Nav: Home

Methane seeps in the Canadian high Arctic

April 13, 2017

Boulder, Colo., USA: Cretaceous climate warming led to a significant methane release from the seafloor, indicating potential for similar destabilization of gas hydrates under modern global warming. A field campaign on the remote Ellef Ringnes Island, Canadian High Arctic, discovered an astounding number of methane seep mounds in Cretaceous age sediments.

Seep mounds are carbonate deposits, often hosting unique fauna, which form at sites of methane leakage into the seafloor. Over 130 were found covering over 10,000 square kilometers of the Cretaceous sea floor. They occurred over a very short time interval immediately following onset of Cretaceous global warming, suggesting that the warming destabilized gas hydrates and released a large burb of methane. Given that methane has 20 times the impact of CO2 as a greenhouse gas, such a release could have accelerated global warming at that time. This discovery supports concerns of potential destabilization of modern methane hydrates.

Background

A field campaign was run during 2009-2011 to map the geology of Ellef Ringnes Island. Around the same size as Jamaica, this is one of the most remote and difficult to access islands in the Canadian High Arctic, and as such not much was known about the geology. A remote helicopter supported field camp was established in 2009, with a peak of 30 geoscientists working from the camp in 2010 as part of the Geological Survey of Canada's GEM Program. The island, and its neighbor Amund Ringnes Island, were named after brothers who founded Norway's Ringnes Brewery that funded the exploration of the region conducted by Otto Sverdrup in the early 1900s

As part of this work, Krista Williscroft, Stephen Grasby, and colleagues intended to reinvestigate strange spaghetti-like rock that was noticed, but the origin not understood, during the first geologic mapping of the island in the 1970s. Years later, a geologist saw a sample of this feature sitting on his colleague's desk and was intrigued by its spaghetti like nature. Chemical analyses revealed that this was a carbonate rock formed by the oxidation of methane, and the spaghetti texture was formed by fossil tube worms. This was shortly after the first discovery of methane cold seeps in the modern oceans and became the first recognition of such features in the geologic record. In this case, it was known to have formed during the Cretaceous, the time of the dinosaurs roamed the earth, around 110 million years ago. Sadly, these original samples were lost, and given the remoteness of the location, it was not possible to gain more, limiting any further work.

Methane Cold Seeps

Methane cold seeps are similar to the more famous black smokers in that they form isolated ecosystems as oasis in the deep ocean, but are lower temperatures and form away from mid-ocean ridges. They forms at sites were natural methane gas leaks into seawater. Microbes oxidase this methane as a source of energy and produce carbonate deposits as a by-product. In the modern world, these sites are characterized by an unusual abundance of tube worms, bivalves (clams), molluscs, and other animals that survive on the microbial mats that grow there. In the rock record, they stand out as very unusual features that have this strange spaghetti-like appearance related to fossil tube worms and an abundance of other fossils. As they form in deep water they also stand out as resistant carbonate mounds in rock that is otherwise easily eroded shale.

New Discovery

In 2010 the intention was to revisit the site first discovered in the 1970s. It stood out as a small mound on the otherwise rolling landscape of arctic tundra. From this site another mound could be seen in the distance, which raised the tantalizing possibility of a second site. Some hard walking through thick mud paid off when it was reached, revealing another fossil methane seep. From there a further mound could be seen, and on and on. This lead to more than four weeks of trudging from mound to mound through muddy tundra, and the discovery of over 130 methane seep mounds in the rock record. This is now one of the most extensive sites of these features known anywhere in the world, covering more than 10,000 square kilometers.

