Quick Links

Deep-sea volcanoes don’t just produce 
lava flows, they also explode!

Published: 28 Mar 2011

McGill geology researchers’ discovery of high concentrations of CO2 at mid-ocean ridges
confirms explosive nature of certain volcanic eruptions

McGill geology researchers’ discovery of high concentrations of CO2 at mid-ocean ridges
confirms explosive nature of certain volcanic eruptions

Between 75 and 80 per cent of all volcanic activity on Earth takes place at deep-sea, mid-ocean ridges. Most of these volcanoes produce effusive lava flows rather than explosive eruptions, both because the levels of magmatic gas (which fuel the explosions and are made up of a variety of components, including, most importantly CO2) tend to be low, and because the åvolcanoes are under a lot of pressure from the surrounding water.

Over about the last 10 years however, geologists have nevertheless speculated, based on the presence of volcanic ash in certain sites, that explosive eruptions can also occur in deep-sea volcanoes.

But no one has been able to prove it until now.

By using an ion microprobe, Christoph Helo, a PhD student in McGill’s Department of Earth and Planetary Sciences, has now discovered very high concentrations of CO2 in droplets of magma trapped within crystals recovered from volcanic ash deposits on Axial Volcano on the Juan de Fuca Ridge, off the coast of Oregon.

These entrapped droplets represent the state of the magma prior to eruption. As a result, Helo and fellow researchers from McGill, the Monterey Bay Aquarium Research Institute, and the Woods Hole Oceanographic Institution, have been able to prove that explosive eruptions can indeed occur in deep-sea volcanoes. Their work also shows that the release of CO2 from the deeper mantle to the Earth’s atmosphere, at least in certain parts of mid-ocean ridges, is much higher than had previously been imagined.

Given that mid-ocean ridges constitute the largest volcanic system on Earth, this discovery has important implications for the global carbon cycle which have yet to be explored.

For an abstract of the article: http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo1104.html

This research was funded by:

R.H.Tomlinson, GEOTOP, and J.W. McConnell Memorial Fellowships

David and Lucille Packard Foundation

Natural Sciences and Research Council of Canada (NSERC)

 

The complete article is available on request.

(Photo: Bands of glowing magma from submarine volcano)

SOURCE: NOAA/National Science Foundation

http://www.noaanews.noaa.gov/stories2009/20091217_volcano2.html

 

 

 

 

Contact Information

Contact: Katherine Gombay
Organization: Media Relations Office, McGill University
Email:
Office Phone: 514 398-2189
Source Site: /newsroom
Classified as: