The contemporary degassing rate of 40Ar from the solid Earth

被引:55
作者
Bender, Michael L. [1 ]
Barnett, Bruce [1 ]
Dreyfus, Gabrielle [1 ,2 ]
Jouzel, Jean [2 ]
Porcelli, Don [3 ]
机构
[1] Princeton Univ, Dept Geosci, Princeton, NJ 08544 USA
[2] Univ Versailles St Quentin, Inst Pierre Simon Laplace, Lab Sci Climat & Environm, CNRS,CEA,CE Saclay, F-91191 Gif Sur Yvette, France
[3] Univ Oxford, Dept Earth Sci, Oxford OX1 3PR, England
关键词
geochronology; ice cores; geodynamics; noble gases;
D O I
10.1073/pnas.0711679105
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
Knowledge of the outgassing history of radiogenic Ar-40, derived over geologic time from the radioactive decay of K-40, contributes to our understanding of the geodynamic history of the planet and the origin of volatiles on Earth's surface. The Ar-40 inventory of the atmosphere equals total Ar-40 outgassing during Earth history. Here, we report the current rate of Ar-40 outgassing, accessed by measuring the Ar isotope composition of trapped gases in samples of the Vostok and Dome C deep ice cores dating back to almost 800 ka. The modern outgassing rate (1.1 +/- 0.1 x 10(8) mol/yr) is in the range of values expected by summing outgassing from the continental crust and the upper mantle, as estimated from simple calculations and models. The measured outgassing rate is also of interest because it allows dating of air trapped in ancient ice core samples of unknown age, although uncertainties are large (+/- 180 kyr for a single sample or +/- 11% of the calculated age, whichever is greater).
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页码:8232 / 8237
页数:6
相关论文
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