“Chibanian” Stratum to Be Natural Monument in Japan

June 18, 2018

Tokyo- The Cultural Affairs Council recommended on Friday that a stratum in Chiba Prefecture, eastern Japan, be designated as a natural monument, citing its significance as a representing observation point for the beginning of a geological period that could be called "Chibanian."

The stratum along the Yoro River in the city of Ichihara shows traces of a reversal in the Earth's magnetic field. Analysis of volcanic ash indicates that it was formed 770,000 years ago.

The advisory body for the culture minister pointed out that the layer, not far from Tokyo, is easy to observe and extremely valuable academically.

The designation will be made as proposed shortly.

Last year, a Japanese research team applied to the International Union of Geological Sciences for recognition of the stratum as a point representing a shift in geological time.

If the request is approved, a geological period between 126,000 and 770,000 years ago will be named Chibanian after the location, becoming the first such period to bear a Japanese name.

Initially, the group, including researchers from Ibaraki University and the National Institute of Polar Research, expected the IUGS screening to end smoothly. However, it has now been suspended due to a question about data sampling raised by a separate group in Japan.

The Ibaraki University-led team welcomed the de facto natural monument designation, saying it will help clear one of conditions for the Chibanian naming. Jiji Press