It is Korea that the "Chiba section" of the stratum in Ichihara City, Chiba Prefecture is the international standard model layer cross section and the point that marks the beginning of the mid-Pleistocene of the geological era (about 77 years ago to about 4,000 years ago). It was recognized at a meeting of the International Union of Geological Sciences held in Busan, Chiba.As a result, the official name of the Middle Pleistocene was named "Chibanian".
According to the National Institute of Polar Research, this is the first time that the Japanese strata have been selected as the Global Boundary Stratograph and Point.The examination of the Global Boundary Stratograph and the site, which marks the beginning of the Middle Pleistocene, has been underway since 2017, and the International Union of Geological Sciences has been examining the Chiba section along with the two sites in Italy.
The history of the earth is divided into 117 geological eras, with milestones due to cooling and impacts of meteorites.For example, the beginning of the Pleistocene is named Gelasian, the next is Calabrian, etc., but about 10 including the Middle Pleistocene have not been officially named so far.
The research team, represented by Professor Makoto Okada of the Faculty of Science, Ibaraki University, found traces of geomagnetic reversal in the Chiba section and applied for examination as a stratum representing an era.The Chibanian name will be used worldwide in textbooks and research papers.Professor Okada said, "I am deeply moved by the fact that the geological formations of Japan will be engraved in the history of the earth. I am grateful to the local people and everyone who supported the Chibanian."
