Methane is the principal component of natural gas, and massive amounts of it are trapped in reservoirs beneath the sea floor and under a layer of the ice-like substance.
The archaeologists put the shoe's remarkable preservation down to the stable, cool and dry conditions in the cave and the fact that the floor of the cave was covered by a thick layer of sheep dung.
As a broker-dealer, MF Global also added liquidity to the system, adding another layer of systemic risk: on Monday, MF Global traders were barred from the CME Trading floor, substantially limiting liquidity in futures markets.