Finding the secrets of forest remains! 310 million-year-old fossil wood group in Yangquan, Shanxi Province is "out of the circle"

Science and Technology Daily (Reporter Han Rong) On November 29, the reporter learned that the Nanjing Institute of Geology and Paleontology of the Chinese Academy of Sciences discovered a mineralized plant community dating back 310 million years ago in Yangquan City, Shanxi Province, which is also the remains of the oldest forest in North China . The relevant research papers were published in the international academic journals "Reviews in Paleobotany and Palynology" and "Ancient World".

In October 2022, the Yangquan City Geological Disaster Prevention and Control Center discovered some wood fossils with good mineralization and clear wood structure in the first set of limestone interlayers above the suburban bauxite layer. This is the lowest and oldest wood fossil preserved in the rock strata in Yangquan City. Experts from the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences, have conducted research on this.

Since the 1930s, domestic and foreign experts have conducted a series of studies on the Late Carboniferous flora in North my country. Limited by the poor preservation of fossils and the lack of in-depth research, the systematic taxonomic research on the Late Carboniferous plants in my country stagnated at the beginning of this century.

Researchers conducted anatomical research on more than 60 mineralized woods collected in Yangquan, and discovered for the first time the tree-type Cordaean plants of the Late Carboniferous period in my country, including Damudimu, Li's Kauri-type wood, and Uda's Kauri-type wood, as well as the early conifer (broadly defined) plant Paraiba wangii.

Wang Keyu, a member of the Carboniferous-Permian plant research team of the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences, introduced that according to the empirical formula of plant allometric growth, it was calculated that the Corda plants in the Cathaysian flora during the Late Carboniferous could grow to a height of 30 meters, correcting the erroneous view of European and American paleobotanists that there was no high-rise vegetation during the deposition period of the Benxi Formation in my country during the Late Carboniferous.

Forest ecosystems are the main body of terrestrial ecosystems and have important ecological service functions. Wang Keyu said that this study also discovered the oldest "nursery wood" phenomenon to date. The "nursery wood" phenomenon refers to the stems or stumps of plants that provide nutrients and water for the germination of seeds and the growth of seedlings of other plants after death and decay, which can ensure the stability and sustainable development of forest communities . However, due to the lack of fossil evidence, the academic community does not know much about the origin and evolution of "nursery trees". In the wood fossils discovered this time, the researchers found that the stems of Cordae plants were interspersed with a large number of "small roots" of gymnosperms, indicating that the "nursery wood" phenomenon had appeared in the Chinese flora 310 million years ago.

It is worth mentioning that the researchers also found a considerable number of beautifully preserved fungal fossils and a large number of fecal fossils in the wood fossils. Based on the analysis of the size, shape, surface structure and other characteristics of the fecal fossils, the researchers speculated that these feces were left behind by oribatid mites when they were feeding on wood.

"Combining the previous research results with the latest findings of this study, in the early stages of the evolution of the Cathaysian flora, plant diversity, especially the diversity of gymnosperms, was much higher than we had previously known. The study of mineralized plants can to a large extent make up for the deficiency of the preservation of impression fossils being affected by the sedimentary environment." Wang Keyu said that this study shows that ecological phenomena such as plant-arthropod, plant-fungus, and plant-plant interactions were already very common in the Cathaysian plant geographical region during the Late Carboniferous, indicating that the terrestrial ecosystem structure at that time was already very complex.