Paleoclimate Saw-tooth pattern & natural gas clathrate hydrates

Chung-Chieng Lai

Henry’s Law:concentration in water =

K × pressure in air

Saw-tooth pattern; Temperature leads CH4 that leads CO2

570

CH4 + 2 O2 CO2 + 2 H2O + Heat

catalyst

Bacteria, etc.

Heat: 195,000 cal / mole of CH4

810,000 J

400

750

400200

(a)

(b)

(c)

(d)

Methane hydrate

Structure I binary hydrate:

46H2O + 6(mG) + 2(sG)

sG – small-size gas, such as N2

mG – medium-size gas, such as CH4

Clathrasil (mineral) at work

46 SiO2·6(lG)·2(sG)

sG: N2, Ar, Xe, CH4

lG: N2O, CO2, Kr, Xe,

CH3NH2 (methylamine)

Dissociation:

Gas hydrate → gas + water

Gas hydrate solid to gas phase boundary:

T = T0 + a log (P/P0) (1)

T, T0, a : temperature

P, P0 : pressure

Phase boundary plots