scholarly journals Stable-Isotope Ratios and Concentration of CO2 in Air from Polar Ice Cores

1988 ◽  
Vol 10 ◽  
pp. 151-156 ◽  
Author(s):  
U. Siegenthaler ◽  
H. Friedli ◽  
H. Loetscher ◽  
E. Moor ◽  
A. Neftel ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Atmospheric Carbon Dioxide ◽  
Isotope Fractionation ◽  
Ice Core ◽  
Ice Cores ◽  
South Pole ◽  
Polar Ice ◽  
Isotopic Equilibrium ◽  
Calculated Equilibrium ◽  
Fractionation Factors

Analyses of air trapped in an ice core from the South Pole indicate that the CO2 concentration may have increased by about 10 ppm and that the 13C/12C ratio decreased slightly in the thirteenth century. These changes, if really of atmospheric origin, must be due to a significant input into the atmosphere of CO2, either of biogenic or of oceanic origin. 18O/16O ratios in CO2 from different ice cores are much lower than those which have been observed in atmospheric carbon dioxide. A possible explanation is that the CO2 has equilibrated isotopically with the ice. We have calculated equilibrium isotope-fractionation factors between ice and carbon dioxide and found that the observed 18O/16O ratios of CO2 are indeed near isotopic equilibrium with the ice. This indicates that an exchange of oxygen atoms probably occurs between ice and included CO2.

scholarly journals Stable-Isotope Ratios and Concentration of CO2in Air from Polar Ice Cores

1988 ◽  
Vol 10 ◽  
pp. 151-156 ◽  
Author(s):  
U. Siegenthaler ◽  
H. Friedli ◽  
H. Loetscher ◽  
E. Moor ◽  
A. Neftel ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Atmospheric Carbon Dioxide ◽  
Isotope Fractionation ◽  
Ice Core ◽  
Ice Cores ◽  
South Pole ◽  
Polar Ice ◽  
Isotopic Equilibrium ◽  
Calculated Equilibrium ◽  
Fractionation Factors

Analyses of air trapped in an ice core from the South Pole indicate that the CO2concentration may have increased by about 10 ppm and that the13C/12C ratio decreased slightly in the thirteenth century. These changes, if really of atmospheric origin, must be due to a significant input into the atmosphere of CO2, either of biogenic or of oceanic origin.18O/16O ratios in CO2from different ice cores are much lower than those which have been observed in atmospheric carbon dioxide. A possible explanation is that the CO2has equilibrated isotopically with the ice. We have calculated equilibrium isotope-fractionation factors between ice and carbon dioxide and found that the observed18O/16O ratios of CO2are indeed near isotopic equilibrium with the ice. This indicates that an exchange of oxygen atoms probably occurs between ice and included CO2.

scholarly journals Algal constraints on the Cenozoic history of atmospheric CO<sub>2</sub>?

2007 ◽  
Vol 4 (1) ◽  
pp. 1-11 ◽  
Author(s):  
J. Henderiks ◽  
R. E. M. Rickaby
Keyword(s):  
Carbon Dioxide ◽  
Temperature Sensitivity ◽  
Atmospheric Carbon Dioxide ◽  
Fossil Fuels ◽  
Ice Core ◽  
Atmospheric Composition ◽  
Polar Ice ◽  
Extant Species ◽  
History Of ◽  
Evolutionary Memory

Abstract. An urgent question for future climate, in light of increased burning of fossil fuels, is the temperature sensitivity of the climate system to atmospheric carbon dioxide (pCO2). To date, no direct proxy for past levels of pCO2 exists beyond the reach of the polar ice core records. We propose a new methodology for placing an upper constraint on pCO2 over the Cenozoic based on the living geological record. Specifically, our premise is that the contrasting calcification tolerance of various extant species of coccolithophore to raised pCO2 reflects an "evolutionary memory" of past atmospheric composition. The different times of first emergence of each morphospecies allows an upper constraint of past pCO2 to be placed on Cenozoic timeslices. Further, our hypothesis has implications for the response of marine calcifiers to ocean acidification. Geologically "ancient" species, which have survived large changes in ocean chemistry, are likely more resilient to predicted acidification.

scholarly journals A coccolithophore concept for constraining the Cenozoic carbon cycle

