Natural Deposits Methane
hydrates are restricted to the shallow lithosphere (i.e.
< 2000 m depth). Necessary conditions are found only either
in polar continental sedimentary rocks where surface
temperatures are less than 0 °C; or in oceanic sediment at
water depths greater than 300 m where the bottom water
temperature is around 2 °C.
In addition, deep lakes may host gas hydrates as well.
Continental deposits have been located in Siberia and Alaska
in sandstone and siltstone beds at less than 800 m depth.
Oceanic deposits seem to be widespread in the continental
shelf and can occur within the sediments at depth or close
to the sediment-water interface. They may cap even larger
deposits of gaseous methane.
