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

Nature
By: , and 

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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, δ13CPDB of –4.0‰, for the CO2 (where PDB represents the carbon-isotope standard), and a relatively high 3He component of the contained helium and high 3He/C ratio (6.4 x 10−10). The 3He/4He and He/Ne ratios are 3.0 and > 1,370 times those of air, respectively. The CO2, 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 CO2 or high-density CO2 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 CO2 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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Publication type Article
Publication Subtype Journal Article
Title Liquid carbon dioxide of magmatic origin and its role in volcanic eruptions
Series title Nature
DOI 10.1038/326587a0
Volume 326
Issue 6113
Year Published 1987
Language English
Publisher Nature Publishing Group
Description 3 p.
First page 587
Last page 589
Country Australia
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