Environment for the formation of petroleum source rocks

Abstract

Pollen and spores in crude oils and source rocks provide other types of useful geological information. The evolution, flourishing, and demise of plants and plant communities are closely related to climatic changes. The original plants that shed the spores and pollen found in crude oils from petroliferous basins of China mainly belong to mosses, ferns, cycads, conifers, and angiospermous dicotyledons. Most of the plants are classified as humidogene thermophytes. Geographical factors are also important for vegetational development. The geographical distribution of the plant and algal remains in crude oils can help interpret paleogeographical landscapes consisting of mountains, rivers, lakes, marshes, deltas, littoral lagoons, and oceans. Thirdly, the ecological characteristics of the original plants indicate that the petroleum source rocks in the inland petroliferous basins were probably formed in lacustrine and swamp/marsh sedimentary environments under warm and humid climatic conditions.