author(s):  
Myung W. Lee ◽  
Jacob Bigeleisen
Keyword(s):  
Isotopic Fractionation ◽  
Chem Phys ◽  
Fractionation Factors ◽  
Liquid Vapor

13C/12C and18O/16O liquid–vapor isotopic fractionation factors in CO as a function of temperature

1979 ◽  
Vol 70 (12) ◽  
pp. 5731-5738 ◽  
Author(s):  
Dieter Götz ◽  
Myung W. Lee ◽  
Jacob Bigeleisen
Keyword(s):  
Isotopic Fractionation ◽  
Fractionation Factors ◽  
Liquid Vapor

scholarly journals Significant Zr isotope variations in single zircon grains recording magma evolution history

2020 ◽  
Vol 117 (35) ◽  
pp. 21125-21131 ◽  
Author(s):  
Jing-Liang Guo ◽  
Zaicong Wang ◽  
Wen Zhang ◽  
Frédéric Moynier ◽  
Dandan Cui ◽  
...  
Keyword(s):  
Isotopic Fractionation ◽  
Major Type ◽  
Strong Temperature Dependence ◽  
Calc Alkaline ◽  
Southern Tibet ◽  
Rayleigh Distillation ◽  
Single Zircon ◽  
Magmatic History ◽  
Fractionation Factors

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.

scholarly journals Dating of Groundwater Recharge in Two Small Adjacent Aquifers in Israel and Their Initial 14C Activities

Radiocarbon ◽  
2011 ◽  
Vol 53 (1) ◽  
pp. 137-149 ◽  
Author(s):  
J Guttman ◽  
J Kronfeld ◽  
I Carmi
Keyword(s):  
Groundwater Recharge ◽  
Unsaturated Zone ◽  
Hydraulic Properties ◽  
Isotopic Fractionation ◽  
Apparent Difference ◽  
Pleistocene Aquifer ◽  
Fractionation Factors

Radiocarbon and tritium determinations were carried out in 2 adjacent small aquifers in Israel. These aquifers have small storage capacities and good hydraulic properties. Darcy calculations suggest that the aquifers contain young waters, ≃50 yr in age. 14C concentrations in the Pleistocene aquifer are between 23–60 pMC, with the lowest activity related to contamination by petroleum-based fertilizers with no 14C. 14C concentrations in the Judea Group aquifer range from 62 to 95 pMC. An apparent difference of ≃1000 yr is indicated for the average recharge age between the 2 aquifers. The tritium data suggests that the water in both aquifers is quite young. The 1000-yr difference is an artifact of initial isotopic fractionation differences through the unsaturated zone as established elsewhere for these 2 aquifers. When these individual fractionation factors (0.54 for the Pleistocene and 0.62 for the Judea Group) are used, it is revealed that both aquifers contain young water, in agreement with the Darcy calculation, which was recharged at the beginning of the period of thermonuclear atmospheric testing in the early 1960s.

Sign in / Sign up

Export Citation Format

Share Document