| Summary: | Beaufort Mackenzie (BMB) permafrost and methane gas hydrate (GH) occurrences appear paradoxical. Relict terrestrial permafrost and GH from the Pleistocene sea level lowstand are degrading slowly in response to marine transgression below the Beaufort Sea. In many onshore Mackenzie Delta (MD) locations, such as at the Mallik site, thick permafrost and GHs are also degrading slowly in response to Holocene ground surface temperature warming. In contrast, taliks commonly lacking GH indications are inferred below shallow lakes.Why should taliks form below shallow lakes while submarine permafrost and GHs persist? We compare models of talik, permafrost and GH behavior below such lakes and compare them to models of BMB GH occurrence to describe lacustrine inundation effects and the factors controlling the contrasting MD permafrost/GH and talik environments.
|
|---|