Influence mechanism of transgressive events on source rock development in continental lacustrine basin

Transgression is one of the important events affecting the development of source rocks in lacustrine basin, and the status quo of this issue was reviewed upon summarizing relevant literature in China and the world. Transgressive events are widely distributed in the Songliao Basin, Bohai Bay Basin, Subei Basin in China, and many other in other countries. Transgression can be identified by paleorelic markers, mineral petrological markers, and geochemical imprints. Generally, transgressive source rocks are characteristic of high abundance and good type of organic matter, which is mainly due to the obvious promotion by transgressive events to the development of source rocks. On the one hand, transgression may bring abundant nutrients to lake water and significantly improve the productivity of ancient lakes. On the other hand, salinity may be conducive to the formation of stable water stratification and a strong reducing environment at the water bottom, which could promote the preservation of organic matter. Taking the Termit Basin in the West African rift type as an example, the model of marine transgression affecting the development of lacustrine source rocks is summarized.