Diagenesis, Catagenesis and Metagenesis of Organic Matter

Abstract

The physicochemical transformation of organic matter during the geological history of sedimentary basins cannot be regarded as an isolated process. It is controlled by the same major factors that also determine the variations of composition of the inorganic solid phase and of the interstitial water of the sediments: biological activity in an early stage, then temperature and pressure. Furthermore, organic-inorganic interaction can occur at different stages of the sediments evolution. Nature and abundance of organic matter may result in different behavior of the mineral phase, shortly after deposition; composition of minerals and structure of the rock may influence composition and distribution of organic fluid phases at depth. An excellent picture of the conditions of deposition and early history of sediments has been given by Strakhov (1962), and will be frequently used in the following paragraphs.