Japan's first GSSP "Chibanian (Chiba era)"

"Chibanian" Tabuchi's geomagnetic reversal stratum is certified as GSSP (Global Boundary Stratographic Layer Cross Section and Points)!

 The outcrop "Chiba section" of Tabuchi along the Yoro River is a stratum deposited in the deep sea, which later appeared when the Boso Peninsula was uplifted.
 Here, traces of the newest geomagnetic reversal phenomenon that occurred about 77 years ago could be continuously analyzed and observed.By analyzing microfossils and pollen contained in the strata as well as the reversal of the geomagnetic field, research is being conducted on the environment of the sea and land at that time.
 Such strata are only in the southern part of the Boso Peninsula and the southern part of Italy. Among them, the Tabuchi stratum has the best conditions for observation, so it was selected as the GSSP (Global Boundary Stratographic Strata and Points) of the geological age boundary. It was done. As a result of being certified by the GSSP, the era starting from the boundary of this stratum (about 77 to 4 years ago, mid-Pleistocene Quaternary) is called "Chibanian" (Latin for "Chiba era"). It was decided to call it.
 This is a feat that the Japanese place name was given to the geological age name for the first time.

Guidance facility

Ichihara Tabuchi Geomagnetic Reversal Geomagnetic Reversal Visitor Center
(Nickname) Chibanian Visitor Center


290 Tabuchi, Ichihara City, Chiba Prefecture 0546-1157

Phone number / FAX


Business hours

9:00 - 16:00

Regular holidays

Every Thursday, New Year holidays (December 12-January 29)
* If Thursday is a national holiday, the closed day will be changed to the day before the closed day.


[For those who go by car]
・ Please set 290 Tabuchi, Ichihara 0546-1165 (Tabuchi Kaikan) as your destination.
・ Go south on Prefectural Road 81 (Kiyosumi / Yoro Line), turn right at the "Chibanian" sign, and follow the road to the Chibanian Visitor Center and temporary parking lot (45 cars).
* After turning right at the signboard, the road from the entrance of Tabuchi Hall to the temporary parking lot is a living road for the town council, and the width of the road is narrow, so please be careful, such as slowing down according to the instructions on the information board on the way.
* Large buses cannot enter the temporary parking lot from the prefectural road.Please check with the visitor center in advance for parking locations.

[For those who go by Kominato Railway]
・ From Goi Station on the JR Uchibo Line, change to the Kominato Railway Line, get off at Tsukizaki Station, and walk for about 30 minutes (2 km).
* You can rent a bicycle at the Asahiya Y shop opposite Tsukizaki station. (The number is limited)

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