In the field of geology, the significance of "golden nails" is no less than Olympic gold medals. The "golden nails" hidden deep in the geological layers are the only global standard for dividing geological age. In June 2025, the 69th global and the 11th Chinese "golden nail" permanent emblem of the global Wuliu terrace will be nailed in Jianhe, Guizhou. What is special about this "golden nail" that has settled in the deep mountains of southwestern China? How does it interpret the Earth's code from 506 million years ago for global geologists? Recently, Yang Xinglian, a member of the board of directors of the Chinese Society of Paleontology and a member of the research team for China's 11th global "golden nail" of the Ulou Formation, was interviewed on this matter. The summary of the interview transcript is as follows: Reporter: What is the "golden nail"? Why does the international geological community need a 'golden nail' to define stratigraphic age? Yang Xinglian: The "golden nail" is not a nail made of gold, but a geological term commonly used by the International Commission on Stratigraphy to define the geological boundaries of geological units, such as the "global boundary layer profile and point location", borrowed from the "history of railway construction". It not only refers to special nodes in geological records and their important scientific value, but also vividly expresses that it is a geographical "point" with special meaning "nailed" into the surface of the earth, and is a "caliper" for measuring the age of strata. The Earth has a 4.6 billion year history of evolution, and the mysteries of life evolution are preserved in layers of rocks. Due to the lack of a unified standard or "common language", there have been significant differences in the classification of age strata among countries around the world in the past, resulting in difficulties in global stratigraphic classification and correlation. In order to clarify the evolution of the Earth, scientists have established chronostratigraphic units divided by time boundaries, with "from largest to smallest" being "universe, boundary, system, series, and stage". The chronostratigraphic table is divided into about 110 stages, and the boundary between every two geological epochs is marked by a "golden nail". At present, more than 100 "golden nails" have been established worldwide, with 82 of them established in China, ranking among the top in terms of quantity. Reporter: In June 2025, the 69th global and 11th Chinese "golden nail" permanent emblem of the global Wuliu terrace was nailed in Jianhe, Guizhou. Why did this "golden nail" settle in Jianhe? Yang Xinglian: The "golden nail" nailed to Jianhe, Guizhou was approved by the International Union of Geological Sciences in June 2018. The research on the "golden nail" was led by Professor Zhao Yuanlong of Guizhou University, and completed by an international team composed of experts from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Ohio State University and other units. The international academic community has extremely strict standards for identifying the "golden nail", which involves multiple evaluation dimensions such as geology, paleontological conditions, transportation convenience, accessibility, and conservation status according to the requirements of the International Commission on Stratigraphy. The permanent symbol of the "Golden Nail" of the global Wuliu Formation can be nailed into the Wuliu Zengjiaya section in Balang Village, Gedong Town, Jianhe County, Guizhou Province, mainly due to three important factors: firstly, the superior geological and biological conditions and good accessibility of the Jianhe area; Secondly, Professor Zhao Yuanlong from Guizhou University has been leading a team to conduct long-term and in-depth comprehensive research on the area since 1983; Thirdly, the People's Government of Guizhou Province has approved the area as a provincial-level nature reserve since 2002, and in 2009 it became the core area of Miaoling National Geopark, receiving permanent protection. Compared to other globally competitive profiles, the Jianhe Wuliu Zengjiaya profile is more continuous and rich in fossils, with more complete stratigraphic outcrops above and below the boundary point. It has convenient local transportation and is located in a national geological park, which is conducive to protection. Moreover, the research is the most in-depth, conducting comprehensive studies in multiple disciplines such as rock, biology, age, chemistry, and sequence stratigraphy, fully meeting the international requirements for the "golden nail" profile. What is particularly special is that the Jianhe "Golden Nail" not only contains a rich group of trilobite animals mainly composed of cephalopods, but also preserves a large number of soft bodied fossils of the Kaili biota immediately above the "Golden Nail" site, including 10 fossil categories and more than 120 animal fossil genera, which has important scientific significance. Reporter: How did this "golden nail" located in Jianhe, Guizhou accurately time the geological age of 506 million years ago worldwide? What key information did it reveal about the Earth's environment and the evolution of life at that time? Yang Xinglian: In the process of Earth's evolution, there are the most typical organisms in each era, and finding iconic fossils is the key basis for determining different stratigraphic eras. The International Commission on Stratigraphy requires that the location of the "golden nail" be marked by the "first appearance" representing the fossil. Through research, the team proposes to define the Cambrian 3rd and 5th bottom boundaries based on the first appearance of the Indian trilobite trilobite in the Wuliu Zengjiaya section of Jianhe River. Its first appearance point is coupled with major geological events such as the extinction layers of the Ledeckii trilobite and the small oil comb trilobite, as well as global carbon isotope negative anomalies. At present, the latest version of the International Chronostratigraphic Table shows that the age of the Cambrian Miaoling Formation (3rd Series) and Wuliu Formation (5th Stage) bottom is determined by integrating global biostratigraphic data of these trilobites, combined with high-precision U-Pb dating data of tuff and detrital zircon, to "accurately date" the geological age of 506 million years ago worldwide. More than 500 million years ago was a crucial period in the history of biological evolution and ecological innovation. At that time, the oxygen content in the ocean and atmosphere rapidly increased, leading to a major evolutionary event known as the "Cambrian Explosion" of rapid radiation from post protozoa. The Kaili biota that appeared above the "Golden Nail" point in Jianhe provides irreplaceable evidence for revealing the origin of animal species and early ecosystem evolution. Reporter: Currently, there are 11 "golden nails" established in China, ranking among the top in terms of quantity. What role does this achievement play in enhancing China's discourse power in the field of earth sciences? How can humans better protect the 'golden nail'? Yang Xinglian: The establishment of the "golden nail" reflects the comprehensive strength of a country's geological research. According to the requirements of the International Commission on Stratigraphy, a permanent symbol should be established for the "golden nail" after approval, and the country where it is located should properly protect the "golden nail". If it is not easy to nail down a "golden nail", protecting these rare geological relics is also a difficult problem of the times. Currently, the main challenges are the natural weathering and erosion of the "golden nail" profile, geological disasters, and even human damage, as well as the common challenge of how local governments balance protection and development conflicts. Therefore, it is urgent to implement dynamic maintenance of the "golden nail" profile, strengthen scientific popularization to enhance public awareness of protection, and introduce laws and regulations for the protection of the "golden nail". The protection of the "golden nail" should go beyond the academic scope and become a shared responsibility of the government, society, and the public. At the same time, we will explore the integration and development of science popularization research and local cultural tourism industry, and build "Golden Nail" into a geological and cultural brand that integrates scientific research, science popularization education, and ecological tourism, realizing the development path from "Golden Nail" to "Golden Idea" and then to "Golden Key", and assisting in the revitalization and construction of rural areas. (Xinhua News Agency) Interviewee Profile: Yang Xinglian is a professor at the School of Resources and Environmental Engineering, Guizhou University, a council member of the Chinese Society of Paleontology, and a visiting scholar at Ohio State University in the United States. Her research focuses on early metazoa and Cambrian strata. In 1999, she joined the 11th Chinese and Guizhou's first global Wulian "golden nail" research team.