Recently, the research results of the global standard stratotype profile and point position (commonly known as "golden nail") at the bottom of the Permian Guadalupian Capitanian completed by the scientific research team headed by Shen Shuzhong, academician of the Chinese Academy of Sciences, were published online in the official journal episodes of the International Federation of geological Sciences. The Kapitan period is the most critical period in the geological history, during which the pan continent changed from north-south convergence to east-west division, the earth's magnetic field changed from super static period to frequent inversion period (iravara inversion event), the global sea level fell to the lowest point of Phanerozoic, and the pre lepinian (end of Guadalupe) biological extinction event all occurred. Therefore, the publication of "golden nail" is of great significance for the study of the above Phanerozoic super events. The "golden nail" called by the International Geological community is the only global standard for dividing geological ages and strata. This "golden nail" was put forward as early as the 1990s. Together with the Rhodian and ward stages of Guadalupe (Middle Permian), it was voted as the international standard for the division of Guadalupe by the Permian branch of the international stratigraphic Commission. "Although the international stratigraphic Commission and the International Union of Geosciences officially approved the 'golden nail' in 2001, the actual materials of its profile and whether it can be used for international correlation and other related research have not been officially published in any publications, and the conodonts used to define the standard point are not shown." Shen Shuzhong pointed out that the "golden nail" has not played a global comparative role as an international boundary standard for a long time. Through cooperation with a number of scientific research institutions at home and abroad, the international working group led by Shen Shuzhong led the late Paleozoic team of Nanjing University and Nanjing Institute of Geology and paleontology, Chinese Academy of Sciences to go to Guadalupe mountain area in the United States for four times in more than ten years to measure and prepare profiles in detail, collect samples and fossils, and conduct comprehensive research on detailed biology, chemical stratigraphy and volcanic ash high-precision geochronology. The "golden nail" of the kapitanian stage is located in the nipple Hill section in the Guadalupe mountain area of the United States. The section only exposes 0.5m above the bottom boundary of the kapitanian stage, which is difficult to conduct detailed long-scale biostratigraphic research. In order to solve this problem, the research team found a new section containing this boundary about 2.9 kilometers west of the section and conducted in-depth research on the auxiliary stratotype section. Systematic high-precision zircon chronology shows that the age of the bottom boundary of the kapitanian stage is 264.28 ± 0.16ma (one million years); The results of magnetic stratigraphic correlation show that the iravara inversion is located slightly below the bottom boundary of the kapitanian stage; The study of strontium isotope chemical stratigraphy shows that the strontium isotope ratio (87Sr / 86Sr) continues to decline throughout the kapitanian stage; Inorganic carbon isotope results show that there is no obvious carbon isotope drift at the junction of ward stage and kapidonian stage. (Xinhua News Agency)
Edit：Huang Huiqun Responsible editor：Huang Tianxin
Source：gmw.cn
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