The Geology of Mud Volcanism

6. Dolomitization, Silicification, Argillization and Late Carbonates – Calcite in UDH context (Sucrosic and saddle dolomite, silica and quarts, clays and black shales)

The crystallization of other oxygen-rich minerals, such as dolomite, quartz, clay, and calcite, also contribute to the process of hydrogenation of kerogen by grabbing the oxygen from water, leaving the hydrogen free to attach to the kerogen. Sucrosic (sugary) dolomites are among the first to crystallize, followed by silica (quartz), clay (illite) in black shales, saddle dolomites, and finally calcite.