New Discovery and Significance of Microbialites of the Middle Ordovician Majiagou Formation in Liujiang Basin, Hebei, China

The concept, classification, genesis, and significance of microbialites have been constantly improving for over a century, but they are still hot spots in the field of geology because of the strong attractions and many unsolved mysteries such as the mechanism of the microbial deposition process, the microbial induced sedimentary structures, and so on. At the same time doubt and confusion arises among students and beginners because of the mysteries. Generally, any findings of various stromatolites, oncolites, and thrombolites are all classified under microbialites. Moreover, microbialites have also been discovered from the middle Ordovician Majiagou formation in Liujiang Basin, Hebei, China. As an important geological practice base for thousands of students and beginners every year, in order to enhance the interest in geosciences the further research of the microbialites found in Liujiang Basin is necessary. In this study, the classification scheme of microbialites has been summarized. On this basis, the study shows that the main microbialites in the study area are microbial carbonate rocks, which include wavy, columnar, conical-shaped stromatolite carbonate rocks and oncolite carbonate rocks. The variety, macroscopic characteristics, and clear internal features of microbialite carbonate rocks are all have considerable significance in judging hydrodynamic conditions, sedimentary environment, paleogeographic characteristics, and biological evolution. And the evolutionary process of different kinds of microbialites has been discussed. However, the roles of microbialites in the formation mechanism and ecological significance are still need further study. With the new discovery of microbialites from the middle Ordovician Majiagou formation in Liujiang Basin, a new window of study microbialites has been opened for everyone. More findings and detailed characteristics of microbialites in this area are urgently needed during geological practice.