Editing Methane clathrate (section)

===Continental===
Methane clathrates in continental rocks are trapped in beds of [[sandstone]] or [[siltstone]] at depths of less than 800 m. Sampling indicates they are formed from a mix of thermally and microbially derived gas from which the heavier hydrocarbons were later selectively removed. These occur in [[Alaska]], [[Siberia]], and [[Northern Canada]].

In 2008, Canadian and Japanese researchers extracted a constant stream of natural gas from a test project at the [[Mallik gas hydrate site]] in the [[Mackenzie River]] delta. This was the second such drilling at Mallik: the first took place in 2002 and used heat to release methane. In the 2008  experiment, researchers were able to extract gas by lowering the pressure, without heating, requiring significantly less energy.<ref>{{Cite news |first=Brodie |last=Thomas |title=Researchers extract methane gas from under permafrost |url=http://www.nnsl.com/northern-news-services/stories/papers/mar31_08ma.html |work=Northern News Services |date=2008-03-31 |access-date=2008-06-16 |url-status=dead |archive-url=https://web.archive.org/web/20080608011136/http://nnsl.com/northern-news-services/stories/papers/mar31_08ma.html |archive-date=2008-06-08}}</ref> The Mallik gas hydrate field was first discovered by [[Imperial Oil]] in 1971–1972.<ref>{{cite web |url=http://gsc.nrcan.gc.ca/gashydrates/mallik2002/index_e.php |title=Geological Survey of Canada, Mallik 2002 |access-date=2013-03-21 |work=Natural Resources Canada |date=2007-12-20 |url-status=dead |archive-url=https://web.archive.org/web/20110629141558/http://gsc.nrcan.gc.ca/gashydrates/mallik2002/index_e.php |archive-date=June 29, 2011}}</ref>