metagenesis
1. n. [Shale Gas]
The last stage of maturation and conversion of organic matter to hydrocarbons. Metagenesis occurs at temperatures of 150° to 200°C [302° to 392°F]. At the end of metagenesis, methane, or dry gas, is evolved along with nonhydrocarbon gases such as CO2, N2, and H2S, as oil molecules are cracked into smaller gas molecules.
Catagenesis and diagenesis and metagenesis.