DEEV JAHI MODEL OF THE PERMIAN – TRIASSIC BOUNDARY (PTB) MASS EXTINCTION

The smoking gun revealing the secrets of the end Permian mass mortality is a unique 1 m-thick synsedimentary, abiotic, seafloor calcite cement that occurs precisely at the PTB in Iran, Armenia, Turkey, and China. Its temporal coincidence with the PTB suggests that the process that promoted seafloor cementation was also responsible for the biological crisis.

The d13C composition of the cement layer and the adjacent carbonates (0 to -2‰ PDB) is 4 to 7‰ PDB lower than the typical Upper Permian values (4 to 5‰ PDB), suggesting the release of 3.2 to 4.7 x 10¹⁸ g of CH4 from gas hydrates (d13C of -60‰ PDB) into the PTB ocean. Oxidation of CH4 in the water column formed a seawater that was charged with CO2 (an oceanic acid bath) dissolving a massive amount of platform carbonates leading to increases in Ca and HCO3 concentrations of seawater. When the release of CH4 declined, the warm acid-bath ocean became a soda ocean precipitating the seafloor cement layer observed globally at the PTB.

Therefore prior to cement precipitation, the injection of CH4 in to the PTB ocean generated a seawater that was charged with CO2, had lower than normal O2 (but not anoxic), high Ca, high HCO3, and warm, collectively creating an stressful condition causing the marine mass mortality. The leakage of CH4 to the atmosphere produced a super-hot climate resulting in the biological devastation on land. The proposed kill mechanism is based of the physical clue (the cement layer) left behind by the killing process (the change in ocean chemistry).

Periodic release of gas hydrate-derived CH4 explains many other mass extinction events of the Phanerozoic. It appears that CH4 has played the role of the Deev Jahi – a female demon in Persian mythology – whose only task is to attack the Earth every so often to kill life on land and in sea. The Deev Jahi may be tempted to visit the Earth once more should the current rates of release of CH4 to the modern ocean continue or accelerate.