Liquid carbon dioxide of magmatic origin and its role in volcanic eruptions

A.R. Chivas; I. Barnes; William C. Evans; J.E. Lupton; J.O. Stone

doi:10.1038/326587a0

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Liquid carbon dioxide of magmatic origin and its role in volcanic eruptions

A.R. Chivas·I. Barnes·William C. Evans·J.E. Lupton·J.O. Stone

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Abstract

Natural liquid carbon dioxide is produced commercially from a 2.5-km-deep well near the 4,500-yr-old maar volcano, Mount Gambier, South Australia. The carbon dioxide has accumulated in a dome that is located on the extension of a linear chain of volcanic activity. A magmatic origin for the fluid is suggested by the geological setting, δ 13 C PDB of –4.0‰, for the CO 2 (where PDB represents the carbon-isotope standard), and a relatively high 3 He component of the contained helium and high 3 He/C ratio (6.4 x 10 −10 ). The 3 He/ 4 He and He/Ne ratios are 3.0 and > 1,370 times those of air, respectively. The CO 2 , as collected at the Earth's surface at 29.5 °C and 75 bar, expands more than 300-fold to form a gas at 1 atm and 22 °C. We suggest that liquid CO 2 or high-density CO 2 fluid (the critical point is 31.1 °C, 73.9 bar) of volcanic origin that expands explosively from shallow levels in the Earth's crust may be a major contributor to 'phreatic' volcanic eruptions and maar formation. Less violent release of magmatic CO 2 into crater lakes may cause gas bursts with equally disastrous consequences such as occurred at Lake Nyos, Cameroon, in August 1986.

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Source-reported bounding extent: -43.6346° to -10.66819° latitude; 113.33895° to 153.56947° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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A.R. Chivas, I. Barnes, William C. Evans, J.E. Lupton, J.O. Stone. 1987. Liquid carbon dioxide of magmatic origin and its role in volcanic eruptions. https://doi.org/10.1038/326587a0

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