Implications

A key feature of this discovery is recognition that all the seep mounds formed during a very narrow range of geologic time. Because they form by leakage of methane into seawater it implies that something at that time caused a large release of methane into the ocean. The timing is coincident with a period of global warming, and Williscroft and colleagues suggest that it was this warming that released methane frozen as methane hydrates in the sea floor, as a relatively sudden methane "burp." If correct, this has important implications for modern warming of the Arctic Ocean. Similar frozen methane hydrates occur throughout the same arctic region as they did in the past, and warming of the ocean and release of this methane is of key concern as methane is 20x the impact of CO2 as a greenhouse gas. Release of methane hydrates has previously been suggested as a mechanism to drive runaway greenhouse events, as warming oceans releases trapped methane that causes further warming and releases more methane. The extensive methane seep mounds across the remote arctic island of Ellef Ringnes may be a caution from the past regarding potential impacts of modern warming of the Arctic Ocean.
-end-
FEATURED ARTICLE

Extensive Cretaceous methane seepage, Ellef Ringnes Island, Canadian High Arctic Krista Williscroft, Stephen E. Grasby, Benoit Beauchamp, Crispin T.S. Little, Keith Dewing, Daniel Birgel, Terry Poulton, and Krzysztof Hryniewicz; http://gsabulletin.gsapubs.org/content/early/2017/04/07/B31601.1.abstract.

Contact: Steve Grasby, steve.grasby@canada.ca. Images are available from Steven Grasby.

GSA BULLETIN articles published ahead of print are online at http://gsabulletin.gsapubs.org/content/early/recent. Representatives of the media may obtain complimentary copies of articles by contacting Kea Giles. Sign up for pre-issue publication e-alerts at http://www.gsapubs.org/cgi/alerts for first access to new content. Please discuss articles of interest with the authors before publishing stories on their work, and please make reference to The Geological Society of America Bulletin in articles published. Non-media requests for articles may be directed to GSA Sales and Service, gsaservice@geosociety.org.

http://www.geosociety.org

Geological Society of America

Related Global Warming Articles:

A new study provides a solid evidence for global warming
The new study allows a more accurate assessment of how much heat has accumulated in the ocean (and Earth) system.
Global warming hiatus disproved -- again
UC Berkeley scientists calculated average ocean temperatures from 1999 to 2015, separately using ocean buoys and satellite data, and confirmed the uninterrupted warming trend reported by NOAA in 2015, based on that organization's recalibration of sea surface temperature recordings from ships and buoys.
Report reassesses variations in global warming
Experts at the European Centre for Medium-Range Weather Forecasts (ECMWF) have issued a new assessment of temperature trends and variations from the latest available data and analyses.
Clouds are impeding global warming... for now
Lawrence Livermore National Laboratory researchers have identified a mechanism that causes low clouds -- and their influence on Earth's energy balance -- to respond differently to global warming depending on their spatial pattern.
Global warming's next surprise: Saltier beaches
Batches of sand from a beach on the Delaware Bay are yielding insights into the powerful impact of temperature rise and evaporation along the shore that are in turn challenging long-held assumptions about what causes beach salinity to fluctuate in coastal zones that support a rich network of sea creatures and plants.
Could global warming's top culprit help crops?
A new study tries to disentangle the complex question of whether rising amounts of carbon dioxide in the air might in some cases help crops.
Evaporation for review -- and with it global warming
The process of evaporation, one of the most widespread on our planet, takes place differently than we once thought -- this has been shown by new computer simulations carried out at the Institute of Physical Chemistry of the Polish Academy of Sciences in Warsaw.
Researchers reveal when global warming first appeared
Human caused climate change is increasingly apparent today through multiple lines of evidence.
1,800 years of global ocean cooling halted by global warming
Prior to the advent of human-caused global warming in the 19th century, the surface layer of Earth's oceans had undergone 1,800 years of a steady cooling trend, according to a new study in the Aug.
Global sea levels have risen 6 meters or more with just slight global warming
A new review analyzing three decades of research on the historic effects of melting polar ice sheets found that global sea levels have risen at least six meters, or about 20 feet, above present levels on multiple occasions over the past three million years.

Related Global Warming Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#530 Why Aren't We Dead Yet?
We only notice our immune systems when they aren't working properly, or when they're under attack. How does our immune system understand what bits of us are us, and what bits are invading germs and viruses? How different are human immune systems from the immune systems of other creatures? And is the immune system so often the target of sketchy medical advice? Those questions and more, this week in our conversation with author Idan Ben-Barak about his book "Why Aren't We Dead Yet?: The Survivor’s Guide to the Immune System".