2007 ◽  
Vol 4 (3) ◽  
pp. 323-329 ◽  
Author(s):  
J. Henderiks ◽  
R. E. M. Rickaby
Keyword(s):  
Carbon Dioxide ◽  
Temperature Sensitivity ◽  
Atmospheric Carbon Dioxide ◽  
Fossil Fuels ◽  
Ice Core ◽  
Atmospheric Composition ◽  
Physiological Plasticity ◽  
Polar Ice ◽  
Extant Species ◽  
Evolutionary Memory

Abstract. An urgent question for future climate, in light of increased burning of fossil fuels, is the temperature sensitivity of the climate system to atmospheric carbon dioxide (pCO>sub>2). To date, no direct proxy for past levels of pCO2 exists beyond the reach of the polar ice core records. We propose a new methodology for placing a constraint on pCO2 over the Cenozoic based on the physiological plasticity of extant coccolithophores. Specifically, our premise is that the contrasting calcification tolerance of various extant species of coccolithophore to raised pCO2 reflects an "evolutionary memory" of past atmospheric composition. The different times of evolution of certain morphospecies allows an upper constraint of past pCO2 to be placed on Cenozoic timeslices. Further, our hypothesis has implications for the response of marine calcifiers to ocean acidification. Geologically "ancient" species, which have survived large changes in ocean chemistry, are likely more resilient to predicted acidification.

10 Be and δ 2 H in polar ice cores as a probe of the solar variability’s influence on climate

1990 ◽  
Vol 330 (1615) ◽  
pp. 463-470 ◽  
Keyword(s):  
Mass Spectrometry ◽  
Stable Isotope ◽  
Ice Core ◽  
Ice Cores ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
South Pole ◽  
Polar Ice ◽  
Temperature Dependent ◽  
The Past

By using the technique of accelerator mass spectrometry, it is now possible to measure detailed profiles of cosmogenic (cosmic ray produced) 10 Be in polar ice cores. Recent work has demonstrated that these profiles contain information on solar activity, via its influence on the intensity of galactic cosmic rays arriving in the Earth’s atmosphere. It has been known for some time that, as a result of temperature-dependent fractionation effects, the stable isotope profiles δ 2 O and δ 2 H in polar ice cores contain palaeoclimate information. Thus by comparing the 10 Be and stable isotope profiles in the same ice core, one can test the influence of solar variability on climate, and this independent of possible uncertainties in the absolute chronology of the records. We present here the results of such a comparison for two Antarctic ice cores; one from the South Pole, covering the past ca . 1000 years, and one from Dome C, covering the past ca . 3000 years.

scholarly journals The Recovery and Dating of Carbon Dioxide in Polar Ice Cores

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 579-584 ◽  
Author(s):  
A T Wilson ◽  
D J Donahue
Keyword(s):  
Carbon Dioxide ◽  
Ice Core ◽  
Ice Cores ◽  
New Method ◽  
Polar Ice

A new method is described for recovering trapped CO2 from polar ice cores. The ice is sublimed under vacuum, and H2O vapor and CO2 are collected at appropriate cold traps. The application of this method to obtain CO2 from a specific ice core, the conversion of that CO2 to graphite, and the measurement of radiocarbon in the CO2 are described in detail. The potentialities and problems of the method are discussed.

scholarly journals Oxygen and silicon β-factors of zircon estimated from first principles

2019 ◽  
Vol 27 (4) ◽  
pp. 420-430
Author(s):  
D. P. Krylov
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Isotope Fractionation ◽  
Isotopic Equilibrium ◽  
Functional Theory ◽  
Empirical Calibration ◽  
The Density Functional Theory ◽  
Cubic Polynomials ◽  
Semi Empirical ◽  
Fractionation Factors

Zircon β-factors have been calibrated against temperature for isotopic substitutions of 18O/16O and 30Si/28Si. Calculations were performed using the density functional theory (DFT) with the “frozen phonon” approach. The deduced geometric parameters of the zircon unit cell, and the phonon frequencies calculated, agree well with the experimental data. The results are expressed by the cubic polynomials on x = 106/T(K)2: 1000lnβzrn(18O/16O) = 9.83055x – 0.19499x2 + 0.00388x3;  1000lnβzrn(30Si/28Si) = 7.89907x – 0.17978x2 + 0.00377x3. The expressions deduced can be utilized to construct geothermometers if combined with β-factors of coexisting phases. New calibrations of quartz-zircon are given. The new values of 1000lnβzrn and the estimated isotope fractionation factors between quartz and zircon (1000lnβqtz–1000lnβzrn) deviate considerably from previously used experimental, empirical, and semi-empirical calibration of the isotopic equilibrium.

scholarly journals Polar ice stratigraphy from laser-light scattering: scattering from meltwater

1994 ◽  
Vol 40 (136) ◽  
pp. 504-508 ◽  
Author(s):  
Michael Ram ◽  
Matthias Illing
Keyword(s):  
Light Scattering ◽  
Sample Size ◽  
Tree Ring ◽  
Laser Light ◽  
Ice Core ◽  
Ice Cores ◽  
Laser Light Scattering ◽  
Polar Ice ◽  
The Core ◽  
Considerable Success

Abstract We describe a new laser-light-scattering instrument for measuring variations in dust concentration along polar ice cores. We have used this instrument with considerable success on the GISP2 ice core from central Greenland. Reproducibility is excellent and the required ice-sample size is relatively small. When combined with visual stratigraphy and ECM, the distinct annual spring/ summer dust peaks we observe can be used to date the core with tree-ring-like precision.

scholarly journals Towards radiocarbon dating of ice cores

2009 ◽  
Vol 55 (194) ◽  
pp. 985-996 ◽  
Author(s):  
M. Sigl ◽  
T.M. Jenk ◽  
T. Kellerhals ◽  
S. Szidat ◽  
H.W. Gäggeler ◽  
...  
Keyword(s):  
Aerosol Particles ◽  
Ice Core ◽  
Ice Cores ◽  
Swiss Alps ◽  
Carbonaceous Aerosol ◽  
Polar Ice ◽  
Low Latitude ◽  
Bolivian Andes ◽  
Glacier Ice ◽  
Dating Method

AbstractA recently developed dating method for glacier ice, based on the analysis of radiocarbon in carbonaceous aerosol particles, is thoroughly investigated. We discuss the potential of this method to achieve a reliable dating using examples from a mid- and a low-latitude ice core. Two series of samples from Colle Gnifetti (4450 m a.s.l., Swiss Alps) and Nevado Illimani (6300 m a.s.l., Bolivian Andes) demonstrate that the 14C ages deduced from the water-insoluble organic carbon fraction represent the age of the ice. Sample sizes ranged between 7 and 100 μg carbon. For validation we compare our results with those from independent dating. This new method is thought to have major implications for dating non-polar ice cores in the future, as it provides complementary age information for time periods not accessible with common dating techniques.

Environmental records from polar ice cores

1990 ◽  
Vol 330 (1615) ◽  
pp. 459-462 ◽  
Keyword(s):  
Solar Activity ◽  
Ice Core ◽  
Ice Cores ◽  
Polar Ice ◽  
Cosmogenic Isotope ◽  
Wide Range ◽  
Recent Part ◽  
Ice Core Records

Polar ice cores provide a wide range of information on past atmospheric climate (temperature, precipitation) and environment (gas and aerosol concentrations). The dating can be very accurate for the more recent part of the records but accuracy decreases with depth and time. Measurements of cosmogenic isotope concentrations (such as 10 Be) provide information on palaeo-precipitation rates and particular events can be used to correlate ice core records. Besides these climatic applications, 10 Be concentration records in ice cores also contain information on solar activity changes.

scholarly journals AMS Radiocarbon Dating of Ice: Validity of the Technique and the Problem of Cosmogenic In-Situ Production in Polar Ice Cores

Radiocarbon ◽  
1992 ◽  
Vol 34 (3) ◽  
pp. 431-435 ◽  
Author(s):  
A. T. Wilson ◽  
D. J. Donahue
Keyword(s):  
Carbon Dioxide ◽  
Radiocarbon Dating ◽  
Ice Cores ◽  
Polar Ice ◽  
Ams Radiocarbon Dating ◽  
In Situ Production ◽  
Sublimation Technique

In the “sublimation technique,” carbon dioxide entrapped in ice is recovered by sublimation, converted to graphite and ratio of 14C/13C in the CO2 determined by AMS measurements. We describe here several experiments performed to check the validity of such measurements and to study the effect of cosmogenically produced in-situ14C on the measurements.

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