INTRAPERMAFROST GAS HYDRATES FROM A DEEP CORE-HOLE IN THE MACKENZIE DELTA, NORTHWEST-TERRITORIES, CANADA

Visible gas hydrate and possible pore-space hydrate samples have been recovered for the first time in North America from within ice-bonded p ermafrost in a 451-m-deep core hole in the Mackenzie Delta, Northwest Territories, Canada. The visible hydrate was found as thin icelike Lay ers that released methane gas initially upon retrieval, but stabilized for up to 4 h at atmospheric pressure conditions and subfreezing temp eratures, The temporary stabilization of hydrate samples is attributed to the self-preservation phenomenon described by others on the basis of laboratory studies. High methane concentrations in well-ice-bonded sediments and gas releases suggest that pore-space hydrate may be foun d at depths as shallow as 119 m. Geochemical and isotopic determinatio ns suggest that the methane hydrate observed in the core hole is bioge nic (microbial) in origin.