Deposition, diagenesis and weathering of organic matter-rich sediments / Отложение, диагенез и выветривание богатых органическим веществом отложений

The major objective of this text is to provide information on characteristics of organic matter in sedimentary rocks and to relate these characteristics to processes relevant in their deposition, diagenesis, and weathering. 
Organic matter derived from biological precursors is a constituent of most sedimentary rocks. Its amount in recent and subrecent sediments is known to be controlled by a variety of physical and chemical factors such as transport distance from the site of plant growth to the site of deposition or oxygen content of water at the sedimentJwater interface. It is generally assumed that the same factors also influenced the concentration of organic matter in ancient sediments, i.e., the deposition of petroleum source rocks. This actualistic principle can, however, not be used for the explanation of all source rocks. For example, shelf areas were probably much greater than at present during and after times of intense transgression such as at the end of the lower Toarcian or at the Cenomanian/Turonian boundary. Another example is the occurrence of widespread coals derived from tropical peats in the Upper Carboniferous which is an effect of a much greater continental lowland area in the tropical belt than at present. In view of their economic significance, the evaluation and quantification of the most important parameters that govern the deposition of sediments rich in organic matter is a major goal in organic sedimentology (Huc, 1988). Studies on recent and subrecent sediments should mainly emphasize the relationship between environmental controls and the characteristics of the sediments. <...>