solid clathrate compound (more specifically, a clathrate hydrate) in which a large amount of methane is trapped within a crystal structure of water, forming a solid similar to ice.
They mostly are on the bottom of the world's oceans; however, the overly brief wikipedia section for continental deposits suggests that it also occurs in Siberia, northern Canada and Alaska.
How much methane clathrates are believed to be buried in these continental deposits?
