Lake Suigetsu has the world’s longest varves
(45m long piled up for 70,000 years!)

Outline of varves

varves

Varves in Lake Suigetsu

What are varves?

Varves refer to the sediment with characteristic striped pattern piled up in the lake bed for an extremely long period of years. One new layer made up of light and dark coloured stripes is formed each year and this striped pattern is piled up alternately. The colour difference arises from different types of sediment depending on the season.

The process of varve formation

Suigetsu Varves ─ A Global Standard Scale for Dating.

Unavoidable inaccuracy in age determination

One of the means of identifying the age of excavated articles is radiocarbon dating. This is the method for determining the age by using the proportion of radiocarbon (carbon 14) present in the sample and comparing it against the standard air.

The shortcoming of this radiocarbon dating, however, is that inaccuracy occurs in age determination of excavated articles that ranges from several hundred to several thousand years. Radiocarbon contained in animals and plants was originally taken in from the one that exists in the atmosphere. However, the amount of radiocarbon (carbon 14) contained in the atmosphere varies from period to period. Therefore, the amount of radiocarbon of the same kind of animals and plants varies depending on the period.

In order to correct this inaccuracy, it is essential to have the results of radiocarbon dating of samples whose dates are known. It is varves that serve as this accurate measure.

More accurate age determination

We can identify the exact age of varves and leaves intercalated in the varve in Lake Suigestsu. Measuring the proportion of radiocarbon in the leaves, the relationship between the age and radiocarbon proportion become clear and consequently, the age of excavated artifacts can be accurately determined.

As “a global standard measure” in archaeology and geology, varves of Lake Suigetsu have dramatically improved the precision of age determination compared to conventional measuring methods.

Lake Suigetsu

The Miracle Lake "Lake Suigetsu Varves"

Lake Suigetsu, which is one of the Five Lakes of Mikata known as a scenic spot, is an ideal lake in terms of the environment for varve formation for the following three reasons. ① It has no river to flow in directly. ② Absence of life in the lake bed ③ It has not been filled up by sediment despite the lapse of time. These rare natural conditions are close to a miracle.

Due to the reasons mentioned in ① and ② above, the lake bed has not been stirred, which has contributed to the formation of beautiful striped pattern of varves. Moreover, fault activity around Lake Suigetsu does not allow the lake to be filled up by sediment and, therefore, as mentioned in ③, varves have been continuously formed in the lake bed for as long as 70,000 years. No other lake in the world has longer succession of varves accumulated for such a long period of years than Lake Suigetsu does.

What we can learn about past climate from the varves

forest Varves give us clues not only of identifying the specific age of excavated articles, but of finding out what the ancient natural environment was like such as general climate, the appearance of forests in ancient time, etc. Examining the species and amount of pollen from the plants around the lake that are confined in the varves makes it possible to simulate what the appearance of the forest and general view around the lake were like in ancient time.

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Location

122-12-1 Torihama, Wakasa-cho, Mikatakaminaka-gun, Fukui Prefecture 919-1331, JAPAN
inside Jomon Roman Park (adjacent to Wakasa Mikata Jomon Museum)

TEL

+81-770-45-0456

FAX

+81-770-45-3680

MAIL

varve-museum@pref.fukui.lg.jp

Opening hours

9:00 to 17:00(Entrance gate closes at 16:30.)

Closed days

every Tuesday & Year-end and New Year holidays (12/29 to 1/2)

If a national holiday falls on a Tuesday, the following day becomes a closed day.
No closed days during the Golden Week holidays and the summer holidays
We are subject to temporary closure due to maintenance of our facility, etc.

Admission fee

Adults: 500 yen / Students (aged 6 to 18): 200 yen

Combo ticket covering Wakasa Mikata Jomon Museum is 30 percent off.
A group over 20 people is 20 percent off.

Permanent exhibition	Individual	Ordinary admission ticket	Adults	500 yen
		Ordinary admission ticket	Students (aged 6 to 18)	200 yen
		Combo ticket covering Wakasa Mikata Jomon Museum	Adults	700 yen
		Combo ticket covering Wakasa Mikata Jomon Museum	Students (aged 6 to 18)	280 yen
	Group	Ordinary admission ticket	Adults	400 yen per person
		Ordinary admission ticket	Students (aged 6 to 18)	160 yen per person
		Combo ticket covering Wakasa Mikata Jomon Museum	Adults	560 yen per person
		Combo ticket covering Wakasa Mikata Jomon Museum	Students (aged 6 to 18)	220 yen per person

Admission is free for visitors over 70 and under 6.　People over 70　are required to show their ID cards verifying their age such as health insurance card, etc.
Group discount is applied to a group of over 20 people except those eligible for free entrance.
Admission is free for the students in Fukui Prefecture aged 6 to 18, including students in special support education schools and people in charge of each student group. (Prior reservation is required.)
No admission fee is required for the visitors who produce their physical disability certificate or certificate for livelihood assistance or education assistance at the information desk.
No admission fee is required for all the visitors on Family Day (every 3rd Sunday) and Hometown Day (February 7).

Our facility

70-space parking area (shared with Wakasa Mikata Jomon Museum)
3 wheelchair & 2 stroller
Multipurpose toilet & bed for diaper change
Elevator
In case of using a wheelchair, please tell us at the information desk. Our staff will assist the visitor in wheelchair.

Requests to the visitors

Please refrain from eating and drinking in the museum.
Smoking is prohibited in the museum.
Entry with your pets into the museum is prohibited except with helper dogs.
Please refrain from any nuisance to other visitors such as making a noise in a loud voice, running around in the exhibition rooms or down the hall, etc.

Explanation of exhibits

Up to three guides are permanently stationed in the museum, who explain our exhibits to the visitors. Should you have any questions, please feel free to ask them.
As for our guidance service, priority is basically given to the visitors with advanced reservation. When we have many visitors, however, please note that there are cases where we can’t provide appropriate guidance service.

Reservation

Prior reservation is recommended as much as possible for the group visitors. Without reservation, you may not be guided smoothly.
Please feel free to contact us by phone, fax and email for your reservation.
In case of visiting us in a group of over fifty people, we recommend that the entire group be divided into more than two smaller groups and visit us and Jomon Museum adjacent to our museum alternately. Over fifty visitors at a time may make our guides unable to provide appropriate guidance service. In that case, please consult with us in advance.