Diffuse gas emissions at the Ukinrek Maars, Alaska: Implications for magmatic degassing and volcanic monitoring

Applied Geochemistry
By: , and 

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Abstract

Diffuse CO2 efflux near the Ukinrek Maars, two small volcanic craters that formed in 1977 in a remote part of the Alaska Peninsula, was investigated using accumulation chamber measurements. High CO2 efflux, in many places exceeding 1000 g m−2 d−1, was found in conspicuous zones of plant damage or kill that cover 30,000–50,000 m2 in area. Total diffuse CO2 emission was estimated at 21–44 t d−1. Gas vents 3-km away at The Gas Rocks produce 0.5 t d−1 of CO2 that probably derives from the Ukinrek Maars basalt based on similar δ13C values (∼−6‰), 3He/4He ratios (5.9–7.2 RA), and CO2/3He ratios (1–2 × 109) in the two areas. A lower 3He/4He ratio (2.7 RA) and much higher CO2/3He ratio (9 × 1010) in gas from the nearest arc-front volcanic center (Mount Peulik/Ugashik) provide a useful comparison. The large diffuse CO2 emission at Ukinrek has important implications for magmatic degassing, subsurface gas transport, and local toxicity hazards. Gas–water–rock interactions play a major role in the location, magnitude and chemistry of the emissions.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Diffuse gas emissions at the Ukinrek Maars, Alaska: Implications for magmatic degassing and volcanic monitoring
Series title Applied Geochemistry
DOI 10.1016/j.apgeochem.2008.12.007
Volume 24
Issue 4
Year Published 2009
Language English
Contributing office(s) Volcano Hazards Program
Description 9 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Applied Geochemistry
First page 527
Last page 535
Country United States
State Alaska